title: Which LEGO boxes are compatible?

text:
# Question
Title: Which LEGO boxes are compatible?
TLG has produced a number of sets which come in reusable plastic boxes. I'm curious to know which of these are able to be easily stored together. Primarily, I'm wondering which boxes can be stacked, but if there are any that are compatible in other ways, that would be interesting, too.

As an example, these two boxes can be stacked on top of one another:

There are other variations, even in production currently, which aren't compatible with this style. For example:

I'd like to know which boxes are compatible with others.

# Answer
There has been a staggering amount of different size and shape LEGO buckets, tubs and boxes. A lot of them are stackable with each other (meaning the same size and shape box produced at the same time can be stacked). I think narowing down the question would be helpful. Are you looking for LEGO boxes currently in production? Or all boxes LEGO ever produced? I just did a quick search on Bricklink and over 300 results came up just for LEGO buckets (similar to the ones you are picturing above): http://www.bricklink.com/catalogList.asp?pg=1&q=bucket&catLike=W It would be huge work to try to work out the compatibility of all of them.
> 3 votes

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Tags: storage
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title: NXT motors not moving?

text:
# Question
Title: NXT motors not moving?
I've been looking around the net for a solution to this problem, to no avail.

After taking my NXT v1 out of storage, I tried using a motor, but it sortof just, moves back and forth once, then 'brakes' and resists any movement. I did forget to take the batteries out when I stored it, and it was stored for about 4 months. I don't think its the motor, as all three, in all three ports and in different combinations do the same thing. Everything else is as normal on the NXT, even the rotation sensor measurements. Its only applying power to the motors that causes problems.

Just as a side note, if I try to add motors, it interferes with my program. One example is when I make a program with a Forward 5 block on the NXT, it stays on that block forever, with or without the motor connected. Another example is in a NXT-G program, it does the same thing, sticks on the motor command.

I will call tech support as a last option, I'm just wondering if anyone has any idea what could be wrong, and any way to fix it. Thanks.

# Answer
> 7 votes
To work properly, the Forward 5 block on the NXT as well as the Move block of NXT-G require that TWO motors be connected on ports B and C. That's probably the problem you see... To test a single motor, there is the motor block.

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Tags: nxt, mindstorms, motor, repair
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# Question
Title: Is it possible to build Lego bricks with a makerbot replicator 3D print?
Is it possible for plates, tiles or small pieces ? Is it possible to use MLCAD with a Makerbot replicator?

# Answer
> 13 votes
(fair warning: I work for a 3D printer company \[Type A Machines\])

I thought this cross-posting up on the RepRap forum would be useful here.

**Summarizing that post:**

It *is* possible to 3D print LEGO-compatible parts on desktop 3D printers, but with caveats:

1. The fit will likely never be as tight as real LEGOs. Those are *tough* tolerances to match. LEGO Corp are (I've heard) the masters of injection molded plastic.
2. The fit we achieved is not bad though, but to make it work you can't just print the holes at the exact diameter and just hope it works.
3. I did my models in CAD software and (CRUCIAL POINT) had to expand hole sizes by about 1/2mm to get the right fit.
4. I added 1mm chamfers to the holes as well.
5. I also widened the holes after printing with a 4.8mm drill bit. No power tools needed, just a few turns manually.

...but with those caveats, it's totally doable. The holes I printed stuck quite nicely to the top of a standard LEGO 8x8 plate. Of course, it's crazy to try and print any standard LEGO/Technic brick. LEGO corp does that so much better than you ever will. The interesting thing is making custom pieces that you'll never see from LEGO. There are a *lot* of interesting 3D designs out there that - with the methods above - allow you to turn them into a LEGO component.

# Answer
> 8 votes
LDview can directly export LDraw files to .STL. But the problem is that the mesh obtained may not be suitable for 3D printing, many of LDraw parts are not "watertight", or contain surfaces inside the part volume (eg. studs are simply lain on flat top surface).

# Answer
> 4 votes
You can't directly export from MLCad to the .STL format that the Makerbots require, but there are workflows you could probably set up.

MLCad doesn't really have many export options, so you're better off using something like LeoCAD which can read .ldr files from MLCad, and export as other formats.

1. Using LeoCAD, add the part you want to print to the scene.
2. Export as either .3ds or Lightwave .obj, and import into Blender.
3. Export from Blender as an .stl file (native exporter).
4. Open the .STL in ReplicatorG and away you go.

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Tags: software, manufacturing, cad, 3d-printing
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# Question
Title: How can I get replacement stickers for a new lego set?
I recently bought a Lego Fire Boat (set number 60005) but for some reason, when I opened the box and shook out the contents (as I normally do) no sticker sheet fell out. I was wondering if you could help me out here, as this set is the jewel of my crown. I need them to create a (rather unusual) fire rescue MOC and film but I cannot do this without the stickers. If you can help me here, it'd be much appreciated. Thanks guys!

Ciaran

P.S. can you give me somesolutions?

# Answer
> 4 votes
LEGO Customer Service will be probably be happy to help you out. They've been happy to replace missing or broken parts for me in the past. They have an online service for requesting replacement parts here:

https://wwwsecure.lego.com/en-us/service/replacementparts

I don't think sticker sheets are listed in the inventories on that page though, so you'll have to add it manually using the "I can't find what I'm looking for" link at the bottom. Once the sheet is added to your cart, you just need to checkout and provide an address for shipping purposes.

If you have any problems, you can also contact customer service directly from this page:

https://wwwsecure.lego.com/service/contactus/

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Tags: stickers, moc
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# Question
Title: How should I connect two LEGO cylinders with pistons to measure the movement caused by sea waves?
As part of a school project I need to make a model of a snake electricity generator. I would like to build this with LEGO elements, and for that, I need to measure the movements of the cylinders relative to each other by mean of the piston connecting them.

I have an extensive LEGO collection, but I have difficulties imagining the best configuration so that the piston has the maximum moving range. In addition, the system needs to be floating, as the movement of the cylinders is caused by waves at the surface of the water.

# Answer
It's difficult to suggest parts without knowing what sets are in your collection. Here are some thoughts to help with assembling this project.

1. Notice that the snake consists of the following pattern:
`float tube -> pump section -> float tube`
The float tubes are the elements that keep the heavier pump sections afloat. You'll need something similar to recreate this with Legos. You could put balloons inside of the float sections instead of making the Lego portion watertight.
2. The float tube / pump section pattern is connected at right angles for each subsequent section. This is the key in allowing the snake to flex in three dimensions (X, Y, Z). There are a number of parts that you could use attached to the outside of cylinders to create this connection.
3. The arms driving the pistons are encased in a flex conduit that is larger than the arm itself. It's hard to see in that diagram, but the arm driving the pump never bends. Said another way, the arm only moves in one dimension - back and forth. I don't know of any Lego parts that would allow for this configuration. A technics rod plus a flex conduit would look pretty close to what you need. But the Lego pieces with holes are generally sized to allow the rod with a pretty close fit. And you need something with a sloppy fit in this case.
4. Measuring the motion is going to be challenging. My first attempt would be to put a spring loaded slider against the piston along with a ruler next to the slider. You could then measure the motion assuming you find a solution to the fit issue from #3 above. If you wanted to convert that motion to an electrical measurement, you'll need some sort of transducer. A mindstorms motor *might* do the job, but I have no idea about how to program and monitor for that type of a thing.
5. Finally, decide upon what aspect you want to measure to indicate the motion. The edges of the tubes are actually moving in two planes of motion. As the edge moves away from the piston, it rises up a little bit to accommodate the pivot point.
> 2 votes

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Tags: building, technic, pneumatic
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# Question
Title: Power Functions battery box and receiver limits
What combination of motor/Receiver/battery boxes are possible/supported?

example: 2x XL motors, 1x M Motor, 1 light using 1 receiver and 1 battery box.

# Answer
> 9 votes
The present line of battery boxes all provide 800mA of current and have overload protection to ensure that this level is not exceeded. Here's what the LEGO website has to say about powering motors:

> As a rule of thumb, you can drive 2 Power Functions XL-Motors, 3 Power Functions Train Motors or 4 Power Functions M-Motors at the same time from one Power Functions Battery Box.

That's the basic high-level view. LEGO provides more details about each motor. You can check these out on the element specs page. Here's a list providing the current consumption for each motor type under "normal conditions":

So, in order to stay within TLG's recommendations, you shouldn't be running anything totalling more than 800mA from the above list off of a single battery box. Also be aware that if you are doing things which require a lot of mechanical power, such as heavy lifting, your motors will draw additional power. A stalled XL motor will overload the battery box by itself, for example.

As far as I know, overloading the battery box doesn't cause any long term problems, so there isn't an issue with testing your configuration to see if the battery box can handle it.

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Tags: power-functions, motor, battery
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# Question
Title: What is the purpose of the hole in the 12 x 12 boat bow (6051)?
I recently received Renegade Runner (6268), and I noticed that it has a somewhat awkward hole in the bow:

The main bow piece has a hole for some reason, but I'm not sure what it is for. Here's the part:

As far as I could tell, this is a list of all sets which use this part:

In each of these sets, the hole in the front is simply left open. Is there some reason for this?

# Answer
I didn't intend to answer my own question, but after reading through the comments and doing some more digging, I think it is clear that this was intended to be a hawsehole (hole that the anchor rope passes through).

