# Question
Title: Which of the LEGO Mindstorms 9797 (NXT Education base set) Software is compatible with Windows 10
I have LEGO Mindstorms NXT 9797 and downloaded the following Windows PC Versions:

* NXT Edu 2.1F6 PC App ---Education Version
* NXT Ret 2.0F5 PC App ---Home Version

Which one of these are compatible with Windows 10 home version 64bit?

Is EV3 software a better choice for this one?

Your guidance is highly appreciated.

# Answer
You're in luck; All versions of the NXT software, including drivers, is compatible with 64-bit Windows 10. While in my experience it wasn't necessary, you can preemptively avoid installation problems by right-clicking "Setup.exe" and clicking Properties -\> Compatibility -\> Run in compatibility mode for: -\> Windows XP SP3 . In the same panel you should select "Run as Administrator" to avoid permission problems.

While the EV3 software is backward-compatible with the NXT, the NXT software is a much better option. Certain NXT options are not available using the EV3 software (like bluetooth support). And in my experience, the NXT software is just more stable anyway.
> 2 votes

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Tags: mindstorms, nxt, software
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# Question
Title: What is this light grey LEGO plate with six sides (hexagon)?
I've been unable to find this specific piece's name, just for the reason that it is a very unorthodox piece.

# Answer
> 57 votes
Informally, it's known as the Nexogon.

Bricklink calls it "Plate, Modified 6 x 6 Hexagonal with Pin Hole". The part number is 27255. It's original use was as a shield in the Nexo Knights line in 2017, but it has appeared in a few other sets since then.

If you're interested in ways to use this part, New Elementary did a whole series of posts from different builders when it was first released. The unique shape and different connection families open up a lot of fun opportunities.

# Answer
> 9 votes
This is what I managed to create with the Nexogons:

Flickr Album: https://www.flickr.com/photos/162108633@N02/albums/72157688876724660

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Tags: part-identification
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# Question
Title: I have a LEGO minifigure and I'm trying to determine the value of it
I have a minifigure and I am trying to determine it's value - I'd like to know whether it's worth holding on to it for longer, or if I would get a reasonable price for it now.

# Answer
At the moment (12/09/2018) there are a few other people offering that figure for sale on BrickLink, varying from £110 to £230 (actual asking prices are in various currencies listed on the results page).

More importantly however, is the Price Guide page \- from there you can see that one figure apparently was bought this month for about £72, however in July one was purchased for around £108, while another was purchased for about £83.

From that, you could probably get a sale at around £100, but it might take a while to sell.
> 5 votes

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Tags: shopping, minifigures
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# Question
Title: Why can't I reproduce this SD card box in LDD?
I've built an SD card box a few years ago. Now I am trying to reproduce it in Lego Digital Designer.

However when I tried to reproduce the closed version, LDD refuses to snap it in place.

In real-life, my box just snap very nicely. Why am I not allowed to do that in LDD?

Here is the WIP `.lxf` file

# Answer
> 29 votes
The issue here is that the hole in a Technic brick isn't at exactly the same height as the stud on the side of a System brick. Here's a slide from a great presentation which explains the details:

This difference is barely noticable when building, especially in your scenario because the hinge adds some additional play, but I believe that LDD won't allow these to connect because they are actually off by .12mm.

I tried to take a few pictures to demonstrate what I mean, but they didn't turn out very well. Here's a System brick (tan) connected to a Technic brick (blue). You can just barely see the .12mm difference at the top:

The difference becomes more obvious when more bricks are added so that the error is allowed to compound:

# Answer
> 5 votes
LDD uses exact numbers, where as in real life ABS and polycarbonate have some give or flexibility that a computer program can't factor in. There are many documents about LEGO part stress that explain what a "legal" vs "illegal" build is. Any illegal build will not work in LDD. I break the rules all the time too, but LDD is looking at it from a pure math sense, which you can't cheat. Try and create a curved wall made of stressed 1x2 in LDD. You can do it in real life, but not in the program.

# Answer
> 4 votes
Try de-attaching the black piece and then attach it to the 2x2 and plate and attach all the pieces at the same time

# Answer
> 2 votes
Interesting... I just tried this myself (with real bricks) and the two parts definitely snap together nicely. No stress or anything. I'm wondering if the issue is the 1x2 plate. Maybe LDD can't deal with a hinged part having to snap into two places at once. What about if you remove the bottom 1x2 yellow plate? Would it snap in then? In that case perhaps first attach the 1x2 to the healight bricks, then attach the hinge-plate to the hinge, then rotate it towards the plate and see if it would snap on the 1x2 plate.

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Tags: ldd
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# Question
Title: Could you help me identify these vintage bricks with holes in the studs?
I recently got a bulk lot of official Lego pieces from a charity shop. Amongst my treasures I discovered a load of these bricks (about 40 or so).

At first I thought they were some of the first Lego bricks but as far as I can tell Lego have always had the tubes on the underside of their bricks. Can anyone help me to identify their pedigree and/or their age? I have a very strong feeling they're knock-offs...

Distinguishing features -

* These bricks have nothing on the underside to stop them from sliding around- no tubes, ridges, nothing.
* The larger bricks (2x4 upwards) have holes all the way through the studs.
* All bricks have a slightly sunken profile to the studs
* Every brick has a random number on the underside i.e. “43”, “78” etc
* In basic colours of red, blue, yellow, white, black and clear. I’ve also got a green baseplate which has square holes on the underside.

Thanks for any help you can give me.

# Answer
LEGO made plastic bricks from 1949 and didn't get the patent for the tubes underneath until 1958, in the years between they made plenty of bricks with nothing underneath.

Many (I don't remember if it's all) of the (larger) LEGO bricks from that era, has a slot in one side.

That being said, with the small holes through the studs on the 2x4 and the slightly recessed studs, these bricks doesn't look like anything I've ever seen from LEGO.

Square holes underneath I have seen though, so that's not an argument against your green plate being LEGO, but without having seen it, I can't say for sure.
> 3 votes

# Answer
This looks like an early competitor. Blue-Box and Rasti kinda look alike, but it's definitely not those. I'm fairly sure it's not Lego (I own several early Lego bricks, prototypes and bricks made under licence).

This site has a lot of info on Early Lego bricks and competitors of that time: https://www.inverso.pt/legos/
> 3 votes

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Tags: part-identification, vintage
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# Question
Title: Is possible to change firmware of ev3 brick?
I bought LEGO 31313 but I would like to change the firmware for education (45544).

1.09H to 1.09E. Is this possible?

# Answer
Connect EV3 with USB to computer, have Lego Mindstorm software open

Under Tools -\> Select Firmware update and start he update

Brick will restart after firmware is updated
> 6 votes

# Answer
Yes, this is totally possible and I have done it multiple times. You will need access to both firmware files though - AFAIK there is no menu to choose versions.
> 3 votes

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Tags: ev3
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title: Stuck on 42066 Air Race Jet model B

text:
# Question
Title: Stuck on 42066 Air Race Jet model B
I've successfully built model A of the Air Race Jet but with model B I've got stuck on page 7, instruction 8. How do you do that?

# Answer
Nice job finishing Model "A"!

As for Model "B", known as "Private Jet", follow *this link* and head on over to *Youtuber THINK LOUDER's* speed build of this model.

* First, Mute the video.
* Second, Pause the video.
* Third, Open the setting for video playback, which is the "Gear" icon in the bottom right hand corner of the video, to slow down the speed to "0.25".
* Forth, Play the video and skip to minute 1:47 into the video.
* Fifth, and finally, Watch how this guy builds up until minute 2:04 into the video, which is where you are stuck, page 7, instruction 8.

Good luck! You can do it Bro!
> 8 votes

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Tags: technic, building
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# Question
Title: Is there any way to find misplaced bricks in LEGO NXT Programming?
I am working on a Mindstorms NXT project. Due to annoying bug (cannot find terminal hotpoint thingy) I can't delete a specific block, and if I do so, part of the program will be cut off from the main sequence. I deleted that block and the bug happened, and not knowing what happened, I saved it. I reopened it to find out that part of the program was cut from the main sequence and I tried searching the whole empty space but wasn't able to find it.

Is there any way of retrieving the lost blocks (other than searching) since the file size is still the same, meaning the lost blocks are just lying around somewhere.

# Answer
> 2 votes
I have had this problem in the past, and have not been able to find a solution, other than program it with the software meant for programming EV3s, as it is backward compatible (except that Bluetooth doesn't work, so that may be a problem as your photo shows Bluetooth blocks). Hope this helps!

# Answer
> 1 votes
Unfortunately, it's difficult/impossible to fix your program once the bug has occurred. You'll have to recreate the program from scratch (i.e. delete the file and start over).

There are a few ways to avoid this going forward:

* Save often. If the bug happens, DON'T overwrite your file! Revert to the previous save.
* Don't resize the white LEGO liftarm thing manually unless you have to. Always let the software decide the spacing between your blocks.
* Make sure you're using the latest version of the software (NXT-G 2.0). Download it here.

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Tags: mindstorms, nxt, programming
---


# Question
Title: Why do I not have the Brick Datalog app in the LEGO Mindstorms EV3 V1.10E firmware?
> I realize a similar question has been asked (you can view it here) however mine is slightly different.

I have a Lego Mindstorms EV3 Home Set 31313 and due to recommendation, I installed Lego Mindstorms Education EV3 Student Edition. I later changed my firmware on my EV3 to V1.09E. The next time I updated my firmware, however, I was unsure that the software was not installing the latest version so I ended up installing V1.10E using EV3 Manager. So it was to my surprise that the Brick Datalog app had disappeared!

Is there any way for me to get my app back without, of course, performing a downgrade and removing the ability for me to use Microsoft PXT? TIA!

# Answer
> 6 votes
Interesting insight. I didn't notice that it was missing. (I wonder if there was not enough room in the flash memory for both this and the new MakeCode stuff - or maybe it was just an accident).

I managed to find a hack to get the `Brick Datalog` program loaded again.

1. Download this zip file.
2. Unzip the file.
3. Open `Brick Datalog.ev3` in the EV3 programming software.
4. Download the project to your EV3.
5. Open the *Memory Browser*.
6. Browse to the `Brick Datalog` project, then click *Download*.
7. Select the `Brick Datalog.rbf` file (from where you unziped the file in step 2) and click *Open*.
8. Close the *Memory Browser*.
9. On the EV3 brick, you can now browse to the `Brick Datalog` project and run the `Brick Datalog` program (it won't be with the rest of the "apps" as in previous versions of the firmware).

How it works:

The brick apps use the same format as user-created programs on the EV3, so I just took the `Brick Datalog` app from the ev3dev lms2012-compat project (which is identical to the official LEGO version, but easier to get to). Then I created a new empty project in the EV3 Education software and imported all of the images and sounds. The software doesn't let you import `.rbf` files (the actual program), which is why it has to be downloaded separately via the *Memory Browser*.

I haven't tested this extensively, but it does seem to work.

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Tags: ev3
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title: Help to identify a small tube part

text:
# Question
Title: Help to identify a small tube part
I'd like some help identifying the black parts circled in the photo.