The 12 x 12 boat bow in question is a chronological descendant of the 16 x 12 boat bow:

That larger part was created with the launch of the Pirates theme in 1989 and was used in the two flagships of that time: Caribbean Clipper (6274) and Black Seas Barracuda (6285). Carribean Clipper clearly uses that hole for the anchor rope:

The 12 x 12 bow didn't appear in a set until 1992, so my best guess is that this hole was included to match the earlier part, but set designers ended up not actually using it for that purpose.
> 7 votes

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Tags: piece-information
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# Question
Title: How many standard 2x4 LEGO elements are produced in a single 2x4 mold injection?
Just how many standard 2x4 LEGO elements are produced from a single mold injection? I realize the molds are used over and over again, but how many bricks does a 2x4 element mold produce at a time?

# Answer
> 5 votes
I seem to remember it's 2 rows of 8 bricks, with the plastic flow coming in the middle and being distributed in the mould through a pipe running between the two rows, but I can't find any reference for this.

It could very well be that future moulds are optimised to hold more, though, but that's porbably not going to happen unless there's a good reason. Another example I heard is that when they started producing 5L Technic axles, the new mould contained twice as many axles as the one used for 4L axles - with a net result that the 5L axle costs less to produce than the 4L one, which is reflected in set design. You would think they would also replace the 4L axle mould, but considering the price tag of a such a mould, it's not interesting to do so until the mould is at the end of its life (and even then, it may not be worth it to design a new one rather than to just reuse the previous design).

Edit:

Well, I was wrong on it being 2x8, apparently it's 2x12 (or rather 2x2x6):

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Tags: piece-information
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# Question
Title: What is currently in the LEGO Store Pick A Brick Wall?
The LEGO Stores feature the Pick A Brick Wall, where you can buy a small or large cup of LEGO bricks. The selection changes every now and then.

Where can I find the current bricks that are available at the LEGO Store?

# Answer
> 19 votes
The bricks in the Pick A Brick Wall are subject to change. As soon as the supply of one type of brick is exhausted in a store, they replace it with another type of brick. There is no particular rotation or order, it is just whatever happens to be in the delivery that the store gets from Lego.

From Lego.com:

> Selection varies by store and the elements are always changing

The brickbuildr.com website has a section dedicated to an effort to inventory each Pick A Brick Wall through submissions from the community (not the Lego store itself), but it is often a little out of date.

# Answer
> 3 votes
I wrote a website where users can update the contents of the Pick A Brick wall for various Lego stores. The site is http://www.wallofbricks.com/

I used my iPhone to inventory the wall at the Lego store in Orlando, FL. If you inventory your local store please send me some feedback on how the process works. I tried to make the GUI easy to use from a cell phone so that you can inventory a wall quickly.

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Tags: pick-a-brick, lego-store
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title: Damage Boiling LEGO Bricks

text:
# Question
Title: Damage Boiling LEGO Bricks
I bought some LEGO bricks from shop on Bricklink and received them yesterday. In order to make sure that the pieces were nice and clean (they were used) so that my two year old can play with them, I boiled them for a minute first. I've done this several times before and never had any problems, however this time, I think I had some pieces warp significantly and I think one was discolored (black piece that turned half white). They warped so bad that I had to throw some of them some away.

I've seen people on this forum talk about boiling LEGO bricks before and I've personally done it before without problems. Was this just a fluke or did I boil too long (maybe 2 min max)?

# Answer
The boiling temperature of water is 212 Fahrenheit (100 Celsius). The melting point of ABS plastic (the material LEGO is made of) is 176 Fahrenheit (80 Celsius). Therefore LEGO should NEVER be put in water that reaches boiling point or anywhere close to it.

If you want to clean your LEGO, the best way is to just put it in a tub with luke-warm water and a mild soap. Let is soak overnight, then rinse it off with clean water. Here are some further references you can use:

http://thebrickblogger.com/2010/12/cleaning-dirty-lego/ and http://thebrickblogger.com/2010/12/cleaning-dusty-lego/
> 16 votes

# Answer
I can also suggest putting them in a solution of vinegar mixed with water. Its excellent at killing germs and cleaning the legos. See more on vinegar in cleaning here: http://www.versatilevinegar.org/usesandtips.html
> 5 votes

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Tags: cleaning
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# Question
Title: Can anyone help me identify the motor/mechanism used in this?
I've been trying to recreate the Useless Machine found here: http://www.youtube.com/watch?v=QdKtgfmfA7s&feature=c4-overview&playnext=1&list=TLp4R5S7LPESk

In the description, there's a link to a brickshelf gallery that has detailed pictures of the insides of the machine: http://www.brickshelf.com/cgi-bin/gallery.cgi?f=416984

I think I've figured out most of the mechanism, but can't for the life of me figure out what motor is being used, and how the motor stops running once the arm is sufficiently retracted. There doesn't seem to be another switch hiding at the bottom... Those two things have just been bugging me for a while.

First post here, I'm only just getting into LEGO, thanks for the help!

# Answer
> 2 votes
The motor appears to be a very standard 9V motor, presumably using a conversion cable as the switch is a PF one.

As for how it stops, it's not that complicated: when activated,the mechanism pushes the switch back to its "off" position, which is what makes the motor stop. You'll probably think the motor direction is reversed and that's what makes the arm go back in the box, but that's not the case: the motor is actually off and what makes the arm go back is simply its own weight.

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Tags: power-functions
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title: Remote Control option NXT Mindstorms

text:
# Question
Title: Remote Control option NXT Mindstorms
I bought the NXT Mindstorms education software v2.1 along with a Mindstorms kit (which I don't know the version of).

I am trying to remote control a robot I made using bluetooth between my mac and brick. So far, I have connected both devices with bluetooth successfully. I have watched a couple of videos of people remote controlling their Mindstorms bricks and they show the whole process of them connecting the devices and everything (which I have already done), but the last step of remote control process is selecting the option of "remote control" in the top left corner in the "tools" tab in the menu bar.

I do not have that option in the menu. Instead, when I open up the tools tab, a drop down menu opens giving only the options of Calibrate sensors, Update NXT firmware, Block import and export wizard. There was no "remote control" option and I am trying find out where that option is so I can finally start working on controlling my robot.

I am not sure if it is because I need to have the 2.0 software instead of the 2.1 software. If this is the case, I just want to confirm this before I buy something that I might not need.

# Answer
We had the same problem. The current version of the Kit ships with version 2.1 of the software which does not have the "remote control" item on the Tools menu.

We uninstalled this version, downloaded version 2.0 from the below link... and bam... the "remote control" option is there and it even works great through our laptop's Bluetooth connection.

Where can I download the LEGO Mindstorms NXT 2.0 IDE?
> 4 votes

# Answer
All of the commands for controlling the robot are documented on Lego's website here: http://mindstorms.lego.com/en-us/support/files/default.aspx You can write your own custom remote control software in most programming languages, but this is generally difficult on a Mac. Windows and Linux computers are easier to program for, Windows being the easiest. This tutorial ( http://www.extremenxt.com/vbfront.htm ) will get you started programming your own remote controller for Windows using Visual Basic. For a Mac, I would recommend using Python to write your programs. No tutorials exist for doing this in Python to my knowledge, but I can give you code samples if you are interested.
> 3 votes

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Tags: nxt, mindstorms, software, education
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# Question
Title: What part(s) can I use to connect technic liftarms at a 90 degree angle?
Is there a way to connect the two beams in this angle and still keep the connection strong and keep the rotation the same?

# Answer
You probably could use this, which looks exactly like it's the missing part of your puzzle:

You'll be interested to know that this part has intitially been proposed by the first four fans (MUPs, for LEGO Mindstorms Users Panel) working on the very first NXT kit and regularly ran into the same problem as yours. A lot of Technic fans now name the part after Steve Hassenplug, as Brian Davis started called it "hassenpin", eventhough according to him it was more a collaborative effort. It's nice to see that LEGO does listen to the people it invites to workshops (the big wheels in the Emerald Night are another example of this).
> 16 votes

# Answer
If you don't have any of the 90-degree pin connectors, here is another solution using more common parts. It does add to the profile, but is sturdy.
> 7 votes

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Tags: building, technic
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# Question
Title: Are there SNOT models with instructions for beginners?
I would like to introduce SNOT building to my daughter. I have used this method only a few times myself and when I did, I was just messing around. I feel it would be simpler and less frustrating for my daughter if we had models and instructions similar to what a regular set would give you. When teaching children and even for a beginner like myself, it would be great to have step by step tutorials including pictures and an end goal to build confidence using the SNOT method.

I saw that there is a website for learning SNOT techniques but it mainly shows how to put different types of bricks together. Does anyone know of SNOT models with instructions suitable for beginners?

# Answer
> 10 votes
Chris McVeigh has some nice LEGO projects on his website that use SNOT techniques. Many of the projects have PDF instruction guides.

I stumbled on his work after seeing his LEGO ornaments a few years back. Now that the Christmas season is beginning, a few of those ornaments would be a fun way to introduce this technique to your daughter!

# Answer
> 1 votes
There are tools to generate 3D LDraw models which will use SNOT techniques to make sure the overall structure looks nice, most notable:

Depending on her age, your daughter should be able to build the small yellow bunny on that last page, and the result is a very good illustration of why SNOT is useful.