# Answer
> 7 votes
It's a piece of 3mm rigid hose. It looks something like this:

That particular piece must have been cut from a larger piece, as the smallest it has ever come is 3L (3 studs) and never black at that size.

It's debated if cutting tube pieces is a purist thing to do or not.

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Tags: part-identification
---


# Question
Title: How can I find overlapping bricks in LeoCAD?
I've just started using LeoCAD to generate instructions for a model I want to share. I've been able to get it working despite the sparse tutorials. But in looking at my results so far I see that I've got an extra part in one step. I'm pretty sure this is a left over from duping the same part over and over again. One benefit of this is that the part must be overlapping with another part. How can I find and remove this extraneous part?

# Answer
> 4 votes
I'm not aware of a way to do this in LeoCAD directly, but assuming that your overlapping brick is an exact duplicate (same element, same position, same rotation, etc) it will show up as a duplicate line in the LDraw file. Something as simple as this should show you what it is:

```
uniq -d model.ldr

```

You could also use any other tool for finding duplicate lines.

If you find a duplicate, it will look something like this:

```
1 4 -70 -48 -40 1 0 0 0 1 0 0 0 1 3005.DAT

```

The 3rd, 4th, and 5th items are the x,y, and z coordinates, which you can use to track down duplicate elements and remove them inside LeoCAD. Alternatively, you can remove all but one of the duplicate lines from the file directly.

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Tags: software
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# Question
Title: Please help identify a set with bag of tan, white, grey, and light-blue 1x1 and 1x2 bricks?
Help me identify what set this small bag goes to?

# Answer
> 2 votes
Recently, I bought a used 10214 London Tower Bridge. It came with all parts in one single bag. However, looking at the brick types and colors on the picture I would guess it is from 10214.

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Tags: set-identification
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# Question
Title: Please help identify what set this bag belongs to, white windows and fences, and tan circles
Bag indicates that it was made in 2011.

# Answer
This one is definitely from 10214 London Tower Bridge. I only have a used set that didn't have the original bags, but all parts and colors match perfectly.
> 3 votes

# Answer
The Technic Wedge Belt Wheel (Pulley) only comes in tan in 5 sets and the only one of those sets that has more than 2 (which your bag clearly does) is 10214 Tower Bridge.
> 2 votes

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Tags: set-identification
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# Question
Title: Stacking motors on the Powered Up hub or Boost hub
The way the Boost/Powered Up connectors are designed, it's not possible to have multiple motors on the same output of a hub like it was possible with 9V or Power functions. However, since I only want to stack the straightforward M-motors, the electronics should be simple enough for a DIY solution. Does anyone have a tutorial or pointers?

# Answer
> 3 votes
All you should have to do is connect pins 1 and 2 between the two motors. One motor will have all six wires connected and serve as the primary in order to give the hub something that it can properly identify. The second motor can simply piggyback off of the primary and share control voltages that are meant for the primary motor. Essentially, you can leave one set of identification circuitry in place, and then wire just the motors in parallel.

I'm not sure if Powered Up compatible connectors are available anywhere, but it's not too hard to open up the motors and connect to them that way. Here's what it looked like testing this out:

I paired pins 1 and 2 here and things worked as expected.

# Answer
> 1 votes
There really isn't any easy way to do this at the moment. I would suggest buying plugs and making a simple port splitter, but I don't think there's currently any place to purchase the parts.

The best you can do involves (permanently) splicing the wires of the two motors together, using a single plug for both of them. With only the M motors this shouldn't cause electrical problems but having two motors permanently attached to a single plug is obviously less than ideal.

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Tags: electronics, powered-up, boost
---


# Question
Title: What is inside the LEGO Powered Up M motor?
What is inside the M motor in the new Powered Up system? How is it different from the older Power Functions motor?

# Answer
> 12 votes
Let's take a look. The first step to disassembling the motor is removing the small Philips screw on the bottom:

Now there are a pair of gray tabs in the back white section that we need to release. I found it easiest to cut them down with a knife. Once those are free, the white section slides backwards away from the motor. Try to do this gently, as there are several gears inside that may go flying and be difficult to find.

The motor will be left in the back section.

It isn't fixed in place, so you can simply slide it free of the housing.

We can see that the PCB contains only a few very simple components. I believe that the larger element in the middle is a resettable fuse, and the smaller one on the left is a capacitor across the motor pins to minimize electrical noise. The tiny black element on the right is a 2.2kOhm resistor between pins 5 and 6 that allows the hub to identify this as an M motor.

We also have the gray section of the motor:

Down in the end, there is a planetary gearbox that slides out:

The gearbox simply slides open:

It contains two sets of planetary gears:

Overall, this is very similar to the PF M motor with the addition of a small PCB and a resistor to facilitate the component detection used by Powered Up. It's worth noting that this is the same motor used in WeDo 2.0.

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Tags: piece-information, motor, electronics, powered-up, disassembly
---


# Question
Title: How do I install the Lego BOOST software on a phone instead of a tablet?
Officially, the Lego Boost software is only available for devices with at least an 8 inch screen:

https://www.lego.com/en-us/service/device-guide/boost

However, it would be nice to install the software on an old phone rather than a tablet for my child to use. Is this possible? How?

Edit: LEGO now officially supports tablets and smartphones. This question is now mostly irrelevant, but it could still be useful as a guide to installing the app on an unsupported device.

# Answer
> 9 votes
You can install the software using an alternative App Store such as APKPure. You can alternatively download and install the APK and OBB files directly from various online sources as demonstrated in this video. Once installed, this software seems to work for me on my Galaxy S4, and I assume it would also work on other Android devices. I can connect to and control the Move Hub without any issues, but I haven't tested all features of the software.

I was unable to get this to work on an S3. The app crashes during the loading screen. This could be due to many factors, but I suspect screen resolution could be one culprit, as the S3 has a 720p screen and the S4 has a 1080p screen.

It should also be noted that these devices aren't officially supported by TLG, so this software may be buggy and/or stop working in the future.

Devices confirmed working:

* ASUS ZenPad S
* Google Pixel C
* HTC Nexus 9
* Lenovo Yoga Tablet 2
* Lenovo Yoga Tab 3
* Nvidia SHIELD Tablet (LTE)
* Samsung Galaxy Tab S
* Samsung Galaxy Tab A
* Samsung Galaxy Tab S2 (Nook)
* Sony Xperia Z2 Tablet (LTE)
* Sony Xperia Z3 Tablet Compact (LTE)
* Xiaomi Mi Pad 2
* Samsung Galaxy S4
* LG G3
* Samsung Galaxy S5
* Google Pixel 2
* BQ Aquaris X5 Plus
* Huawei P10 Lite
* Motorola G5 Plus

Devices confirmed not working:

* Galaxy S3

# Answer
> 0 votes
The official list of devices can be found here

https://www.lego.com/en-us/service/device-guide/boost

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Tags: boost
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# Question
Title: Which resistor value is used for which motor in Power Functions 2.0?
Based on the answer here it seems that resistors are used to detect what is plugged in with LEGO Power Functions 2.0. So which resistor values (or ranges) apply to which motors or other devices? Are there any values of resistance that lead to "unknown device" errors or something like that?

# Answer
> 7 votes
## M Motor (Powered Up/WeDo 2.0)

The M motor has a 2.2kΩ resistor between pins 5 and 6. Pin 6 is connected directly to pin 3.

## LED Lights

I don't own any lights yet, but according to this post, they also use a 2.2kΩ resistor, but in this case it is between pins 5 and 3. This pulls ID 1 to ground. Here's the full circuit diagram:

## Train motor

The measured resistance between pins 5 and 6 shows an open circuit. Pin 5 is connected directly to VCC, and pin 6 is connected directly to ground.

## Other components

I wasn't able to determine any sort of passive identification on any other components (Boost motor and sensors, etc). My guess is that these have an onboard microcontroller and use an active handshake before establishing a data connection.

## Summary

```
M Motor
3 (GND) ─────┐
4 (VCC)      │
5 (ID1) ─2.2k┤
6 (ID2) ─────┘

LED Lights
3 (GND) ─────┐
4 (VCC)      │
5 (ID1) ─2.2k┘
6 (ID2)

Train Motor
3 (GND) ───┐
4 (VCC) ─┐ │
5 (ID1) ─┘ │
6 (ID2) ───┘

```

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Tags: power-functions, motor, powered-up, boost, wedo
---


# Question
Title: What is an effective way to clean clear LEGO bricks?
What kind of cleaning products are good and safe to remove smudges and finger prints off clear LEGO parts? Normally I would just use the Clorox wipes. The parts in question are 1x2x2 panels in clear plastic.

# Answer
Almost all LEGO can be washed with dish soap and warm water (Do not use dish washer soap though, it sometimes contains grit to help grind off dried food. This will scratch your bricks)

Second best option is windex, which isn't too bad for plastics.

I would advise against clorox wipes though. I believe they contain bleach, which while is great for getting things clean, it will react with the ABS plastic.

I tried bleaching some old lego a number of years back, and I soaked the bricks for a day or two and I found that, while they wer very clean, they also slightly expanded as a result of reacting with the bleach. They are very sticky, and are hard to separate now. Additionally, they seem a little harder and less flexible.

Note that this occurred after being immersed in a water bleach mixture for extended time. One swipe of bleach will probably not have much effect, but it shows that it does react with the plastic, so that is why I suggest against it.

Warm water and dish soap cures most problems.
> 1 votes

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Tags: cleaning
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# Question
Title: What is the best way to sell sealed LEGO sets?
My kids have inherited a massive LEGO collection. 90%+ is in mint condition, still sealed. There are thousands of sealed boxes - currently kept in storage. There are plenty of open sets that the boys will keep, but the bulk we are looking to sell. What is the best way to do this? Any advice would be appreciated. A large amount of sets are Star Wars.

# Answer
If you really have that much (hundreds or more sets to move), you have some options:

Set up a Ebay store: Up front cost: None Profit: ~80% of net (Ebay takes a cut, Taxes, shipping materials) The slow burn option. You will eventually get rid of everything, but it will take some time, and many trips to the post office.

Go rent a table at a local Lego convention: Up front cost: probably a few hundred bucks Profit: After the booth /table cost, all the money is pretty much yours. This will get rid of stuff fast if you go to a sizable convention and you price reasonably. People buy a lot of lego at Lego conventions. You will have to plan this in advance, since tables might require being reserved months in advance.

Find a reliable Lego collector to sell it for you: I had a good friend who is an active member of the local Lego community do this for a family who acquired a huge vintage Lego collection. I think he took about a 20% cut and had most of it sold off in a few months. The upside of this approach is that you don't have to do anything but count the money you make. Make sure you get someone who knows what they are doing though. Older collectors are good choices, since they know a lot of the history of sets and themes.

I don't know how good sites liek Bricklink are for selling sets. It is a fantastic place to buy sell loose parts, but I don't know how quickly sets move there.
> 2 votes

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Tags: shopping, star-wars
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# Question
Title: Help me identify what set this bag of mostly white tiles and panels belongs to
Can anyone tell me what set this bag belongs to? It could be 2011 but not sure.

# Answer
As Aziraphale hinted at in a comment, this is a bag from Tower Bridge (10214).

You can see this bag clearly in unboxing videos.
> 3 votes

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Tags: set-identification
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# Question
Title: Can you identify a set containing a zebra and spider minifig?
I have 2 bags of unopened Lego bricks but I cannot determine what set they belong to...bag 2 344R6 and bag 4 344R6. They are probably from Lego Junior. I can tell there is a zebra character minifig and a spider character minifig.

# Answer
Batman baddie ZEEEeeeebra-Man,

and tough gurl TA-TAH-Taaaarantula !!!

From Set *70907-1 Killer Croc Tail-Gator*.
> 7 votes

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Tags: set-identification
---


# Question
Title: Can you identify this LEGO Space build from the early 90s?
Can anybody help me identify this LEGO model from this old picture. My son built this around late 80's / early 90's. The closest I can find is the 6956 Stella Recon Voyager set. Same colours and similar pieces. Has he perhaps joined up two sets and made this himself as I cannot find it anywhere. I am looking for parts inventory and instructions. I have a huge box of LEGO pieces I now want to pass on to my grandson. Sorry that the picture is not clearer.

Update:

Thank you for your feedback. Yes, I have managed to download the parts inventory and instructions for 6956. You are correct with 6886. I now definitely remember buying that for our son and those parts are in the box but I'm not too sure about 1968 it doesn't look familiar. I will have to ask my son who now lives abroad. It appears that, at the time the picture was taken, my son might have used his very active 10yr old imagination! Thank you for that info. I am also going to upload the only other picture I have taken from a different angle if this helps further. So, if I could just find out from what model those large black flat 'fins' and other side pieces might be from I think we might have solved the puzzle.

# Answer
Based on Slope 33 3 x 6 with MTron Logo Print - Red which only comes in 1 set: 6956-1: Stellar Recon Voyager this is the set you already mentioned.

I see a part that looks like: Flexible Hose 8.5L with Tabless Ends (Ends same color as Tube) in trans yellow. which come in several sets. I think it's 1968-1 - Space Expressssic Space 1968-1 as this set also contain some white wedge pieces, which look like used at both sides.

Based on Windscreen 10 x 4 x 2 1/3 Canopy - Trans-Red and Hinge Vehicle Roof Holder 1 x 4 - Blue 6886-1 - Galactic Peace Keeper is also is the collection

The rest parts is a lot harder to identify.
> 12 votes

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Tags: set-identification
---


# Question
Title: Can anyone explain the transformation information within a Lego Digital Designer LXF file?
I've been taking a look at the structure of the LDD files recently to see if it's feasible to create a plugin for 3D studio max that allows you to directly open LXF files for higher quality rendering...

It seems possible, but to get some preliminary tests happening I just need to understand exactly how the transformation string works:

transformation="0,0,1,0,1,0,-1,0,0,0.40000009536743164,0,-0.40000009536743164"

It seems pretty obvious from playing around that the last 3 relate to the position of the piece, and the first 9 somehow relate it's rotation (and perhaps 1 or 2 other things I'm not aware of yet). If anyone knows I'd love a detailed explanation as it would save me a LOT of messing around =)

Also are there any good resources of info on lxf files? I have only come across fairly basic stuff so far, would love to find a good resource...

# Answer
There's a fairly in-depth discussion on the Eurobricks Digital Designer Forum in the post Understanding LDDs LFXML Schema, where the `transformation` element is defined as:

> Transformation contains 12 comma separated double precision floating point values that represent the first three columns of a 3d transformation matrix and are thus able to handle any linear transformation. It's something that you'll need to learn for yourself but the first 9 entries handle rotation, the last 3 are translation. It's worth noting that the origin of most bricks is at the bottom with the y-axis heading up through the center of a stud, this makes rotations around the axis of the stud slightly easier. Brick width is 0.8, brick height is 0.96 and plate height 0.32. This probably ties in with real world dimensions in some form, but I don't have the details to hand. The double precision floating point format can't necessary cope with precise decimal values as we might expect to see them, therefore you'll see slight deviations from the values given above, eg. -0.79999935626983643 instead of -0.8. Those 0.707 values are 45 degree rotations, they correspond to the sin or cosine of 45 degrees (or PI/4 in radians) and are part of the transformation. Transformations are in world coordinates.

As Philo points out in the comments, the values that The\_Cook queries as "probably ties in with real world dimensions" are indeed the sizes of bricks in centimetres, which means you should be able to transform between systems nicely.

In response to your final goal (building a plugin for 3ds Max) what you're really going to need is a complete set of high-quality meshes - the LDD format works with part models rather than vertices/faces/edges/etc. that 3ds uses. Therefore what you'll probably want to take a look at is a tool to convert from LDD to something like LDraw (you could just use the "Export" function in the LDD file menu), and then use the LDraw model library as your basis for importing into 3ds, or use the features in LDView to export to .3ds (the older, text based file type 3d Studio used before it became "Max").
> 4 votes

# Answer
The 3 last values in the transformation attribute are the position of the brick in 3D space XYZ. Simple.

The interesting part is the first 9 values in the transformation attribute

```
<Rigid refID="0" transformation="0,0,1,0,0.99999910593032837,0,-0.99999988079071045,0,0,-0.39999967813491821,0.40000063180923462,1.2000013589859009" boneRefs="0"/>

```

They are read as a 3x3 rotation matrix (in-depth explanation: Wikipedia Rotation Matrix)

```
[a1 a2 a3]       [ 0  0  1]
[a3 a4 a5]  ==>  [ 0  1  0]
[a6 a7 a8]       [-1  0  0]

```

In this case, this is a single rotation around the Y axis, as the axes directions are:

So if you describe the rotation of the brick as yaw, pitch, roll you can say that this matrix describes a 90 degrees yaw clockwise. A 90 degrees yaw counter clockwise is considered a turn of -90 degrees. (clockwise and counter clockwise are probably not the right terms to use here. I am using to make the description easier to understand)

as long as the brick does a single 90 degrees yaw, pitch or roll, it is simple to detect the rotation axis, because there is a single row in the matrix that remains the same, see section Basic Rotations. In the case of rotating around Y axis, the middle row `[0, 1, 0]` doesn't change.

Rotating around X axis, keeps the 1st row unchanged `[1, 0, 0]`

Rotating around Z axis, keeps the 3rd row unchanged `[0, 0, 1]`

So, rotating 90 degrees around the Y axis is (2nd row is 0, 1, 0 as described above)

```
[Cos90   0   Sin90]
[0       1   0    ]
[-Sin90  0   Cos90]

```

If the transformation is a combination of rotating around 2 or 3 axes, the matrix is not trivial to read and is a matrix multiplication of 2 or 3 of the above matrices with the respective degree of rotation around each axis.

Turning the brick to 90, 180, 270 degrees in each direction, results in values of 0, 1 or -1 for each cell in the matrix. These are the results for the Sin and Cos functions for 0, 90, 180, 270 degrees.

last point to consider:

If you get values that are not 0, 1, -1 there are two options:

1. LDD has a slight miscalculation (This is not a confirmed fact, only my opinion). You can see in the attribute at the top of the post that one of the values is 0.99999... which is basically 1, so it's a 90 degrees turn.
2. You turned a LEGO object in an angle which is not a multiplication of 90 (e.g. hat on top of a head turned 30 degrees clockwise)
> 2 votes

---
Tags: ldd
---


# Question
Title: What kind of mat do you use for running Mindstorm EV3?
Turning EV3 precisely has been a problem. Do you use a certain mat for running EV3 on? Can you tell me what material I need to get the mat printed?

# Answer
> 2 votes
Mats are sometimes used with Mindstorms to create line following bots or for defining more complex tasks.

I can't give great advice on printing a mat for EV3, as I've never done this, but I would imagine that you'd want to be able to print on a large, fairly stiff piece of paper or cardboard. If you're just trying to create a basic line for your robot to follow, you can use a piece of posterboard and then add a line with black tape, markers, paint, etc.

There are several different mats that LEGO has made available for Mindstorms over the years:

https://www.bricklink.com/catalogList.asp?pg=1&catString=246&catType=P&v=1

I believe the most recent is actually the box sleeve in the EV3 kit:

You might want to just purchase one of the officially released mats.

---
Tags: ev3
---


# Question
Title: Help identify this white and medium grey ship section
Can you help identify this ship section from a box of LEGO parts we have now? It looks like it was in an epic battle.

# Answer
> 6 votes
Based on Engine 3X3X6 in white, this is from 7166-1: Imperial Shuttle

Or as Syberion mentioned it can also be 7264-1: Imperial Inspection

Which has almost the same build. The only difference I could find is the color of the 6 x 12 plates on the bottom of the build.

Based on the photo, I think its Dark Bluish Gary so it's 7264.

If you still have the minifigs for this set they will also tell you which set it is, as 7166 had the yellow faced figures and 7264 had the flesh tone figures.

---
Tags: set-identification
---


# Question
Title: What dark green and lime BIONICLE do I have?
If anybody could tell me what BIONICLE this is I’d greatly appreciate it, it’s driving me mad!

# Answer
> 9 votes
My answer totally springboards off of Alexander "*Hawk-Eyes*" O'Mara's astute observation of its suspected authenticity. Nice job Alex.

I looked up BIONICLE knock-offs and got a video that named the brand as "конструктор последний воин", then Google Image searched that phrase for a pic of our Greenie Meanie, and *Voila!*:

Google translates the Russian/Mongolian to:

* "конструктор последний воин":

"Builder of the Last Warrior".
* And this guy is named "ЛИЗОРД":

"Lizord" or Lizard.
* The toy maker is, "1Toy Растем вместе!":

"1Toy Growing Together!".

There seems to be an entire, *Builder of the Last Warrior* line, with at least one dedicated community called *RUSBIONICLE*.

# Answer
> 6 votes
It's not a BIONICLE set or a LEGO set. The pins and axles aren't right for an official LEGO set, so I think this is some random BIONICLE-look-alike set by another brand.

LEGO pins would have a round center, not a flat one:

This axle hole in his hand appear rotated 45 degrees off the LEGO piece that looks like this.

I've never seen a LEGO piece that looked like this:

---
Tags: set-identification, clone-brands, bionicle
---


# Question
Title: Build Instructions for Brown Fedora Hat at LEGOLAND Florida Resort Hotel
When visiting LEGOLAND Florida, I fell in love with this brown Fedora hat that was in the bathroom of our suite at the resort.

I am not familiar with the custom LEGO building community and don't even know where to look for build instructions for something like this, or how to begin figuring out how to build it.

Might someone here be able go get me started?

# Answer
> 4 votes
Hey Victor, I bring gifts!

This *LEGO Digital Draw* file should get you started, as you've asked.

Please consider this a rough draft of your Brown Fedora. I'm calling it rough, because at this early stage, it was just made to look as close to the actual picture with no care for a sensible design flow.