Bram's Flicker page also shows quite a lot of possible SNOT techniques holds a lot of good inspiration as well.

# Answer
> 1 votes
While it doesn't have every SNOT technique, and they call it "sideways building", the official LEGO Master Builder Academy series is really quite good and introduces quite a few very good advanced techniques. I felt they were more than worth the money for my nephews.

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Tags: snot
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# Question
Title: Alternative builds with Star Wars LEGO sets
I currently own these LEGO Star Wars sets:

```
LEGO Star Wars X-Wing Starfighter 9493
LEGO Star Wars Millennium Falcon 7965
LEGO Star Wars Tie Fighter 9492
LEGO Star Wars Emperor Palpatine's Shuttle (8096)
LEGO Star Wars Slave 1 (8097)
LEGO Star Wars Anakin's & Sebulba's Podracers 7962
LEGO Star Wars AT-RT 75002
LEGO Star Wars 9496 Desert Skiff
LEGO Star Wars 9498 Saesee Tiin's Jedi Starfighter
LEGO Star Wars Rancor Pit 75005
LEGO Star Wars Luke's Landspeeder (8092)
LEGO Star Wars 9516 Jabba's Palace
LEGO Star Wars 9515 The Malevolence
Lego Star Wars Geonosian Starfighter 7959

```

I would like to know if there are alternative builds/sets I can make with some or all of them?

My goal is to build something else with what I have that is Star Wars related.

Thanks

# Answer
There is a website, http://rebrickable.com/, that lets you enter the sets you have, and it compares the inventories to other sets to determine which other official sets you can build with those pieces. It also includes unofficial MOCs that other builders have submitted, and it will substitute other part colors if you choose.

For example, just entering the first six sets on your list, it suggested a mid-sized (360 piece) TIE Interceptor MOC (http://rebrickable.com/mocs/anincompoop25/tie-interceptor) for which you already have all of the pieces.
> 20 votes

# Answer
However, if you're looking for an official alternate/combiner build, then no. Star Wars isn't very big on combiner or alternate models, although the early, 1999 sets include inspirational photos. Over the years, Star Wars combiners/alternates have been released via LEGO Club or LEGO Build Together, but unfortunately none of your sets have an alternative/combiner build.
> 3 votes

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Tags: building, star-wars
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# Question
Title: Where can I buy older sets, such as the 10187 VW Beetle?
A few years ago LEGO issued a wonderful set of a classic 1960 Volkswagen Beetle, for an selling price of $120.

A few years have past and I can't find it anywhere except on eBay where it is sold for $400 and above because of its uniqueness and rarity.

Does LEGO still sell older models anywhere in the world? If not, where can I find them?

# Answer
Assaf, please note that this is not part of LEGO's website. StackExchange doesn't sell LEGO sets. In regards to your question, you are right; the #10187 LEGO Volkswagen Beetle is no longer available directly from LEGO. It was a set that was released back in 2008.

LEGO usually keeps sets on the market for a couple of years, sometimes a bit longer if they are very popular. The VW Bettle has been retired quite a while ago, and as you have seen, it is only available on the secondary market.

Besides checking on eBay as you have already done, you can also check on Bricklink. Prices are high, but occassionally someone may sell one for less if the set is used, missing the box, etc. Here is the link to the current listings: #10187 Volkswagen Bettle

LEGO usually doesn't re-release a set, but sometimes may come up with a model similar to the earlier release with improvements. I don't know if this interests you, but currently LEGO sells the VW Camper, which is an absolutely deligthful set. See here: #10220 Volkswagen T-1 Camper Van
> 2 votes

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Tags: shopping, vehicle
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title: What is this yellow hinge piece named?

text:
# Question
Title: What is this yellow hinge piece named?
Recently, I've been flipping through a scan of the March 1995 edition of the LEGO Mania Magazine. Something in the corner of page 11 caught my eye:

This is the 5th step of the "Flip & Build" segment. I am absolutely puzzled; what is that yellow element that forms that arm? (And by extension, how does it clip to that 1x2 black plate?)

Bear in mind that this is from 1995, so it's no surprise if this piece is discontinued now despite being common back then. Really, what piece is that?

# Answer
> 19 votes
I think this is the yellow element: **Hinge Bar 2 with 3 Fingers and Top Stud**

And this the black "plate": **Hinge Plate 1 x 2 with 2 Fingers and Solid Studs**

Both elements are hinges, so they can connect.

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Tags: part-identification
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title: Replacement stickers

text:
# Question
Title: Replacement stickers
Can I purchase a sheet of stickers for 4643 Power Boat Transporter? My son got the item as a gift and a friend of his put the stickers on wrong and he is very upset about it.

# Answer
Since the set is still being produced, you can call Lego Customer Service at 1-800-835-4386, and they will most likely be able to help you.

Failing that, the BrickLink website is a popular place to buy replacement parts. Here's the link for the sticker sheet: http://www.bricklink.com/search.asp?itemID=102237

It looks like there are a handful of sellers in the US selling the stickers for $1-$2. Registration on the site is easy, and most of the sellers accept PayPal.
> 2 votes

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Tags: stickers
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title: NXT brick erratic programming behavior

text:
# Question
Title: NXT brick erratic programming behavior
I think I have a defective NXT brick. It has been programmed to move in a direction for 1 second, wait 1 second and then move in the reverse direction for 1 second. The code downloads on another brick and works fine. I have tried changing the battery pack, changing the motor, changing laptops, changing usb cords, cables, etc. and bricks. The problem has been isolated to the brick. I tried a soft reset and ultimately a hard reset with new firmware download and nothing works. I am truly perplexed. I am using Windows 7 and also tried it on XP. The motor will run in one direction. It starts off slow, speeds up, pauses, and then goes faster. When I turn the brick on, the motor runs briefly before the NXT chirp sound comes up. Yes it is plugged into the correct motor port.

# Answer
> 2 votes
Looks like it might be a defective motor driver chip (though they are pretty tough!). What happens if you connect the motor on another port of the same brick? (with program change to reflect port modification)

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Tags: nxt, mindstorms, programming
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# Question
Title: Why do basic brick boxes tend not to include many gray bricks?
Here are some examples of current basic brick boxes:

Of those, only 5749 has a significant number of gray bricks, and it still includes much less gray than black, blue, green, red, yellow, or white. Here's what the contents of 6177 look like:

In my collection, the grays are much more common than lime and orange, so why aren't grays well represented in these sets?

# Answer
> 3 votes
## Psychology

This eHow article explains quite well why people (children in particular) are attracted to bright colours. Whilst it doesn't directly relate to LEGO, or toys in general, it does make quite a few good points about the effect colours have on our choices:

> "According to a 2005 research article published by the BBC, children can see and even appreciate colors as early as four months old. At that age, however, their eyes may not yet be sufficiently developed to recognize various shades of color or differentiate dull colors like grey and brown."

This doesn't really apply to the sets you've shown which are marketed towards children aged four and over, *although* it may apply to Duplo sets which are made for younger children.

> "a preference for bright colors may be a result of evolutionary developments. Many naturally occurring foods---like tomatoes, apples, oranges, bananas and berries---are bright, bold colors when they are ripe and ready for consumption. By contrast, almost all fruits turn a brown, black or gray color as they pass their readiness for consumption and begin to rot."

Here we have another reference to an ingrained biological behaviour, It's probably insignificant considering how the majority of the bricks and the packaging are brightly coloured.

> "adults typically associate bright colors with fun, happy times. For this reason, many parents bombard children with brightly colored gifts, paint children's rooms bright colors, and deliver marketing and entertainment messages to children through the use of brightly colored cartoons."

I can't claim to know a thing about psychology but from my experience building models as a child, I know that the focus has always been on building something you can play with. A few gray pieces here and there wouldn't stop me from building a car with psychedelic mixture of colours

## Building

Supposing you're a child and you ready to build something from the real world that's both gray and exciting. Well, there are a few animals like elephants, rhinos and wolves you could build but other then that there aren't that many realistic things you could build apart from castle walls, boulders etc... (You are welcome to challenge me on that point)

## Manufacturing

Keeping the amount of colours to a minimum, makes the manufacturing process cheaper. Fewer part bins need to be sourced and delivered to the packaging area (although a large part of this process is automated).

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Tags: sets
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# Question
Title: How can I find out what parts are in a Lego set?
I am building an inventory of all my LEGO pieces and I am looking for a website that can give the pieces in a set with only the set number. It would be easier if there was information for many LEGO sets with the full inventory. I also will need to have a file of all LEGO parts.

# Answer
> 14 votes
Here are the options that I'm aware of along with some basic pros and cons:

## Rebrickable

Rebrickable provides set inventories for nearly all sets. It includes sets from all time, and is still being updated as new sets come out. Rebrickable also provides all set inventories for offline use via its download page.

## Bricklink Inventory Reference

Bricklink probably provides the most complete and up to date set inventory data. These inventories are also very detailed and include extra parts, sticker sheets, etc. If you are a seller on Bricklink, you can also part out sets into your inventory which could be useful to you at some point.

## Brickset / Lego.com

TLG provides nearly complete inventories for sets online via the replacement parts page. You can use this to get part information from your sets, but the interface is lacking because this isn't really what the page is meant for.