For example, the file may have three stacked 1x4 plates, where there should be a 1x4 brick or corner piece there instead. The abundant plates were used to guesstimate height levels, and left in place because due to the lack of reference material, every level may not be correct.

So, with the *LDD program*, it is possible to generate build instructions, but again, the design flow will not make sense until more data is collected from the field.

**What You're Getting:**

* A ***link to my Google Drive folder*** that contains the LDD file (\*.lxf), and all my collected reference material of pictures and videos. Anyone is welcome to add their two brick clicks to this build.

**Notes and Issues:**

* **From What I Understand:** LEGOLAND Resort is a hotel, outside but within some walking distance to an actual LEGOLAND theme park. So, no one is actually squatting inside the park;).

Hotel guests spend the night in a LEGO themed hotel room. The 5 Themes if available at a particular hotel are: *Ninjago*, *Pirate*, *LEGO Friends*, *Kingdom*, and *Adventure*.
* **Field Research / Resort Locations**: There are multiple LEGOLAND resorts, and it seems like I've traveled the world to find videos and shots of this hat.

So far, only hotels Florida and Malaysia have our brown hat, all other resorts I've searched, California, Windsor, UK, Germany, Japan, and Dubai, all have a gray hat with a totally different design (and clearer pictures).
* **Build Discrepancies Between Images**: Reference images for the top of the hat seems to be missing pieces, or pieces seem to be shifted between images/rooms. One reason I could come up with to explain the discrepancy is a hotel guest pawing the hats, and oops a piece comes off, then it gets reassemble wrong.
* **Lucky Mirror Shortcuting:** We lucked out with the hat being symmetrical (\*Sort of), which means we got away with building half, and just mirrored out the rest. Less work, Yay!
* **(\*Sort of) Symmetry Explained**. You'll notice in some images and shots that the left side of the tan band of the hat lumps out for no apparent reason.

So,I google imaged Fedora hats, and you'll see some of them sport overlapping material pinned down with a swanky feather.

So, I think the designer built the staging for a type of hat accessory.
* **Need more data (01)**. I have no great shots of how the hat connects to the tan mounting block, the actual size of the mounting block, nor how flush the entire piece hugs up on the wall.
* **Need more data (02)**. I have no idea if the designer scooped out the underside of the hat that no guest would ever see, unless some crazy curious guest pulled it off the wall to properly check underneath.

**What Next?**

So, basically the next step to finalizing some great build instructions is to collect more field material.

---

**TO ALL FUTURE HOTEL GUESTS OF ANY LEGOLAND THEMED RESORT HOTEL.**

Hey, please share your family's visit to any of these hotels. We'd like to experience through you, the fun times in your room at a LEGOLAND Resort.

It would be great if we knew:

1. Which Country?:
2. What City?:
3. Which room theme you picked?:
4. What suite number You stayed in?:(Room comparison to control for build discrepancies.)
5. Name of the sculptured object you plan to share with the community?.

We can near replicate anything you've seen, but the level of replication depends on how detailed your pictures/videos are.

* Hold your camera horizontal please (for the rest of my *cough forsaken cough* life);).
* A non shaky, slow paced 360 closeup video of any design would be ideal.
* If you happen to have a loose off colored brick on hand, stick that on it too. Doing so would help out when determining level height.

---
Tags: design, legoland
---


# Question
Title: What sets have been named in a punny way?
I heard speculation that set 40358 "Bean There, Donut That" is the only set that LEGO ever produced where the name of the set is also a joke. Is that true?
Or are there other sets names that contain a pun or double meaning?

# Answer
> 17 votes
A spoof on Indiana Jones and the Temple of Doom:

# 1355-1: Temple of Gloom

# Answer
> 19 votes
Not a great pun, but the 2016 advent calendar was:

# 40222-1: Christmas Build-Up

Sort-of a pun/double-meaning on LEGO being a building toy, and the set being meant to build-up to Christmas.

The 2017 version also has the same name.

# Answer
> 18 votes
# 3852-1: Sunblock (or Sun *Block* as styled on the packaging)

Here "Block" takes on 3 meaning, as part of the word "Sunblock", a pun on LEGO blocks (though I prefer to call them bricks), and a reference to the game play where you try to block your opponents from making another move.

# Answer
> 13 votes
This set name is almost-certainly intended as a humorous reference to Knight Rider:

# 30376-1: Knighton Rider

# Answer
> 11 votes
Bad but probably intentional pun, this set has *dual* bikes that *duel*:

# 8305-1: Duel Bikes

Likewise, there is 4587-1: Duel Racers.

# Answer
> 3 votes
42072 Whack! and 42073 Bash! are not punny but cannot be taken serously either. In Germany, they are called Zack! and Bumms!

---
Tags: sets
---


# Question
Title: Pattern for oscillation with LEGO Technic
I would like to simulate an oscillation movement of 120/100 degrees around a fixed point.

Something like this one:

Basically, I want to rotate a gear around its axis, but only have a partial rotation and then have it return back.

# Answer
What you're looking for is reciprocal motion, or to convert rotation motion into linear motion (and then back to a limited rotation).

Building out the key parts of the fan head you have the following setup (using fairly standard technic pieces:

1. Drive the smaller cog normally, this will rotate 360° as normal.
2. The driving rod will only move as far as the limits of the smaller cog - from the side you can see that this appears to be only going forwards and backwards.
3. The larger cog will be driven forwards a few degrees and then be pulled backwards as the driving rod is pulled back in return.

Adjust the distance between the gears and the size of the gears as you require. If you need a larger gear in (3) you could replace the gear with one of the liftarms with an axle hole rather than circles, etc.
> 13 votes

---
Tags: technic, building
---


# Question
Title: How to build a steerable remote-controlled vehicle with just 1 motor?
In WeDo 2.0 set **there is only 1 motor**, which can be remotely switched on and off by using the iPad app (by writing a Scratch program).

Also motor rotating direction can be toggled remotely.

As an inexperienced LEGO builder I wonder if it is possible to **build a remote-controlled vehicle out of 280 WeDo 2.0 pieces, which would be steered by changing the motor rotation direction**.

I am thinking of having 2 wheels with wide tires in front the vehicle, connected to the motor.

And having a single *caster wheel* with narrow tire at the back of the vehicle, not connected to the motor.

The *caster wheel* would roll straight, when the vehicle drives forwards.

But when driving backwards, it would snap to a certain angle.

**UPDATE 3:**

Found a picture for such a *caster wheel* in the LEGO Technic Idea Book by Mr. Yoshihito Isogawa:

**UPDATE:**

I have followed Aaganrmu's suggestion (thank you) and have tried to build a simple vehicle using *ratchet* instead of *caster wheel*:

https://www.youtube.com/watch?v=uqYQ79SdBpY

Unfortunately, it doesn't work well. There is too much friction - on the axles of all 3 wheels and on the rubber band.

I wonder if experienced LEGO builders can propose a better vehicle out of WeDo 2.0 parts than mine:

And I feel that my Scratch program can be improved too, since it is not very responsive to user input (when touching the 4 green arrows):

**UPDATE 2:** Got a nice suggestion at Eurobricks forum:

(video authored by Mr. Yoshihito Isogawa again).

**UPDATE 4:**

Here a good WeDo 2.0 model with steering:

https://www.youtube.com/watch?v=Q9sd4MxW4YY

# Answer
> 13 votes
This can be done without a caster wheel as well:

Start out with a three wheeled vehicle, with two wheels in the front and one smaller wheel with less traction than the front wheels in the back. All wheels need to be fixed.

One of the front wheels is attached to the motor. This might need to have some gearing to get an appropriate speed.
The other front wheel is unpowered but can only rotate forward by adding a ratchet:

The back wheel is unpowered.

Driving forward the vehicle will more or less move straight, guided by the rear wheel.
Driving backwards the ratchet will engage, stopping one wheel. The vehicle will now turn.

# Answer
> 6 votes
In WeDo 2.0 app "LEGO® Education WeDo 2.0" there is a complete project `12. Steer` that is exactly about that

When it drives forward it goes in straight line, when it drives backward it then turns to one side.

There is full build instruction in the app.

I've also added distance sensor and made it fully autonomous - whenever it sees obstacle it goes back, turns, changes direction and continuous driving

# Answer
> 4 votes
I designed some WeDo 2.0 models that can drive and steer using just one motor. This one uses a system of gears to alternately drive the left or right wheel of a differential drive robot, depending on the turning direction of the motor.  You can find the complete building and programming instructions here: https://robotics.benedettelli.com/lego-wedo2-zigzag/

Another idea is making a steering vehicle similar to the one shown in the WeDo App, and involves directly driving a pair of wheels, and having two steering wheels that act as a caster with limited swinging movement. That way, when the motor pushes the vehicle forward, the steering wheels are forced to stay straight and the vehicle goes straight; when the motor drives the vehicle backwards, the steering wheels will be free to rotate a bit, and the vehicle will steer.  You can find the complete building and programming instructions here: https://robotics.benedettelli.com/lego-wedo2-car/

# Answer
> 3 votes
One motor and a caster wheel will give you two degrees of movement but will not be steerable. If you can build a differential, then drive two wheels with the motor.

If you have limited gears, then drive one wheel, have an idler wheel and a caster or simple skid arrangement.

You can get more interesting behaviour by having a bumpbot, that simply reverses the motor when it detects an obstacle.

See the Wikipedia article on casters, but there is a strong relationship between wheel diameter and how high the caster should be. And the surface area of the wheel and the mass of the load drive the how easy and fast things swivel. It's an interesting engineering trade-off, and I've never been able to make a perfect caster, even with lots of Technics parts. I now have reasonable respect for those people who design the casters into the everyday things we use without considering how difficult these trade-offs can be. (As in, it isn't an intractable problem, but the problem domain is extremely sensitive to small changes.)

Start with a skid first, and an easy, smooth surface to see if you get the basic behaviour you want.

Finally, you may get more interesting behaviour by ramping or stuttering motor direction and speed a little on obstacle sense. This is a cheap way to introduce some more randomness into the system.

Even more finally, you might want to get your hands on some LEGO Ball Casters, which I didn't know existed until this very moment.