Brickset provides this same part data in a format which is much better for viewing. Simply search for a set and use the "Parts" tab to view contents if they are available.

These resources have a couple of downsides:

1. They only include relatively new sets.
2. Set inventories aren't as complete as Peeron or Bricklink.

## Peeron

This site is great for old sets, but it isn't updated anymore.

# Answer
> 1 votes
Try the bricklink catolog. They also have inventories like Peeron, but a little bit more detailed (like part variations) and also include stuff like extra parts and Ninjago cards.

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Tags: building, piece-information
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# Question
Title: Where are the cloth / fabric minifigure capes / cloaks in my set?
I purchased The Mines of Moria (Lego Lord of the Rings item 9473) directly from The Big Store in Legoland, Florida. When I opened it up at home, the capes / cloaks for Pippin and Boromir were missing. No other parts appear to be missing, and the set did not appear tampered with.

I went to the LEGO website to report the missing items. The only items listed as "out of stock" on the website parts list were the capes and, as to be expected, the Cave Troll. While I can understand the fascination with the Cave Troll (it is a popular, obscure, and easy to rip off item from the set), I wonder if capes / cloaks going missing from sets is a chronic problem, as those being the only other items out of stock may indicate a larger issue.

Has anyone else experienced missing minifigure capes / cloaks, or is this issue unique to me? Or, am I just seeing the "out of stock" message and imagining a problem where none exists?

# Answer
> 7 votes
**I found them.**

The capes were packaged in a small, unmarked, rectangular, white, cardboard box that was taped shut. Apparently, this little box came with the set, but someone else assumed it was filler trash and put it on our recycling queue.

Considering the capes are the only items out of stock besides the Cave Troll, it is possible others may be simply dismissing the box, and discarding it as filler. This could explain why they are out of stock (or, as TheBrickBlogger's answer indicates, they are popular items like the Cave Troll).

After discovering the capes, I've cancelled my replacement order. I provided feedback to LEGO recommending they make the container box more obvious.

# Answer
> 4 votes
I have not heard of this problem before and I'm a member of several LEGO communities. However it is quite possibe that a batch is missing the parts, or even just your one box. I would suggest that instead of trying to get the replacement parts online, just call customer service and get them that way. Perhaps they are holding back on online stock because they want to make sure that real replacement issues get taken care of before someone buys the parts as extras. Those little capes are quite popular. ;)

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Tags: sets, minifigures, manufacturing, accessories, replacement-parts
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title: Common, practical use for this piece

text:
# Question
Title: Common, practical use for this piece
I've been digging to some old inventories and noticed that all Bohrok from the Bionicle theme contains this piece:

I'm pretty sure I have this piece in my collection, probably from a Bohrok. At that time, I think I might have dismissed it as not a LEGO piece and I might have tossed it. Turns out, it is. I'm pretty sure this piece wasn't mentioned in the instructions booklet itself. Within this Bohrok set, what is it used for? And how is it used in other sets? Bricklink lists this as a belt/rubber band holder, but I'm not quite sure how it can be used as such.

# Answer
Fikko, it is not a regular part. It is simply a piece of plastic for holding the rubber bands that came in sets to make sure they are visible enough and won't get lost in the packaging. And you could also use them to store your rubber bands so they won't get lost.

These days LEGO uses a little paper-sleeve for rubber-bands, string, etc., however before 2008 the piece you meantioned was used in sets with rubber bands. There is also a larger version for bigger rubber-bands.

Even though it is not a regular LEGO element I have seen LEGO creations that incorporates the piece in creative ways; usually as a face for a robot or statue because of those holes that look like eyes.
> 4 votes

# Answer
Fikko3107 is correct, it is in fact a LEGO rubber band holder, for storing two different sizes of rubber bands. It's purpose insofar as the Bohrok sets are concerned, I'm afraid I don't know enough about Bionicle to give you an answer. Perhaps the instruction booklet may offer some clues?

As masterX244 stated, it is unofficially known as the 'nnenn' element, so named after Nate 'nnenn' Nielsen, who was a talented and prolific builder who used it as his Flickr avatar and who caused quite a stir among the LEGO community by using cut, painted and modified elements from clone brands as well as official LEGO parts. His build were so good, and so numerous, that despite offending purists and building brilliantly in a range of scales, he very rapidly became known as one of the better builders among the community - unfortunately, he was taken too soon from us all in a car accident and we will never see any new creations from this remarkable man, mentor, husband and father.

Fortunately, for those who never got to know nnenn's inimitable style, his Flickr account lives on and can be viewed here: http://www.flickr.com/photos/nnenn

He was also responsible for creating NoVVember (flickr.com/groups/921332@N22/pool/with/5203643999/), a month dedicated to starfighter builds based on the Vic Viper craft from the Gradius Series arcade shoot-em-up games (en.wikipedia.org/wiki/Vic\_Viper).

LEGO (through the influence of set designer Mark Stafford) paid homage to his contribution to the hobby and the community by including his name on the Vic Viper inspired spacecraft that sits on the back of 7066: Earth Defense HQ (brickset.com/detail/?Set=7066-1).

His nickname is visible on the stickers, shown here: http://farm4.staticflickr.com/3315/5721097224\_d1d5a13818.jpg
> 5 votes

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Tags: piece-information
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# Question
Title: How to build a flywheel crankshaft piston pattern with technic?
I'm not sure of the name of the pattern, feel free to edit title if you have a better name for the pattern commonly used in engines. I was just wondering if anyone has built this specific pattern in technic lego. The piston part is not important, i only need a flywheel that takes a cranckshaft forwards and backwards repeatedly. Does anyone know some common patterns for this, with a large raduis on the flywheel?

# Answer
Here's one simple way to accomplish this using just basic parts:

This isn't quite a pure Technic example, but that construction is almost exactly what was used on the steam cylinders on Emerald Night:

Depending on exactly what you are trying to do, there are also some specialized parts that make building decorative pistons simple. For example, here's the V8 from the 8880 Super Car:

There's also the much earlier piston design on 853:
> 6 votes

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Tags: technic, motor
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title: Minifig with multiple arms?

text:
# Question
Title: Minifig with multiple arms?
Is there a minifig that has multiple arms that all have the ability to hold weapons or tools? My 4 year old is asking for one. I thought maybe Doctor Octopus, but can't tell by the pictures if his octopus arms can hold things.

# Answer
> 19 votes
There are already quite a few multi-armed minifigures. I usually won't count Doctor Octopus as one, though. But I'll count it this time.

The very first minifigure to be able to hold more than 2 tools is Doctor Octopus, from the "Spider-Man" theme from 2004. This was achieved by building a harness that goes on the neck. This version appeared in 4 sets, all in different variants.

It should also be noted he received a 4+ figure version, which is aimed to kids 4 and above. This version is not exactly a "minifigure". His tentacle harness is built into the figure, and is not removable. This one was released in 2 sets.

2012 brings another Doc Ock, based on the Ultimate Spiderman TV show, using a similar trick as the 2003 version. This minifigure only appears in one limited edition set.

The 2019 version includes a simplified harness with droid arms, significantly restricting movement, which was reverted in 2020 to a design closer to the original.

The next multi-armed minifigure is General Grievous from the "Star Wars" theme, hailing from the 2005 "Revenge of the Sith" subtheme. He was made out of a specialized head and torso; however, his legs and arms are common droid parts, with 4 of these arms attached to the special torso. This version appears in 2 sets, though one is more highly sought after due to Grievous having an exclusive cape in that one. Both versions came with his iconic lightsabers, but his arm posability are rather limited; they only move sideways, and their wrists don't hinge.

Grievous gets a re-release in 2010 as part of the Clone Wars subtheme. This was, accuracy wise, a major leap. He was composed completely out of exclusive pieces. Now his arms hinge up and down, but like a lot of other LEGO robots, his wrists still don't turn. Also, his second pair of arms attach to the first pair, giving a rather awkward looking angle and less posability. This version appears in 4 sets: 8095, 9515, 75040 and 75199.

Next, we have Frenzy. Frenzy is a Space Police Minifigure released in 2009. He was a large step forward to the original Grievous. He had a special molded head that goes over his regular, albeit uniquely printed, Minifigure torso. This extra head has a twist: it has room to accommodate a pair of droid arms, giving him 4 arms, although the upper two has little use, since their grip is permanently sideways. Still, it's a step up. Frenzy only appears in one set.

2011 brings about Samukai, the former king of the underworld of the Ninjago theme. Samukai is similar to the other skeleton soldiers, but with a massive head that, like Frenzy, fits over his torso and has room for arms. As an addition though, his upper jaw and lower jaw is separate, so he can open his mouth. His head is designed so it can snugly accommodate a second row of skeleton arms. Samukai's top-heavy stature caused by his head prevents him from getting his own spinner, thus making Samukai only appear in 2, very large Ninjago sets from 2011.

In 2012, Garmadon, Ninjago's antagonist, becomes four-armed through less-than-known means. He is the one I truly consider the "first" four armed minifigure. He had a specialized body extension piece that goes over his torso, which is the same as the one in 2011, and a head that goes on that torso extension. He appears in 2 sets, both following suit as Samukai, in the sense that it appears in 2 very large sets. 2013 has a very similar Garmadon, except for a different helmet and staff. This variant appears in 1 set.

Another Minifigure is four armed in 2013, and once again it is from Ninjago. He is General Kozu, general of the stone army. He also utilizes a torso extension like Garmadon, but a different mold. Like a lot of characters in the 2013 Ninjago wave, he is exclusive to 1 set.

Last, but certainly not least, is another Star Wars minifigure named Pong Krell. He uses a similar torso extension as Garmadon or Kozu, but his alien head was incorporated to the extension. He carries his iconic twin double sided lightsabers, and, like many Star Wars figures, is exclusive to one set.

I know this answer is pretty long, but it's very comprehensive. Please edit it if I miss something, or I wrote something wrongly. Bear in mind that all these minifigures can hold conventional minifigure tools.

# Answer
> 5 votes
In addition to Doctor Octopus, General Grievous could also be an option:

# Answer
> 3 votes
Yes, Doc Ock's arms have clips on the end that grab the same things as minifig hands. Mind you, the clutch power on the bit of the clip that goes into the other piece is often less than stellar. :/

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Tags: minifigures
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# Question
Title: What is the history of the Marvel license between LEGO and Mega Bloks?
I just recently learned that LEGO had the license to do Marvel themed blocks back in 2003. When the Iron Man films came out, Mega Bloks produced several Marvel-themed sets. Now LEGO apparently has the license back (as well as the DC Comics license!).

How did that come about?

# Answer
From 2002-05, LEGO sold Spider-Man themed sets under license from Marvel Entertainment in conjunction with the release of the first two Spider-Man movies. These are commonly known as the Spider-Man 1 and Spider-Man 2 themes. This license was apparently only for Spider-Man and characters in the films and not for other Marvel superheroes.

In October 2004, Marvel and Mega Bloks announced a multi-year license agreement that allowed Mega Bloks to use several Marvel superhero characters and create movie-related products. LEGO did not produce any Spider-Man or Marvel-themed sets between 2006 and late 2011.

In 2009-10, Marvel Entertainment was purchased by The Walt Disney Company, with whom LEGO had a long-standing relationship producing Disney-themed sets. In July 2011 it was announced that LEGO had obtained a license to the Marvel characters as part of an expansion of its license agreement with Disney. At about the same time, LEGO expanded its license deal with DC Comics, a subsidiary of Warner Brothers, to include the full line of DC characters. LEGO had a previous license with DC to produce Batman-themed sets, which were first released in 2006.

With licenses from these two major comic book companies in hand, LEGO created two Super Heroes themes, DC Universe Super Heroes, launched in late 2011, and Marvel Super Heroes, launched in mid 2012. Both themes are currently in production as of August 2014.
> 7 votes

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Tags: theme
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title: What does the acronym MOC stand for?

text:
# Question
Title: What does the acronym MOC stand for?
This is a common acronym used in the Lego community - what does MOC mean?

# Answer
> 37 votes
MOC stands for "My Own Creation".

> MOC
>
> My Own Creation. Any LEGO creation designed and built by a LEGO fan without instructions. Generally pronounced “mock.”\*

Found at this Lego glossary.

Brickipedia's version from their own glossary:

> MOC - My Own Creation, a fan- made LEGO model

\*A side note: There may be some LEGO fans who pronounce "MOC" the way the individual letters are pronounced - effectively saying "Em-Oh-See".

# Answer
> 1 votes
A MOC or a Lego MOC, are the initials of My Own Creation, so, if you have made a creation or a Lego model out of your mind, I mean, with no instructions, you've made a MOC.

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Tags: terminology, moc
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# Question
Title: What are the armless minifigures from the LEGO boardgames called?
I see many of the LEGO boardgames come with mini figures which are armless and have no holes for arms. While I think it is kind of ridiculous to not simply provide a full figure, I understand it's probably primarily for usability purposes.

What are these smaller minifigs called?

# Answer
> 8 votes
When looking at the inventory of one of the LEGO games (as if you were missing a part), you can see these are clearly labelled "MICRO FIGURE"

On Bricklink they are known as 'Microfig', Lego Digital Designer refers to them as 'Micro Figure.

# Answer
> 7 votes
Microfigures. Described by LEGO as "Microfigures...The Minifigures for Minifigures!" As far as useability go, it is true that within the Games theme they are only used as pawns/game pieces. However, in recent years, they've seen larger use. for example, in the 2012 Star Wars set "Palpatine's Arrest", it is used unprinted in pearl gold to represent a statue/trophy. As far as the community go, they've been pretty popular with fans to create micro-sized builds, and perhaps even more so as pilots for micro-sized robots.

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Tags: terminology, microfigure
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title: Has anyone just "built a tower"?

text:
# Question
Title: Has anyone just "built a tower"?
I've heard stories about it, but has anyone simply built a "tower" out of lego pieces and bricks? By a tower I mean lots of bricks on top of each other.

# Answer
> 12 votes
It's actually quite a common thing to build. So much so that TLG has held a number of tower building events at their theme parks and at other locations. Here's a photo of what I believe is the current world record. This was completed in Prague and is 32.5 meters tall.

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Tags: building
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# Question
Title: Are all stickers on a sheet used or do you sometimes have spare? Dino HQ set 5887
I built Dino set 5887 recently, but the sticker sheet contains one extra sticker: one of the 'D' things, the pentagram one. One went on one of the walls, the other two round 'D's went on the chopper. I went through the instruction manuals 17 times to find it but for the life of me, I cannot.

Is it correct that I have one spare sticker on this one?

# Answer
You occasionally get "extra" stickers, especially in the Police sub-theme of City, where the sheets have both "Police" and "Polizei" variations:

Police Plane Sticker Sheet on Peeron
> 3 votes

# Answer
That's definitely an extra. I checked the instructions to confirm this.

I can't comment on how common spare stickers are, as I don't personally apply the stickers in general.
> 2 votes

# Answer
Although I have never seen an extra sticker in another set, you are correct in that this set does have an extra "D" pentagon sticker.
> 1 votes

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Tags: sets, stickers
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# Question
Title: How to make custom LEGO signs, newspapers, etc.
I have several ideas, but I am finding it hard to get started. What I am interested in is making my own decals for signs, newspapers, artwork for the walls and others. So far I haven't had any luck. Is there a site that has LEGO clip art backgrounds, lettering, etc.?

# Answer
Well I don't exactly know what you mean buy a sign like one that he/her can hold or a sign in the ground? Moving onto the newspaper you can get white sticky clay and get two white 6x5 pieces or a size you like and fill in the crack in the middle then put one piece of clay in the Lego persons hand and shape it in a Lego rectangle size Hope this helped
> 0 votes

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Tags: stickers
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title: Identification of arm like beam

text:
# Question
Title: Identification of arm like beam
Any part number information about this technic beam?

# Answer
The parts you are looking for are Technic Rotation Joint Disk with Pin Hole and 3L Liftarm Thick and Technic Rotation Joint Disk with Pin and 3L Liftarm Thick.
> 7 votes

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Tags: technic, part-identification
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title: Can I program EV3 with the NXT-G IDE?

text:
# Question
Title: Can I program EV3 with the NXT-G IDE?
I am helping prepare a team for First Lego League and the new EV3 kit is what will be used. We are currently teaching the kids with NXT 2.0 kits that we have using the NXT-G IDE. It appears that we cannot get the \[free\] EV3 Home Edition software until September 1, 2013, losing important time and requiring some learning curve. Is it possible for us to continue using NXT-G software to program the new EV3 kit when it arrives?

# Answer
No, it appears that you need to use the EV3 software to program the EV3 kit, as per the FAQ on the LEGO site: http://mindstorms.lego.com/en-us/News/ReadMore/Default.aspx?id=476781

The EV3 sensors also won't work with the NXT brick either.

Though, I'd imagine if you're getting an EV3 kit, it should come with the EV3 software.
> 2 votes

# Answer
I think I found the answer from a post back in January (unless things have changed since then). It came from user named bungeshea, who said "it is unlikely that NXT-G will work with EV3 bricks as EV3 bricks run a custom build of Linux, whereas older bricks run a custom firmware". So I assume the answer is NO (unless someone creates an NXT firmware upgrade that can emulate the EV3 API...highly unlikely).
> 0 votes

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Tags: programming, software, nxt-g, ev3
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title: EV3 digital interface with sensors?

text:
# Question
Title: EV3 digital interface with sensors?
The EV3 Brick is noted as having both analog and a higher speed digital I/O with auto ID up to 460.8 Kbit/s (UART), and 4 motor port with encoders.

The NXT Brick has 4 sensor ports both Analog and Digital: 9600 bit/s (IIC), and 3 motor ports with encoders.

I know the EV3 brick can use NXT sensors and motors, but I cannot find info on the difference in the communication protocol. Are the NXT sensors and motors less precise then the EV3 sensors and motors? Will the EV3 Brick support more sophisticated sensors and motors in the future? Thanks, John

# Answer
I can't tell much about sensors since the EV3 Hardware Development Kit has not yet been released, but the existing motors have the same precision specifications and are completely interchangeable between NXT and EV3. And yes, hopefully, with the better bandwidth we can expect more sophisticated sensors! See also http://robotsquare.com/2013/07/16/ev3-nxt-compatibility/
> 2 votes

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Tags: ev3
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title: EV3 as master and NXT2 as slave?

text:
# Question
Title: EV3 as master and NXT2 as slave?
Will it be possible to daisy chain a NXT brick as a slave of a new EV3 brick ?