---
Tags: motor, remote-control, vehicle, steering, wedo
---


# Question
Title: Get robot to face perpendicular to nearest object, using the ultrasonic sensor in NXC?
I have an ultrasonic sensor attached to a motor so that the sensor can rotate. Right now it stops once it scans a value less than 65 cm. What I want it to do is to scan its surroundings and then face the ultrasonic sensor perpendicular to a the closest object.

```
task findWall()
{
     OnFwd(OUT_C, 30);
     until(SensorUS(IN_4)<65);
     Off(OUT_BC);
}

```

# Answer
> 1 votes
I like your username. I'm not exactly good at NXC either, but I'm experienced in C and Java. So here's some *pseudocode* that should get the job done. This will rotate the scanning motor 180 degrees, while remembering the closest object it's seen, and then rotating that motor back to point towards the closest object. You will need to change the functions to correspond to the actual NXC functions.

```
int closestObjectDist = 100; //variable records the closest object's distance
int closestObjectAngle = 0;  //variable records the angle pointing to the closest object
int currentAngle = 0;        //variable to hold the scanning motor's current angle.
int currentDistance = 0;     //variable to hold the sensor's current distance reading

resetScanningMotorAngle();   //reset the scanning motor's angle to 0.
turnScanningMotorOn(10);     //start rotating the scanning motor, slowly.

while(currentAngle < 180)    //repeat until the scanning motor has rotated 180 degrees
{
    currentAngle = getScanningMotorDegrees();  //get the motor's current angle
    currentDistance = readUltrasonicSensor();  //get the sensor's current distance

    if( currentDistance < closestObjectDistance )  // Here's the important part:
    {                                              // When the sensor reads a distance that
        closestObjectDistance = currentDistance;   // is the smallest distance yet,
        closestObjectAngle = currentAngle;         // record the angle and distance.
    }
}
                                            //now we have the closest object's angle stored!
rotateScanningMotorTo(closestObjectAngle);  //rotate the motor back to the recorded angle.

```

This code assumes that the robot scans in a 180-degree arc, but you could easily just change the 180 to 360 to scan in a full circle.

After the loop, you can add or subtract 90 degrees to closestObjectAngle to make the motor point perpendicular to the closest object instead of pointing AT the closest object.

Ask if you have any questions!

---
Tags: motor, nxc, sensor-ultrasonic
---


# Question
Title: How do I delete custom images I made in my computer?
I created a custom image for a test, and everytime I download the program to my brick, the image shows up in the folder despite me not using a display program. How do I fix this?

# Answer
You should be able to go to the project tab (1) - it's the one with the wrench icon - and delete any unneeded items. Just select the item (2) and click the *Delete* button (3).
> 4 votes

---
Tags: ev3, ev3-g
---


# Question
Title: Identifying Parts Used For The Escape Hatch of Sariel's Tiger XL Model
I am working on a similar model of Sariel's Tiger XL in prep for my own designs of a few other German WW2 tanks, and need some help identifying a part or two.

Does anyone know what are the two parts on the left image that stand in for the escape hatch? One looks like a spanner, and the other one behind it is circular.

# Answer
***First three from what we can see...***

1. Part: 4735 Bar 1 x 3 with Clip and Stud Receptacle (Robot Arm).

2. Part 2958 Technic, Disk 3 x 3.

3. Part: 75c03 Hose, Rigid 3mm D. 3L / 2.4cm.

***Last two hidden from view...***

4 & 5. Part: 4085d Plate, Modified 1 x 1 with Clip Vertical - Type 4 (thick open O clip).

I can't see, but I can imagine two crossed vertical 1x1 clip plates, pierced by the flex tubing to hold up the robot arm.

***Sing! Now, build it out. Now, build it out. Now, build it out...***
> 11 votes

# Answer
This is actually made of three parts as far as I can tell.
> 4 votes

---
Tags: technic, part-identification, building, piece-usage
---


title: Was there ever cadmium in LEGO bricks?

text:
# Question
Title: Was there ever cadmium in LEGO bricks?
I remember a rumour from my youth in the late seventies / early eighties, that there was supposedly cadmium in older (relative to that time) LEGO bricks.

Searching for `LEGO cadmium` yields quite a lot of hits, but so far, nothing conclusive.
I also note that LEGO has never recalled any old bricks, which I admit would be next to impossible: how would the general public be able to distinguish between older and newer bricks?

**Has cadmium ever been used in LEGO bricks? If so, in what quantities?**

How about other toxic metals?

# Answer
I asked Gary Istok on your behalf in this Brickset Forum thread, who is an expert on LEGO's history. He said the following:

> When LEGO replaced the Cellulose Acetate bricks circa 1963 with ABS plastic for non-trans parts, and polycarbonate for the trans ones, they had a problem with the red and yellow parts. For some reason (I'm not a chemical engineer)... red and yellow ABS parts were more difficult to color to TLG standards. So Bayer and Borg-Warner (the chemical companies that produced the ABS and other plastic pellets worldwide) added Cadmium, a heavy metal, as an additive to those 2 LEGO colors to help in the coloring process.
>
> Although Cadmium will not leach out of the LEGO bricks of that era (kids could safely chew on those LEGO parts), the longer term landfill issues of Cadmium laced LEGO getting into the ground, did become an issue with environmentalists. So TLG had their plastics makers Borg-Warner (for USA, Canada, Britain, Ireland and Australia) and Bayer (for continental Europe and Asia) work on removing the cadmium from the red and yellow elements of that era. I don't know the chemical specifics of that action, but by 1973 LEGO parts were Cadmium free... and have remained so.
>
> Next question.... can you tell Cadmium parts (1963-72) from Cadmium free parts? Generally yes... but it's easier for red bricks, which are a darker red color with Cadmium. Yellow LEGO parts with Cadmium are also a darker color, but the difference between Cadmium and Cadmium free yellow parts is less noticeable... especially with used or dirty yellow elements.
> 11 votes

# Answer
Even in early 1980s there were some patches having Cadmium. I should link to the study but lost it now.

Here is somewhat proper reference:

https://www.thesun.co.uk/news/5436922/second-hand-plastic-toys-including-lego-could-harm-children-with-toxic-chemicals/

Eating is something to avoid. Hand-to-mouth (hand skin licked) behaviour is not as fatal.
> 2 votes

---
Tags: history, safety
---


# Question
Title: Can you identify what sets this partial build and bag of LEGO elements come from?
We got this big box of Lego bricks, and we don't have the manuals, please help!

# Answer
> 2 votes
Welcome to Bricks.SE! The bag numbered 2 is from set 9494 Anakin’s Jedi Interceptor.

This is all based on the included Windscreen 10 x 6 x 3 Bubble Canopy Double Tapered with Light Bluish Gray Jedi Starfighter Pattern which only appears in this set (there is an older version of this piece but it is too old to have been included in the bag pictured, which LEGO didn’t start using until 2011).

The second picture contains a child’s own creation out of various pieces, including a Windscreen 6 x 6 x 3 Canopy Half Sphere with Dual 2 Fingers and SW Tie-Fighter Pattern.

This piece also comes only in one set, namely set 9492 TIE Fighter. Both sets are from 2012.

---
Tags: set-identification
---


# Question
Title: What is this 2x4 brick with a 2x3 rounded plate with hole attached?
I found this LEGO brick and have no idea what it does, it’s name, or which set it is from. It is a 2x4 brick with a 2x3 base plate with a rounded end and a hole in it.

Can anyone tell me about this brick?

# Answer
It's a magnetic base that minifigs are attached to.
> 6 votes

---
Tags: piece-information, part-identification
---


# Question
Title: Part identification: 40 tooth gear from The LEGO Movie
While watching clip of the LEGO Movie, I found a strange part:

Slightly earlier in the video, its part number is shown as 3649.

But it doesn't match the 40t gear I know nor the pictures on bricklink.

Is it an error from The LEGO Movie or a variant I don't know?

# Answer
From this image, you can count the teeth well enough to determine there are actually 60 teeth, not 40:

This does not appear to be a real part.

It also appears you aren't the first to notice this. Jim Brickkeeper had created a ShapeWays model based on this movie piece which I found while searching for LEGO 60 tooth gears. It's no longer available, but it might be possible to contact them and see if there is another way to get it made.

According to Matthew Ashton this piece was planned for use in the set, but due to budget changes had to be cut, and has not yet been produced.

> For each project we are assigned a certain budget and a certain number of moulds we can create for new pieces. It was our intention with the Movie to make all Characters and Vehicles toys 100%, movie accurate. However in this case the directors really wanted the back wheel to be bigger, so we designed the piece for them, but then later had to make a compromise on one of the models as we didn't have the budget for all the tooling. Lord Business's design had become more complicated and required more moulds than orginally planned.we had to get him 100% correct, so we decided to alter the Super Cycle as we felt it would be less noticeable, at that point we weren't aware that it's part No. would be called out
> 15 votes

---
Tags: part-identification, gears, the-lego-movie
---


# Question
Title: Where to find pictures of undersides of bricks? (possibly Lego clones about 25-30 yrs ago)
I am trying to identify which non-Lego bricks I might have played in the past. Don't recall the names but I can probably recognize them from photos if I see them again

For example, I remember some 2x4 bricks having two horizontal lines across the center (on the underside).

# Answer
> 1 votes
Could it be ***BRIX BLOX***? Came across these on *eBay* and thought about you...

---
Tags: part-identification, clone-brands
---


# Question
Title: Can you please identify these two assemblies, dark grey, dark red, yellow, and tan plus Technic treads with large orange pieces?
Set assemblies 1

Set assemblies 2

# Answer
> 2 votes
In the top image you have parts of 7656-1: General Grievous Starfighter and 7669-1: Anakin's Jedi Starfighter.

In the second image you have parts of 7706-1: Mobile Defense Tank

---
Tags: part-identification, set-identification
---


# Question
Title: How to MOC the Rough Terrain Crane 42082
I recently got me the Rough Terrain Crane 42082 and had lots of fun while assembling it. I find it a decent Technic build and worth the price. Still I find it under-motorized. I would like to drive and steer it. Do you know where I could find MOC instructions to modify and motorize the crane?

# Answer
There are building instructions in this video of a fully motorized version: https://youtu.be/mmKw\_GBFGs0

And here is a demonstration by the same builder how it all works: https://youtu.be/RzBaDTpG2Ss
> 2 votes

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Tags: technic, moc
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# Question
Title: Are there any LEGO "MacGyvering kits" for the on-the-go LEGO fan?
I keep a small box of electronic parts in the car, for times when I get an idea I want to try out, or have a quick gizmo that I need to solve a problem. I also have a box of mechanical parts, like strings and pulleys and weights, that I'll use sometimes. When I hang out with my engineering friends, we'll often come up with ideas that we can quickly build and test. It seems that I should put together a similar set of LEGO parts.

I'm looking at a target volume about 3200 cm³ (200 cubic inches, 3.4 quarts), including space for organization. No individual element should be larger than 140mm×230mm (17×23 studs). The most important goal is versatility. I'm mostly orienting this towards engineering tasks, but may also throw in a few minifigs for decorative builds.

The best idea I currently have is to use the Creative Suitcase, and augment it with parts from one of the smaller Technic kits that's almost entirely general-purpose Technic parts, like the Compact Tracked Loader.

It seems likely that people have built similar "on-the-go" kits, or have their "hotlist" of LEGO parts that are always at hand when prototyping. Any thoughts on the matter?

# Answer
It seems like you have the parts in mind, but really just need a case.

I have used fishing tackle boxes and artist supply boxes, but the compartments were too narrow.

**Pros**: Versatile, cheap, stackable, configurable. You can use the removable compartments as parts trays during builds. You can find them in various colors at the major discount retailers in the U.S.

**Cons**: No handle. Not durable. If you drop or step on them, the hinges will crack.

**Dimensions**

* 13 3/8" L x 10 3/4" W x 2 1/2" H
* 34 cm x 27.3cm x 7.9cm

Listing at the Sterlite website
> 2 votes

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Tags: sets
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# Question
Title: Can anyone identify what kind of block these hinged blocks are?
They all link together. I added a normal Lego brick to compare size.