# Answer
As per This LEGO education FAQ, it is not possible to use the USB cable the same way it's done between multiple EV3 bricks:

> Can I connect my NXT Intelligent Brick to the LEGO MINDSTORMS Education EV3 Intelligent Brick? No. It is not possible to daisy chain with the NXT brick.

However, keep in mind this is valid within the scope of official software; it could be that someone later makes the necessary hacks for it to work in some way.

Also, other communication methods such as bluetooth are available which you can likely use to control the NXT brick from an EV3 one, rpovided you program the NXT brick accordingly. It probably won't be as simple, but definitely doable.
> 4 votes

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Tags: nxt, mindstorms, ev3
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# Question
Title: Buying another kit instead of 8293-1: Motor Set?
I want to get some motors but don't know if it is a better idea to buy `8293-1: Motor Set` or try obtain motors from some other sets. Is there any kit challenging 8293?

# Answer
You have several alternatives, and you can combine several approaches if you've got the cash:

1. You can buy individual Power Functions parts from a LEGO shop or from various other vendors. The advantage is that you'll get the specific parts that you're interested in. The down-side is that it'll probably cost you more than buying a set like 8293.
2. You can buy a bundle from eBay. Several vendors make up their own kits that are similar to 8293 but with a slightly different mix of components.
3. You can buy a set that contains Power Functions. This tends to be fairly cost-effective if you're interested in the parts that the set contains, but with the disadvantage of a larger initial outlay. Of course, you could re-sell anything you don't want if you're prepared to put in some effort. The other advantage of buying a kit is that you'll probably learn some new techniques during construction.

If you go for (3), some of your options are:

* 8110 Mercedes-Benz Unimog U 400
* 9397 Logging Truck
* 9398 4X4 Crawler
* 41999 4x4 Crawler Exclusive Edition

Personally, if had the cash, I'd go for a 41999 (assuming it is still available). It includes a great selection of Power Functions components including remote control and IR receiver, a lot of generally useful parts, several exclusive parts (perfect for eBay?) and... well, it's just *very* cool.
> 6 votes

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Tags: technic, shopping, power-functions
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title: Why 2M Cross Axle has Groove?

text:
# Question
Title: Why 2M Cross Axle has Groove?
I was sorting axles noticed only 2M has grooves. Why 2M Cross Axle has grooves? Is it for alignment?

# Answer
> 6 votes
I believe it's mostly so that you have something additional to grip on to when removing it from other elements.

With the 3M+ axles, there is more axle available to hold on to so that you pull off a sleeve or joint nicely, but for some, the 2M is too short.

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Tags: piece-information
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# Question
Title: Where can I find Lego x-pod playoff pods for the game?
I have some of the original pods but cannot find others, where do I get them? I would also need sheets for the things to build and their attacks.

# Answer
> 3 votes
These are no longer in production, so your best bet to find the sets that you are looking for is Bricklink. Here's a list of all the X-Pod sets for sale.

These are the sets that were included in the game:

* 4348 Aero Pod
* 4347 Auto Pod
* 4346 Robo Pod
* 4349 Wild Pod

For building instructions, I'd recommend the instruction scans on Peeron. Take a look at the X-Pod theme there.

Here are the instructions for the game. See this question for more information on those.

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Tags: x-pods
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# Question
Title: How can I remove a rubber band from a pulley?
We have a pulley and a bunch of rubber bands:

We don't know that part numbers, but they all were part of a Mindstorms (RCX 2.0) set. My son was trying use the pulley and band to transfer power to another pulley. But it didn't work out that way:

Now the band doesn't slip off of the pulley. We figure we can cut it off, but we'd kinda like to save the band if at all possible.

Have you ever run across this sort of problem? Do you have any suggestions for removing the rubber band without destroying it?

# Answer
> 8 votes
As I've said before in another answer, I find the #92585 Crowbar is the most versatile and is especially good at removing rubber bands from the #3736 (Technic, Steering Pulley Large) and the #4185 (Technic, Wedge Belt Wheel) elements.

Don't use any sharp/metallic objects like a screwdriver or a pen knife as you may scratch the brick or sever the rubber band.

# Answer
> 7 votes
I was able to successfully get that size band off of that pulley using this brick separator:

I slid the sharp end in between the band and the pulley then worked it under the band and was able to pull the band off without damaging either part. If you don't have a brick separator handy, you can probably use a pointy minifig utensil such as a sword instead. I wouldn't recommend using metal tool such as a screwdriver or knife as this could easily cut the band as you try to remove it.

Good luck!

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Tags: technic, mindstorms, disassembly, rubber-bands
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title: NXT Programming not working

text:
# Question
Title: NXT Programming not working
I recently got back into NXT stuff (keep in mind I have a NXT 1.0). My screen was broken, but I got it fixed. The software works, but I think the programming doesn't. I tried to make the motor move when I push a button. I downloaded it, and then all it did was jiggle the motor. I tried making a text block, but it didn't work - it just said "Run,Done" in a matter of a split second.

Help me! I really want to program stuff on my computer, and not just a 5 move thing on the NXT itself!

# Answer
> 2 votes
From your description, it seems you use a motor block which just tells the motor to start running. This works, but since your program then comes at an end, all motor activities are stopped immediately.

To solve this, you have to make sure your program doesn't terminate immediately. You could either use a wait block, with a fixed timer after which the program (and motors) will stop, or maybe a block to wait for another condition to happen (button pressed, sensor activated, number of rotations reached,...).

Another solution would be to change your motor block and use a "move" block - which instructs a motor to move for a certain time (the block wait for that time to be completed).

Keep in mind this is all from memory though, I may be wrong on the particulars; but in essence I'm confident your problem is due to your program terminating immediately.

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Tags: nxt, mindstorms, programming
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# Question
Title: Can I remotely control the points on PF train tracks?
I'm interested in investing in power functions based trains, but want to automate switching points. Is this possible? What is the cheapest / easiest way of achieving this?

# Answer
There is a pure way of changing the points at a track. It requires as few pieces as you like: a motor and two technic beam/bricks. This video demonstrates the principles of point changing with a NXT motor and will work with PF and RCX.

You can use Mindstorms to program the events that trigger the points to change. It will cost you extra, but there are benefits.
> 11 votes

# Answer
One elegant solution is to use pneumatic elements, as a small pneumatic pump is enough to move the lever. If you're lazy to figure out how, you can buy a kit from a fan which will allow you to control 2 points (you'll need one more pump to generate the pressure). With the included instructions, you can build more controls if you have the parts, or simply buy more kits. (He also sells compatible pneumatic hose by the meter, and his custom waggons are nice as well).

His design is very compact, probably much more than you'll be able to get with electrical power; plus, it saves energy. The only drawback in my opinion is the hoses which you'll need to run from your control station to each point, which are slightly larger that electrical cables.

---

Another typical solution is to use a motor which controls the point. This will take more place, and you have to be careful that the motor doesn't run too far (use a clutch gear). One promising way is to use the new small linear actuator:  which should behave more or less like the mini pneumatic pump; but of course any other Technical solution should be good. Use your imagination, or dive into BrickShelf in search of inspiration.

Of course, you'll need to run electrical wires, or use infrared receivers, but then you'll be limited in the number of points you can control. Note that sometimes, the configuration of your layout means that pairs of switches can be controlled together (think of a bypass to change from one track to the other), so that you can spare some control channels, or wires.

--

Non-LEGO solutions can be achieved with about anything, including solenoids (electrical actuators), which LEGO doesn't produce. One other elegant solution I can think of is to use bike brake cable, but I have no real idea if that would be easy to do.
> 8 votes

# Answer
I just found this link on another forum.

This is a set of instructions for using a medium power functions motor to switch the point. It is quite compact and is compatible with the infrared receiver.

(page 7 of 8) http://www.flickr.com/photos/whoward69/3731639719/in/set-72157621512518259/
> 4 votes

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Tags: trains, power-functions, remote-control
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# Question
Title: Are the Lego looking figures in the picture real?
I stumbled on this picture on the Nerd Fitness blog's paleo diet page:

1. Are they real Lego figures? (both the mammoth and the hunters) or photoshopped?
2. If so, are they correct? Or merely repurposed (e.g. hunters are really from a Viking set, and "mammoth" is just an elephant from some Africa themed set)?

# Answer
Yes, they are real! The minifigures all have standard LEGO body-parts. They are not from any specific theme, but mixed and matched from different minifigures. The headgear and hair-pieces are all real LEGO pieces as well. The beards are from LEGO customizer Brickforge, the spears are from LEGO customizer BrickWarriors, and the capes are standard LEGO. The elephant is also a standard LEGO elephant which appeared in several sets in the past. Here are some reference links:

BrickForge's website: http://www.brickforge.com/store/

BrickWarriors' website: http://www.brickwarriors.com/

Elephant: http://www.bricklink.com/catalogItem.asp?P=elephant1c01

Hope this helps!..(c:
> 5 votes

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Tags: minifigure-identification
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# Question
Title: Where can I find LEGO X-Pod Playoff rules and printoffs?
Where can I find X-Pod Playoff rules? LEGO doesn't seem to be hosting them anymore.

Asked because of this question. Hopefully it can be mirrored on a few sites so that it doesn't disappear again.

# Answer
Here are the PDFs donated by Friend Of George. Here are the unit catalog PDFs.

The starter kit for each pod has an inventory list, a set of cards containing units which can be built, and a set of X-TRA cards. The cards and inventory list can be printed on card stock for better durability.

The Advanced Rules contain additional rules and Advanced X-TRA cards for the game.

The Advanced Strategy Guide contains some tips on how to best choose and use your units, along with movement and placement strategies. It also gives sample sets of units and strategies for each Pod against each of the other Pods.

The boards were generated from the website with no obstacles for maximum flexibility. Bricks should be used for these and placed where desired.
> 8 votes

# Answer
I found here a link to the LEGO website on archive.org with the X-Pod playoff section intact.

The download links for the rules and starter kits still seem to work.

The units catalog is slightly broken, but I was still able to print all of the unit catalogs into PDF format using PDFCreator. For them to print correctly, click on the Advanced Rules tab, then go back to the Units Catalog tab. Click the button for the units catalog you want to print. Select a unit from the list and click Print All Pod Plans.

The arena generator works also.

(Thanks to @JoeWreschnig for finding the cached flash file to give me the correct terms to search for.)
> 7 votes

# Answer
Recently, I found a link to a website that has everything the Lego website had in a PDF format. Here it is: http://korewanetadesu.com/pages/lego/xpod.html
> 1 votes

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Tags: instructions, x-pods, play-off
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# Question
Title: Is it possible to buy Lego Marvel Superheroes mini-figures separately?
I'm a fan of Marvel, and I find it pretty cool that LEGO is making sets and mini figures for Marvel. I personally wouldn't want to buy a whole set of blocks and characters, and I wouldn't want to buy multiple sets to get the characters I need, because I will end up having plural of the same minifigures, and end up spending more money for blocks and parts I don't really want.

All I really want are the following minifigures from the Avengers: Hawkeye, Ironman, Thor, Captain America, Black Widow, Hulk, and even Nick Fury.

# Answer
> 10 votes
LEGO typically does not sell individual minifigures from its licensed themes due to licensing restrictions. Often, another company has an exclusive license to produce action figures from a franchise, which means that LEGO is only allowed to sell building sets. These may contain figures, but there has to be a real buildable component. That's why we see "Battle packs" like this one in the Star Wars theme:

With that said, there is a strong secondary market for minifigs. You can often find the popular characters on eBay, Bricklink, or even Amazon. For the specific minifigs that you are interested in, you may want to check out the superheroes category on Bricklink.

# Answer
> 6 votes
I agree with @jncraton, licensed themes are typically restricted from selling minifigures on their own as that would conflict with action figure licenses. Some amount of construction must be included to make it a building set.

You have some options though. In addition to secondary markets like Bricklink and eBay, several Marvel Super Heroes minifigures have appeared in their own polybags, which is very nearly like just buying the minifig.

For example, Thor: http://www.brickset.com/detail/?set=30163-1

and Hawkeye: http://www.brickset.com/detail/?set=30165-1

On the other hand, TLG has been making a habit of producing some figures as exclusive items in small quantities, and handing them out at places like Comic-Con. If you really wanted one of those figures, be prepared to pay handsomely.

Of course, some figures will only be available in certain sets, so secondary markets are your only option if you don't want that set.

# Answer
> 3 votes
If you buy the set that has the figures you want, then sell what you don't want you end up getting the figures for free. As an example, LEGO 76000 Arctic Batman, RRP £20 but when on sale £13. Say you only want Aqua Man, you could sell Batman, Mr Freeze and the bat boat easily for a fiver each, even after fees you now have Aquaman for free....

# Answer
> 1 votes
LEGO doesn't currently sell the figures on their own, unless as a previous user suggested you buy a poly bag which still isn't the figure on its own. Have you seen a website called firestartoys.com ? you can buy individual minifigure parts such as arms let alone complete figures.

Here's a quick search of the site for super heroes: http://www.firestartoys.com/Shop/LEGO-Minifigures/Super-Heroes-LEGO-Minifigures.html

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Tags: minifigures, lego-store
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# Question
Title: Will using a bright LED to light my MOC harm my LEGO?
I'm building a LEGO model and planning on lighting it with a bank of 5 battery operated LEDs. I know sunlight negatively affects several LEGO colors. Will a bright LED harm the elements in my MOC the same way sunlight would?

# Answer
> 7 votes
Ultra-violet radiation is emitted primarily by sunlight, mercury lamps, black lights.

LEDs emitting visible light will not produce a significant amount of UV radiation required to discolour LEGO bricks. However, LEDs can be manufactured to emit UV light,

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Tags: piece-information, lighting
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# Question
Title: Will learning about EV3 transfer to Lego RCX software/hardware?
If I attend a workshop on EV3 will that knowledge help me get up and running with RCX software and Lego Mindstorm kits we already have at our school? I know EV3 is backwards compatible with NXT but they said nothing about RCX. Guess it's a bit obsolete?

# Answer
> 2 votes
As far as the standard software is concerned, it's probably way too different so that your knowledge of one won't translate easily to the other. If the workshop uses third-party software, though, the gap might be smaller.

As for the construction of a robot and the principles of how to automate it, this should be closer, but there are still noticeable differences, for example using studless beams in newer kits versus studded construction in the RCX.

There is some backward compatibility, mind you, but it's more on the hardware level (meaning with the aid of converter cables you can use RCX motors and sensors with an NXT and that should hold true for EV3 as well).

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Tags: mindstorms
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# Question
Title: Where can I buy big quantity of the same block?
I have a decoration project and for that I need almost 10.000 2x4 blocks (same color or not according what I would find).

Do you know how/where I can buy such a quantity ?

News or 2d hand... I do not mind :)

I got on BrickLink, but I did not find it very easy to use.

# Answer
If you want specific quantities of specific parts your only two real choices are BrickLink or Lego.com's Pick-A-Brick.

Searching for any color of 2x4 brick in quantities of at least 10,000 on Bricklink you can start from the following URL: http://www.bricklink.com/search.asp?pg=1&itemID=264&sz=50&searchSort=P

You'll then need to click the "Show More Filter Options" link and put "10000" into the "Min Qty" field and then click the "Go" button. You'll probably see the same result I did, which is that the only sellers who have that kind of stock are in Europe, which might not be an issue for you, at a minimum price of ~$0.13USD.

Checking Pick-A-Brick (http://shop.lego.com/en-US/Pick-A-Brick-ByTheme) the price per part direct from LEGO for the 2x4 in most colors is currently $0.30USD.

Those really are pretty much the two simplest options. However, for a quantity like that you might want to consider contacting some of the larger BrickLink sellers directly. They can often be very helpful when trying to run down this kind of an order since BL requires that they list their inventory by color, but they may be able to do a quick calculation to determine if they have enough on-hand from the various colors to be able to make a bulk deal and maybe, if you're lucky, maybe even get a deal on it.
> 3 votes

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Tags: sets, shopping
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# Question
Title: Does anyone know why Hagrid has fingers?
Hagrid (hp061 and hp009) both have fingers instead of just the traditional c-cup hands.

Does anyone know why?

# Answer
> 2 votes
Since Hagrid is much larger than others, it is an opportunity to include slightly more detail without looking clumsy. The fingers might increase the illusion of being bigger.

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Tags: minifigures
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# Question
Title: What is piece 4211642 from 10179 - UCE Millenium Falcon?
I'm working on making sure I have all necessary pieces for 10179: Ultimate Collector's Edition Millenium Falcon (a painstaking process, to say the least). I received the set not entirely complete, partially disassembled, and without directions.

I'm using the PDF of the directions to sort and count the pieces, and I can't figure out what this piece (4211642 on the bottom) is supposed to be:

(from center of p.308)

I don't have anything left over that appears to match, and the part number isn't of any help. I've even paged through the instructions to see where these five mystery pieces are used, but can't seem to figure it out. Can't find it on the Peeron parts list.

The PDF is of annoyingly low resolution. Can someone with a printed copy help me out here?

# Answer
According to the LEGO customer service, this part is a "BUSH Ø7.84" (which is of no help whatsoever, as with most LEGO internal names) and has the design ID 6221. Unfortunately, there seems to be no official picture for it yet.

This design ID corresponds indeed to the part which Joel Cohen and BradC have identified; the element id of the same part in black (622126) as found by BradC follows the old convention design id + color id (26 being Black at LEGO). And this part at the LEGO customer service does have a big image which would clear all doubt if we had any left:

LDraw and Peeron know this part as 424 - Technic Handle. BrickLink does too but refers to 6221 as alternate item number. This happens often with parts which have no markings whatsoever and for which the official LEGO design ID wasn't known at the time the part was added to the LDraw library.

Why the inventory at both Peeron and BrickLink misses it is anyone's guess, but it's one of the biggest LEGO sets ever so it's bound to have mistakes. Although I see the list for Peeron has been provided by LEGO itself, so it's a bit weird.