I have had no luck with Google.

# Answer
Woah! I haven't thought of these in years... Flashback to FLEXIBLOCKS!!!
> 5 votes

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Tags: part-identification, clone-brands
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title: Importing 3ds file in ldraw (LeoCAD)

text:
# Question
Title: Importing 3ds file in ldraw (LeoCAD)
I designed a model in LDraw/LeoCAD and exported it as `.3ds` file. I thought that I can import `.3ds` file to edit it later. Now I want to edit the model but I don't see any option to import the `.3ds` file in LeoCAD. I tried my best to open it but useless.
How can I open a `.3ds` file in LeoCAD?

# Answer
.3DS is a 3D image file format, a rendering of what you designed in LeoCAD. All information necessary to recreate your build (i.e. what bricks to use) will be stripped from it. I suppose that theoretically this information can be recreated for small builds, but for medium-sized to large builds, this will simply be infeasible. Hence I think it quite unlikely that it's possible to import .3ds back into LeoCAD.
> 2 votes

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Tags: cad, ldraw
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# Question
Title: Please help identify this LEGO set with large black curved elements with orange stickers
Can you please help me identify this set.

# Answer
These are parts from 8058-1: Guardian of the Deep

except the Black Aircraft Fuselage Curved Forward 6 x 10 Bottom with 3 Holes.
> 5 votes

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Tags: part-identification, set-identification
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# Question
Title: Lego Set ID with lime green and grey pieces?
I need your help to identify this set.

# Answer
> 8 votes
These are parts from

8192-1: Lime Racer  besed on the Slope, Curved 2 x 2 Lip, No Studs with 'RUN' and 'V8' Pattern Model Left (Sticker) - Set 8192

and parts from

7052-1: UFO Abduction  based on the Slope 33 3 x 2 with Alien Insignia Pattern (Sticker) - Set 7052

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Tags: part-identification, set-identification
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# Question
Title: Lego Set ID for white curved pieces with blue Police stickers?
I got another police set but can't find directions.

# Answer
The parts with "Polizei" are from the 7741 Police Helicopter set.

Other parts are from the 7286 Prisoner Transport set (parts with "Police" and "03").

The license plate is from the Fire Truck of the 7206 Fire Helicopter set.
> 1 votes

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Tags: part-identification, set-identification
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# Question
Title: Part Identification: Black Bionicle Foot Piece?
I saw this piece used as a foot in someone's MOC and I can't figure out what it is. It kind of looks like a Bionicle foot but it doesn't match any that I know of. Pretty sure that the axle going through it in the picture is separate and not part of the piece. Can anyone help me identify it?

# Answer
It's a "Sports Hockey Skate" mostly from LEGO Hockey although it has appeared in some BIONICLE sets also.
> 4 votes

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Tags: part-identification
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# Question
Title: Is the EV3 compatible with a 3rd party I2C gyroscope?
The only detail I've found so far is that the pull-up resistor should be 82k ohm. I'm wondering If I could just get something like this Adafruit Gyro/Accelerometer and just hook it up to the SDA and SCL pins of the EV3 and use it like the Lego brand sensor with minimal modification.

# Answer
> 1 votes
Yes, Mindstorms is incredibly hackable. You can use whatever 3rd-party analog, I2C, or UART devices you want with the EV3 brick. According to the hardware developer kit documentation:

> The EV3 platform supports the same level of I2C communication as MINDSTORMS NXT. This means that system support a maximum of 9600 bit/s and maximum 32 bytes communication buffers. All I2C communication is running within software drivers. External devices are required to include pull-up resistors on both pin 5 and 6 on 82K ohm. If multiple sensors are used on the same bus the total impedance needs to be adjusted accordingly.

Obviously, the standard Lego programming software will not be able to utilize custom devices, but pretty much any 3rd-party firmware will allow sending custom I2C read/writes.

# Answer
> 1 votes
As MindS1 mentioned, I2C on the EV3 is a bit limited, so it really depends on what device you are connecting. There isn't really a way to tell if a device will work or not besides just trying it out. Even if it "meets the specs", there can still be timing issues that cause problems.

Dexter Industries has a nice blog post about connecting EV3 to an Arduino via I2C. This includes a block they created for the official EV3 programming software that does generic I2C communications. One limitation is that although you can read up to 32 bits at a time, you can only write at most one byte at a time (this is a limitation of the EV3 firmware, not the Dexter Industries block). So if a device requires longer write messages it definitely won't work. Otherwise, as already mentioned, you will just have to try it and see what happens.

The ev3dev 3rd-party OS for EV3 has more robust I2C handling since is uses the standard Linux I2C interface. For example, you can write a program in Python like this.

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Tags: ev3, mindstorms, 3rd-party
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# Question
Title: Can you identify the set these white vehicle elements come from?
We got this big box of Lego bricks, and we don't have the manuals, please help!

# Answer
I'd hazard a guess for *3661-1 Bank & Money Transfer*, based off your Minfig, which shows up in only one set.

Free build instructions *here* at LEGO.com if you have all the pieces to this set.
> 3 votes

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Tags: part-identification, set-identification
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# Question
Title: Which set is this with a white truck and camper trailer?
I’ve been searching online for quite some time to find this set number, name, and the instructions, but I’ve had no luck. I’ll be passing it on to a youngster in the family and after it’s promptly destroyed I was hoping to have the instructions for him. Thanks!

# Answer
I believe this is the set:

https://www.bricklink.com/v2/catalog/catalogitem.page?S=6345-1

I searched on the vehicle roof piece, only 48 sets have it in white...

The instructions for this part of the set are pages 3 through 9 and are available on Peeron.
> 7 votes

# Answer
**Set Number:** *6345*.

**Name:** *Aerial Acrobats*.

**Instructions:** We have at least ***3 options***: Two options are for free digital. One option is a physical purchase.

* **Option 1**. *Here* are free online digital instructions for this set.

* **Option 2**. Skip over to *YouTube* and *watch a speed build of this set*. In settings, (gear icon), you can slow the playback speed of the video and easily glean an understanding of the build.

* **Option 3**. It is possible to download and keep *YT* videos, but...if you still want to keep things traditional by wanting a physical hard copy for said youngster's future inheritance, then head on over to *Bricklink*, where for *under $10 bucks*, you should be able to purchase the actual instruction booklet for this set.
> 4 votes

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Tags: set-identification
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# Question
Title: How to convert LEGO base plate to a DUPLO base plate?
How can I convert a regular LEGO base to a DUPLO base? I have a table that cannot be changed and it has built-in LEGO baseplates, but I need it to be 100% DUPLO compatible. Any LEGO to DUPLO baseplate converters?

# Answer
The table IS already *cross* compatible, even though it doesn't look it. The tabletop or LEGO baseplate is cross molded for DUPLO pieces to fit and lock in on top of the regular LEGO baseplate.

***PART ONE: THE PICTURED PROOFS...***  So, let's imagine the top of your table is my unopened gray baseplate.

We'll use a DUPLO Cock-A-Doodle-Doo for an example DUPLO model.

Sorry, but I don't want open my baseplate just yet, so in the next four shots we'll use these green plates to show the cross interlocking magic of LEGO and DUPLO.

***PART TWO: THE WHAT IFs...***  Now, I did say the magic was *cross* interlocking, so... *WHAT IF* your tabletop *HAD* started off DUPLO and we wanted it to be, in our minds, 100% compatible with regular LEGO.

You see, it is compatible, again, it may not look it at first glace, but as we can see using these White 2x4 LEGO bricks with a Bright Yellow 2x2 DUPLO brick things are indeed cross compatible.

I'm gonna get uber geeky here, but the harder to imagine negative space inside the White 2x4 LEGO brick interlocks beautify with the easier to see studs of the 2x2 Yellow DUPLO brick.

Well, hey! Hoped to have saved you time, money and effort in fabricating a new table. Later!
> 6 votes

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Tags: piece-information, compatibility, duplo
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# Question
Title: How can I get the EV3 to control an ordinary motor with PWM?
Looking at the hardware developer pdf, it looked like the EV3 should output a PWM signal with a duty cycle corresponding to power level. It does, but only for 100ms and only on pin 1.

Is that how the signal should look or is it because the EV3 know there's no motor attached?

I'd like to do this all in hardware if that's at all possible.

# Answer
> 1 votes
The hardware solution is to simulate the motor circuit on pins 5 and 6.

There is a YouTube video by TechnicRobot that shows one way to do this.

I'm not sure I understand completely the logic behind this wiring. Personally, I would just connect pin 6 to pin 3 directly and connect pin 5 to pin 3 using a 3.3k resistor so that it exactly matches one of the 4 possible states of an EV3 Large motor.

When you do this, the EV3 will detect your motor as an EV3 Large Motor. However, you shouldn't use the Large Motor blocks in the EV3 software. Since this hardware hack won't provide a position feedback signal, those blocks won't work correctly. Instead, use the Unregulated Motor block (one of the blue "advanced" blocks) to control the PWM duty cycle.

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To get a PWM signal on pin 2, simply run the motor in reverse. It is not possible to get a PWM signal on both pin 1 and pin 2 at the same time using the official LEGO firmware.

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For anyone looking for a software solution rather than a hardware solution, there are some similar questions that should be helpful:

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Tags: ev3, motor
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# Question
Title: Any ideas how to separate these lobed gears and lightsaber pieces?
Any help please? I've got these two pieces stuck together and not sure what to try! I don't want to break the pieces...

# Answer
> 5 votes
A possible solution I frequently use in such cases:

Cover the transparent bar into something soft, e.g. a few layers of paper tissue and fix that part in a vise or a pliers. Tissues will prevent the tool from leaving marks on the bar. When the bar is sufficiently fixed you can simultaneously pull and carefully rotate the yellow piece back and forth until it comes off. You can use some soap to make it easier.

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Tags: piece-information, disassembly
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# Question
Title: Can you help me identify this poly bag #4 with many grey pieces?
We got this bag in a free box and don't know what it is!

# Answer
I'll be happy to help out, my Friend. It comes from *Set #75103 First Order Transporter*.
See ya around Space Cowboy!
> 5 votes

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Tags: part-identification, set-identification
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title: What came first? Print or sticker?

text:
# Question
Title: What came first? Print or sticker?
Recently I learned that there seems to be no strategy in the LEGO design about when to use stickers and when to use prints in a given set. My question is what LEGO used first to decorate bricks: Prints or stickers?

First I thought, it must have been stickers, but then I found the 360 Ambulance from 1971 with a 1x2 brick with a printed red cross symbol.

# Answer
The BrickLink Catalog, which is the most comprehensive database of LEGO parts ever made, lists the first official stickers from 1971. They were used in the Homemaker sets to decorate furniture, etc. List of LEGO Stickers Sorted by Year

Interestingly, at the same time (early '70s), the large Homemaker figures had printed faces, but the first minifigures (with no movable legs and arms) had blank faces, and stickers for their torsos.

To find the oldest printed piece, I went through the BrickLink Color Guide, and looked at the colors that have been produced the longest (since 1950). I checked each of these colors, sorted the results by year released, and looked for the first appearance of printed elements.

The first printed pieces that show up are a large selection of street signs and lettered signs produced in 1955. They were mostly printed on white elements, but there are also some printed yellow and red pieces through the 1950s. First White Printed Parts Sorted by Year

In summary, the first decorated parts were printed, but LEGO has been using a combination of stickers and printed pieces since the early 1970s. While this has been the cause of frustration for LEGO fans and collectors who prefer printed parts, it is actually in line with the policies of other toy makers. Mega Bloks (now Mega Construx), Kre-O, Oxford, Playmobil, etc. also have been using both stickers and printed elements in their toy lines.

It's also interesting to note that in the 1970s and 1980s, LEGO released ideas books with sticker sheets, which allowed children to customize their minifigures and other pieces in creative ways. Stickers were considered cool back then, and were extensively used for customization. Nowadays, stickers are viewed more as a sign of a company being cheap and lazy.

It's worth looking at the history of stickers and printed parts through the years and through toy lines, and how they were perceived and used by consumers (especially children). This is just my personal observation, but I believe the recent preference of printed parts has to do with collectors getting interested in children's toys and demanding what they perceive as higher quality. Children who are old enough to manipulate stickers, generally prefer the customization options stickers provide.
> 10 votes

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Tags: piece-information, history, stickers
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title: How to make an exact 16 degree turn?

text:
# Question
Title: How to make an exact 16 degree turn?
Does anyone know how to make an exact 16 degree turn with a LEGO robot?

# Answer
This is actually a surprisingly difficult task. If you search for similar questions over on the Robotics stack exchange, you will find very smart people who can't even get it right with thousand-dollar localization solutions and graduate-level control theory.

If you have a Gyro sensor like Michael suggested, you're on the right track. You can probably get close to 16 degrees with that.

If you don't have a Gyro sensor, you can use the motors' built-in rotation sensors. If you drive the motors in opposite directions, the robot rotates around the point halfway between the wheels, and the formula is:
Where:

* r\_wheel is the radius of your robot's wheels
* theta\_wheel is the angle the wheel has to move
* r\_robot is the radius of the robot (half of the distance between the two wheels)
* theta\_robot is the angle you want the entire robot to turn, in this case 16 degrees.

So measure the radius of the wheel and the robot, plug in 16 degrees for theta\_robot, and solve for theta\_wheel. Then drive one motor forward theta\_wheel degrees, and one motor backward theta\_wheel degrees (simultaneously).

Bonus points if you make a MyBlock to have the EV3 do the calculation itself, for any desired theta\_robot.

Actually even if you do have the gyro I would recommend trying both to see which gives better results for your specific situation.
> 7 votes

# Answer
Do you have a gyro sensor on your robot? I'm assuming you're using an EV3 set, and the Mindstorms programming environment.

If so, reset your gyro sensor, and then insert a loop block attached to the gyro sensor. Set the loop settings to \>= 16 degrees, and insert a tank move block into the loop. The motor should be set to 'on', with wheels going in opposite directions; the speeds should be relatively low to more accurately stop at your chosen degree setting. After the loop, be sure to insert a stop, or the robot will keep rotating.

m.
> 3 votes

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Tags: programming, motor, robotic
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# Question
Title: What are some helpful techniques for applying stickers?
It can be tricky to place small stickers accurately on small parts using adult-sized hands. The best technique I've found so far is to remove the sticker and stick it on the corner of the sticker sheet so that I can position the sticker above the part without my fingers getting in the way. Still, though, it can be difficult to center the sticker perfectly, and when the margin between the sticker and the edge of the part is small, tiny inaccuracies are easily noticeable.

What are the most effective techniques for applying stickers accurately?

# Answer
For a rectangular sticker on a rectangular surface, I usually try to center it between two sides and align it along the top. This does cause the problem of centering the sticker up and down.

If I really care about the proper alignment, I use the end of a small knife blade to place the stickers properly. Just stick a corner of the sticker to the tip of the blade, align and stick. This has the added advantage that when you begin to place the sticker, the knife is still underneath and will allow you to remove it and try again if you miss.
> 15 votes

# Answer
Another way is to stick a single side of the sticker to the piece, then give it a little tug without ripping it to make sure it's flat and has no wrinkles. Then apply the middle and other end.
> 4 votes

# Answer
While building the Ghostbusters Firehouse Headquarters, I used tweezers to place the stickers. This let me reposition it if it wasn't quite in the right spot, but had already started sticking to the element.
> 4 votes

# Answer
The LEGO brick separator, spanner and crow bar have thin wedges on the end, which makes the sticker a bit easier to line up, rather than position by hand. I have heard some people talk of placing a drop of water on the brick, allowing a moment of slide before the sticker attaches firmly (but need to attempt it for myself).
> 4 votes

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Tags: building, stickers
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# Question
Title: How to lubricate the 4.5v train motor for set 7722?
How I can lubricate the 4.5v train motor on my #7722 train set? It squeals.

# Answer
> 6 votes
Undo the 2 screws at the top and then take of the top cover.
You can now take the actual motor out of the casing. It just sits loose in there.
Then you can undo the 2 screws in the bottom to free the metal block with the plastic gears. It is most likely those gears that cause the squealing because of dust/dirt that got into them.

I would recommend to clean them first using a soft brush. (Paint-brush works well). You can stick an axle through the bushings and turn the gears manually or rotate the big gear shown at the top with your finger. Just let the gears run against the tip of the brush.
Don't stick the brush in too deep! You don't want the hairs of the brush to get caught in the gears!

Then lubricate with a little bit (a few drops is enough) of plastic safe oil. the movement of the gears will spread the oil around eventually when the whole thing has been put back together and is running again. (This might take some minutes of running though. Don't expect the noise to go down after 5 seconds!)

Don't use WD-40. It will degrade the plastic !!!

You should NOT lubricate the actual motor itself. Some of the oil you put on the gears will eventually make it into the electric motor and that should be enough.

# Answer
> 0 votes
Here's a video of someone lubricating an engine of similar size of the x482 engine inside x469b : https://www.youtube.com/watch?v=L\_0SKz8aHRk

I used this technique (if the video disappears: a tiny amount of lubricant directly on the rotating bit of the engine that the axle with gear sticks out of, so between the metal gear that's fixed to the axle and the engine housing) with exactly the same effect as in the video: the high pitched squeaking noise disappears completely, immediately. I probably used the wrong oil, I think it's best to also do this with something that won't damage the plastic, but on the other hand I doubt very much will make it's way out of the engine and the metal parts surrounding it onto the plastic gears or housing.

Note that you can test first if the engine is the noisy bit by holding the power to the contacts at the end of the engine after getting it out like in the picture in Tonny's answer.

Too bad I don't know how to open my 6216m engines to do the same thing there.

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Tags: trains, motor
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# Question
Title: How could I make a golf robot from a LEGO NXT kit?
I want to make a golf robot. It will be placed straight in line with the ball. It will approach the ball and swing.

The part where I get confused is how to get it to swing in a left-right motion when the motor attached is heading towards the ball.

I want to know how to build it!! I tried following some images I found online but there weren’t any details about the design.

This is what I would like to build. I'm curious about the motor and the golf swing part!

# Answer
This model uses **gears** to do 2 things:

* Change the direction of motion:
    1. The motor turns an axle, on which a gear is attached (partially hidden black disk in the picture).
    2. The first two gears shift the rotation out in front of the motor.
    3. The next two knob wheel "gears" turn the rotation 90 degrees, resulting in the golf club motion you see in the picture.
* Increase the speed of the golf club:
When you combine gears of different sizes you can change how fast or how strong the output is.
The first two gears have 36 teeth and 12 teeth, in that order. This makes the golf club move *3 times faster* than the motor.
If you were to swap the gears, putting the small 12 before the 36, it would make the club 3 times *slower* than the motor.

You can find building instructions here. This model was designed to be built with the NXT Education Base Set. If you have the normal NXT retail set, you won't be able to follow the instructions exactly; there will be a few missing pieces, but it should still be pretty easy to find suitable replacement parts from what you have in the kit.
> 1 votes

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Tags: mindstorms, nxt, robotc
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# Question
Title: Why does the Duplo bathtub piece have an odd height?
I have recently come in touch with the Duplo bathtub piece.

While it is mainly a bathtub whose bottom is shaped in such a way that it can be placed on Duplo studs, one of the piece's sides also features two studs on top. This suggests the bathtub can be integrated into other constructions such as walls, similarly to other furniture pieces such as the toilet piece.

Curiously, though, the bathtub does not seem to have a height that fits with other Duplo bricks. It is taller than a Duplo brick, but not as tall as 1.5 Duplo bricks (or a Duplo brick plus a Duplo plate).

**Why is that?** Is there any way this non-standard height can be advantageous, just like e.g. the Erling brick's reduced depth that allows for sideways *and* upright integration? Can I combine the bathtub with its odd height with anything else at all?

---

*One of our first ideas was to have the slide end in a bathtub. But with the bathtub's non-standard height, building a support for the slide is tricky.*

# Answer
Although we probably won't get a definite answer to why this decision was made, unless a LEGO part designer steps in to answer the question, here are some things to consider.

The LEGO DUPLO bathtub, toilet, and sink all have two studs at the end. Looking through all the sets these pieces appear in, the studs are used for attaching accessories, like a shower head (for the bathtub), mirror (for the sink), or printed bricks with various bathroom accessories. They are not made to be integrated into a wall (at least not as a primary feature).

Even though the toilet and sink are 1.5 LEGO DUPLO bricks tall with two studs, I can find very few examples when this was taken advantage of by incorporating the pieces into a wall. In the vast majority of LEGO DUPLO sets, the bathtub, toilet, and sink are freestanding next to a wall, and often next to each other. To mimic realism, the bathtub needed to be shorter than the sink, but tall enough to fit a figure - thus the odd height.

In the case of LEGO DUPLO accessories, furniture pieces, and fixtures, this is often the case. LEGO DUPLO element designers will make sure a piece can fit with other pieces in at least one primary way, but there are other considerations as well, like scale in relation to other pieces and fitting the figures properly.

We should remember that while LEGO DUPLO is a construction toy, it is meant to be for the youngest of children. So, while building and rebuilding is possible, the parts are not designed to be attached using complex building techniques or repurposed in many different ways, as we see in LEGO System sets.

As far as the idea of integrating the bathtub with the slide, how about putting a couple of LEGO System plates under the pieces to even out the height? LEGO System plates are compatible with LEGO DUPLO if placed on the underside. I do not have the pieces to test this out myself, but OP's question made me curious.
> 3 votes

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Tags: piece-information, duplo
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# Question
Title: Please Help! My LEGO BB-8 Minifig Head Is Stuck In a Helmet!
My younger brother lodged his BB-8 head in a helmet, and I just can’t dislodge it.

# Answer
Show your little brother just how super chill you are by easily solving all his problems.

Just get a normal minifig and pop the head off that. Stick the neck into BB-8 and helmet, and with the extra leverage, you'll be able to *snigg-wiggle* and separate head from helmet.

Watch the non-delicate surgical procedure *here* on *Youtube*. Just skip forward to the 52 second mark of video. Later!
> 4 votes

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Tags: minifigures, star-wars, disassembly
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# Question
Title: How to prevent discoloration or parts in storage?
I recently moved into a 1 bedroom apartment, and I am storing my Lego sets out in the living area. There is one problem: one wall is practically all window. Since it is unrealistic to have the blinds closed all of the time (since the lighting isn't great), and I don't have the space or money to buy display cabinets with the special glass that filters UV light, I installed UV film to the windows.

Will this be enough to save my Lego sets from suffering from discoloration, or should I be doing something else? This situation is only for a year or two, then I hope to buy a house where my sets can safely live in the basement, away from sunlight.

# Answer
Product description says:

> UV protection helps reduce fading on flooring, furniture, portraits, blinds and draperies

Reduce, not eliminate, because such film cannot remove 100% of UV, and regular light can also participate in fading a bit.

If you want to store them, not to display them, then box will do. One that isn't transparent. There are opinions that airtight boxes help, too, but I haven't tested that. Regular dark box did a pretty ok (not perfect) job for me when I stored my bricks for many years.
> 3 votes

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Tags: storage
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title: Black 2x4 curved top piece of assembly

text:
# Question
Title: Black 2x4 curved top piece of assembly
This piece does not have an identification number on it. It appears to be part of a larger assembly. At each side are two 'legs', neither of which have stud receptacles, so it doesn't hook on to studs.

I'm guessing it slides down inside something as a top piece.

Can someone tell me what element it is?

# Answer
Technically you don't ask what that element is, but I'm guessing that's what you want to know.

I think it is: LegoFabuland Container, Side Bags / Saddlebags
> 5 votes

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Tags: piece-information
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title: Identify these window panels ~4x3

text:
# Question
Title: Identify these window panels ~4x3
These window panels came in a bulk buy and don't fit any of the accompanying windows. I would have dismissed them as not LEGO, except the greenness exactly matches other trans green elements. They are approximately 4 studs wide and 3 high, therefore they do not fit inside a frame of that size, and are too small for the next size up.

# Answer
> 3 votes
These glass panels are

Trans-Green Glass for Window 4 x 4 x 3 Roof

from 6940-1 - Alien Moon Stalker

they fit with

4447 - Window 4 x 4 x 3 Roof

4741 - Window 4 x 4 x 6 Outward Sloping

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Tags: piece-information, part-identification
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# Question
Title: What are these numbers for this element name?
I have a part inventory for a set and it has some axles with numbers next to them. This is not a technic set, but I imagine the numbers are the same as in this question - LEGO Technic part Numbers

But one of the axles has two numbers (5,5) - is this a comma because of the locale in which it was purchased uses the comma as the USA would use a (dot) for a decimal? Or does it have something to do with the fact that the collar on the axle isn't at the end?

# Answer
Bricklink lists it as

> Technic, Axle 5.5 with stop

The blue number is the length of the axle. It is mentioned in the part list to distinguish axles of different lengths in a set.

In this case, the length is 5.5, so yes, it is written as `5,5` because of the locale.
> 10 votes

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Tags: instructions, size
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# Question
Title: Mindstorms Chromebook app Stuck in Zoomed-Out Position
We are using the LEGO Mindstorms app on Chromebooks. Our test program got zoomed-out to the point of being too small to read.

The remainder of the screen is normal sized. We've tried using 2 fingers to zoom-in and out, but to no avail. Any suggestions?

# Answer
> 1 votes
**SHORT ANSWER:**

Look in upper right hand corner of your project page and find the icon that looks like this \[**1:1**\] and click it. It will center and reset the zoom of your program.

Isn't two finger zooming an *Apple* touch screen thing, like we do on an iPhone? So, unless you're used to doing this on your Apple tablet at home, the two finger slide technique won't work on the class *Chromebook*.

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**LONGER ANSWER:**

A few disclaimers first, I don't have a Chromebook, or any LEGO Mindstorms sets... (yet), so I can't be totally sure of what you mean or every detail I say. So, with that said, let's dance!

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So, I watched a video of *cool teacher Mr. Hino*, downloading the *Windows* version of this app on his class *Chromebook*.

So, to understand your question further, I downloaded the same *Windows* version app on to my PC, and have installed/launched the program.

Assuming your app is the same as my app, I took some screen shots to point out where the Zoom In/Out stuff is.

1) So, this picture is the Lobby/Row of Robots when we start up the program.

2) We need to get to a "Project". Located in upper left hand corner. Click to pull down the menu.

3) We'll either choose to start a "New Project", or if we have one saved, "Open Project" that already exists.

4) This picture is where you're *zoom-stuck*.

5) Look in the upper right hand corner and you'll see some icons in a row.

6) You'll see magnifying glasses with "-" sign, "+" sign, and "1:1" zoom reset.

7) Click "1:1" Zoom Reset.

8) *FRIGGEN-FIXED*!

**EXTRA CREDIT ANSWER:**

There are keyboard combinations called shortcuts that make life *hella*-easier.

The most common are:

"CTRL + C" = Copy.

"CTRL + X" = Cut.

"CTRL + V" = Paste.

Don't know if your Chromebook has a mouse wheel, but...

"CTRL + Mouse wheel UP" = Zoom IN.

"CTRL + Mouse wheel DOWN" = Zoom OUT.

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Tags: mindstorms, software, labview
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# Question
Title: What is this 2x2 white brick in the shape of a figure driving a go kart?
I have a 2x4 white Lego brick in the shape of a figure driving a go kart. It has a stalk to accommodate a head with Lego embossed on it. There is no serial number except for a 4 stamped underneath. Does anyone know what this brick is and what set it's from?

# Answer
> 6 votes
Based on your description, i think you have

x351 - Brick, Modified 2 x 2 Racer Driver No Head

This comes from:

4593-1: Zero Hurricane and Red Blizzard

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Tags: minifigure-identification
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# Question
Title: Program for NXT golf robot not looping properly
This is what I made:

* I will put this robot straight in line with the ball
* I have to make this robot go forward and once it reaches the ball, I have to make it stop and hit the ball with the swing shown in the picture
* I used ultrasonic sensor to determine if it reached the ball

It has to identify if it's a red ball or blue ball with the light sensor. If it's a red ball the robot should hit the ball and if it's a blue ball it shouldn't hit the ball.

I used while and if statements but it doesn't seem to work properly. If I use break; then it stops the program instantly when I start it, so I didn’t use break, but if I start my code, it goes forward and stops and then continue this It just wouldn't go continuously

Here’s the code I wrote:

```
#include "NXCDefs.h"
task main() {
  SetSensorLowspeed(S2);
  ClearSensor(S2);
  SetSensorType(S1,SENSOR_TYPE_LIGHT_ACTIVE);
  SetSensorMode(S1,SENSOR_MODE_PERCENT);
  ClearSensor(S1);

  while(true) {
    OnFwd(OUT_AB,75);
    if(SensorUS(S2)<=16) {
      OnFwd(OUT_AB,0);
      if(Sensor(S1)>49) {
        OnFwd(OUT_C,-70);
        Wait(2000);
      }
      else {
        Wait(500);
      }
    }
  }
}

```

# Answer
> 3 votes
Looking at your code, there are a few things that you need to consider.

Firstly, you have a `while (true)` loop which will run infinitely. The first thing you have after the loop is `OnFwd(...)` which will turn motors A and B on.

Together, this means that whatever you do next, when then you will run the code again, turning on motors A and B.

The next thing to be aware of is that `Wait(2000)` is milliseconds. 2000 milliseconds is 2 seconds, so you will only turn motors A and B off - stopping the robot - for either half a second, or 2 seconds before the loop starts again, and the robot starts moving again.

In the case where both `if` statements are true (presumably when it detects a red ball - but I haven't double checked either the Sensor or SensorUS commands), the robot will stop, the motor C will start, then 2 seconds later the robot will start again.

I would suggest increasing the values in the Wait statements (you could use time constants such as SEC\_5), and adding a `break;` after the Wait(2000);

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Tags: mindstorms, nxt, programming, nxc
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title: What is this EV3 controlling app

text:
# Question
Title: What is this EV3 controlling app
What is this EV3 controling app that is used here:

https://youtu.be/Sjix76QjtMU?t=1m43s

# Answer
> 5 votes
The link in the video is broken but I could find it on the Google Play store.

It looks like it is called Mindstorms Custom Controller.

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Tags: ev3
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# Question
Title: How to place minifigure legs into normal LDD bricks, like a 1x2 brick?
Let me clear up the confusion surrounding this question to the best of my abilities

I'm currently in the final steps of finishing of a mech project I started some time back, finishing now at the hands, literally, of the mech. I have decided to use minifigure pants/legs (the bottom section of the minifigure) as the figure aspect of the mech. This mech is in LDD.

What I want to do is place this brick

into this brick in LDD

How can I go about doing this in LDD?

# Answer
> 7 votes
I see what you mean... Friggin' annoying! Can't do it Stud.io Ver 1.0 (157) either. I haven't installed Stud.io 2.0 yet, to see if it's possible in the upgrade.

Hmm... You could... Just create a work-a-round that could potentially make your model a little more unique.

These program issues are frustrating, but they're fun when they force us to think of an alternative.

Here, try these *Mech Fisticuff Gauntlets*. The pictures look like nonsense, so let me explain the layout.

**FRONT VIEW.**

It reads loosely in columns from left to right. Your new fist configuration build are the 4th and 5th Columns.

* 1st Column: Dark Gray 1x2 brick = Height 3 Plates.
* 2nd Column: Blue MiniFig Legs = Height 5 plates.
* 3rd Column: The total height of Legs and 1x2 brick. = 8 plates high. LDD won't let us stack a 1x2 brick on to leg stalk.
* 4th Column: Our alternate fist, fingers fully extended. (Note: It will be an unnoticeable 1/2 plate shorter then your original fists.
* 5th Column: Our alternate fist, fingers curled up, forming a Left fist.
* 6th loose splatter pieces: Four individual pieces to our fist recipe.

1. 93062 Skeleton Leg.
    2. 26047 Modified 1 x 1 Rounded with Handle.
    3. 99780 1 x 2 - 1 x 2 Inverted.
    4. 15573 Modified 1 x 2 with 1 Stud with Groove and Bottom Stud Holder (Jumper).
* 7th Pointing Hand of Prime.

**Final Note**: *LEGO* may not have those Skeleton legs in the colors we want in real life, but look through for other minifig leg or hinge+1x1 plate combination to get your Mech finger/knuckles right.

**EDIT**=\>***HERE*** For reals. You can download my LDD file from my Google Drive, and import the alternate into your build file in LDD. Save you some time.

**BACK VIEW.**

**SICK VIEW.**

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Tags: building, minifigures, ldd
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