Is the part actually used somewhere? I don't have the strength to read the whole manual.
> 15 votes

# Answer
I think Joel Cohen's comment is correct, it looks like a "Technic handle/hub" (escalating to an answer so I can include pics):

Here's a similar-looking view from the parts list of set 7703 Fire Vulture:

and a portion of the instructions from 7476 Dino Attack that shows how it is used:

So if this is correct, it appears to be a mistake (or misprint). Can someone confirm for me if this piece was included on the parts list of the actual printed manual? Perhaps the PDF was made from an earlier test build?
> 14 votes

# Answer
I'm currently doing an inventory of many of my son's Lego sets, including the 10179 Millenium Falcon set. The search for this 4211642 piece is what led me to this site/thread in the first place :)

I've been searching/sorting through all pieces, but can't find any of these... Me and my son are pretty anal when it comes to *not* losing pieces, and although it's possible we'd have misplaced one or two, I'd say it's pretty much impossible we'd have lost all 5 (The rest of the pieces are actually all there, which is good!!!).

Wanting to double-check, I went through the whole manual to see at which step this 4211642 piece would be needed but, unless I'm totally blind, I haven't seen it anywhere. So at this point I think it's pretty safe to assume this is a misprint in the official manual and its PDF counterpart.

Hope this helps!

Jofu
> 11 votes

# Answer
I'm trying to assemble the 10179 set by buying the individual pieces, since the prices for the set are outrageous. I put the inventory of parts from the PDF version of the manual into an Excel spreadsheet to track piece counts and prices. The total number of pieces comes out to be exactly 5200. If you subtract 5 for the 4211642 pieces that are listed but apparently not included or used, that leaves 5195 pieces, the official piece count for the set. So, my guess is that the 4211642 pieces are not supposed to be in the set.
> 8 votes

# Answer
Well, I have the Falcon and I can confirm that those pieces are not included on this set. That print appears on my manual too, therefore it is a simple print mistake. I have built the Falcon three times (only for enjoying) and those pieces still hide somewhere, on the abbism of the box, so don´t worry. You have all the pieces.
> 4 votes

# Answer
You may want to use the bricklink inventory for the set. But looking through that, I don't see a part with quantity 5 that looks anything like that.
> 1 votes

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Tags: part-identification
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# Question
Title: Does the jumper plate have a Danish nickname?
Does the "jumper plate" (1×2 plate with centered stud) have a Danish nickname like the "Erling"? Who is the designer of this part? And does there exist a catalog of designers of specific bricks?

# Answer
> 3 votes
I cannot find any cases of the Jumper Plate brick having a Danish nickname, the closest you might get to a Danish nicknamed would be a literal translation: jumper plade.

The Erling brick is a very rare case of a brick being named after its creator. I imagine most bricks created nowadays are produced by not one but several people. It's possible that such a catalogue of brick designers exists, but is not publicly available.

# Answer
> 0 votes
Although it is not a nickname, the official internal name of that part is 'Plate 1 x 2 with 1 Knob' according to Brickowl

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Tags: piece-information, terminology
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# Question
Title: Pattern for vertical motion using technic lego
I have a motor and some other components that move a machine vertical on the ground. Inside the machine i need to raise a part by 5 cm, up and down.

Are there some common patterns that can move objects vertically (lift) using technic lego? Torque comes from a motor powering gears.

# Answer
### You can use a mechanism like this:

This is a mechanism that converts circular motion into reciprocating motion. You may need to alter the design for your needs regarding height difference, stability etc.
> 4 votes

# Answer
You can accomplish this using gear racks (3743):

You just have to create some type of channel that allows the rack to slide vertically, and then set up a gear to mesh with the rack. You can do this however you like, but here's a quick example that I built to show you what I mean:
> 6 votes

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Tags: technic, motor
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# Question
Title: What would be a simple trebuchet design at the Minifigure scale?
I would like to have a trebuchet design at the Minifigure scale and simple enough for kids 10+ to build.

Note 1: The counter weight can be any non-LEGO heavy object.

Note 2: On top of the standard LEGO bricks, we have a lot of LEGO Technics and my kids are using them all the time. So, Technics are OK in the design.

# Answer
There are a number of designs on the net that I found with a simple search. Google image search produces images from the merely functional ones like the instructions linked here through to quite realistic looking ones that appear likely to work.

or this big one

The key for a simple, easy to build one is to use wheels on the base. It will shake back and forth when fired which means the structure does not need to be as strong. If you don't do that then the base will need to be similar in size to the arm, as in both pictures above. I am a little surprised that there's so little bracing on the arms of these models, as you can make a much stronger model using a tension member at least on the top of the arm, if not below.

But with Lego the main issue will be the density of the weight. Lego doesn't do high density part, so most people use non-Lego weights. Since you're willing to do that it's easy - the first picture shown has a lead weight, which is why it's hard to see that there's a weight at all.
> 10 votes

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Tags: building, design
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# Question
Title: How to efficiently identify Lego bricks and find their names?
I've found http://rebrickable.com/myparts linked in one of the answers here on this site and I'd like to list all of the parts I have at home (probably a thousand or two). The problem is, there is **a lot** of similar pieces on Rebrickable, including some which have "similar" in the thumbnail image, or have three zeros for *parts*, *sets* and *colors*.

For example there is a 1x2 brick with no hole in it: 3004. What is the difference between this and 3004px3? Can I filter the useless bricks out? How can I find the version with circular hole in the middle used a lot in Technic?

But the whole question boils down to: **How to efficiently identify bricks and their names?**

# Answer
In my experience, the Bricklink catalog is the most complete parts list. It is organized in fairly logical tree by part type (brick, plate, wheels, slope, etc). Once you get familiar with it, you should be able to identify parts fairly quickly.

If you take a look at the 2 parts that you mentioned in your example on Bricklink, you can clearly see the difference between them:

3004:

3004px3:
> 2 votes

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Tags: piece-information
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# Question
Title: EV3 additional build instructions - PDF download or print possible?
The EV3 retail edition comes with printed instructions to build only one of the possible robots and it appears you have to use the software to view the build instructions of the other models.

My question is: is it possible to download or export/print these additional model instructions?

I have attempted to find both downloads (Lego's PDF search function returns nothing) and an export/print option to no avail.

# Answer
> 2 votes
Edit to add:

PDF downloads are now available from the LEGO Site:

> 3D Building Instructions

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The images used for building instructions are available (jpeg images) in folder `C:\Program Files\LEGO Software\LEGO MINDSTORMS EV3 Home Edition\Resources\ContentPacks\Retail\nonlocalized\LEGO\pack0\projects` (more or less, depends on OS and installation choices). **Take care not to modify anything there, as you might need to reinstall the software!**

It's a bit more complex for .ev3 project files containing building instructions (eg. downloadable bonus models):

1. Open the ev3 project file as if it is a zip archive.
2. Inside you'll find a file named ActivityAssets.laz. Open this one as a zip archive too,
3. it contains all the images for building instructions. You can extract those images to a separate location
4. then you can print those images or build a PDFfile, you can put that on your tablet...
5. take care not to modify the project files!

**Remember that these images are the property of their owner (LEGO or model builder), use them for you own personal needs only!**

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Tags: mindstorms, instructions, ev3
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title: Naming a program in EV3 software?

text:
# Question
Title: Naming a program in EV3 software?
I have figured out how name a project but cannot figure out how to rename a program.

# Answer
> 4 votes
Just double click on program's name in the tab.

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Tags: software, ev3
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# Question
Title: Is (C) engraved on a piece an indication that it is Cobi brick?
I know that Lego prints their logo on almost all of their bricks, but some are not given this privilege. I have a couple of pieces, 3x3 in a shape of 2 fingered foot, two pin holes on front corners and one pin hole in the back and an axle in the very middle which goes parallel to the ground surface.

Now it would be all fine for me, but they also have engraved "C" in a circle which can either stand for Copyright or Cobi (a polish toy producer). I have failed to find these pieces on Bricklink but I vaguely recall them to be genuine Lego pieces. Can someone help with identification of them?

# Answer
> 4 votes
The symbol stamped on the parts you are asking about is the international copyright symbol © and is common on nearly anything with a copyright and not indicative of any particular brand or producer. A decent description of the use and purpose of the symbol can be found at http://www.copyrightlaws.com/international/522/

The tops of Cobi bricks have "Cobi" stamped on them. They also have a limited range of non-brick/plate parts available and have not duplicated many of the Technic parts, including the part in your image (at the time that I am writing anyway).

LEGO produces many parts in many different kinds of plastic and so while a part might not have the same feel as a standard 2x4 brick it doesn't mean that it isn't a LEGO part. The Bionicle/Hero Factory series of sets in particular use a lot of parts molded in plastic that is much less stiff than the ABS used for the System bricks. You were very close in your identification of the part in your own answer as "Technic, Axle and Pin Connector 3 x 3 with Axle" (Though the correct BrickLink part number is 111b, not 113b), however the actual part is instead "Technic, Pin Connector 3 x 3 with Axle" since they appear to be sloped on the ends rather than being a standard width for the entire part. The official LEGO name for the part is "32175 FOOT WITH CROSSAXLE" (Found in LDD v4.3, Brick Version 1182).

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Tags: part-identification, 3rd-party
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# Question
Title: How to store large amounts of bigger bricks?
I am aware of this question and of this post blog on Evil Mad Scientist which include a couple of interesting. My issue with the first one is that it is completely unsuitable for larger amounts of bigger bricks (like 2x2, 1x4, 2x4 and so on) and I'd like to avoid stacking presented in the second link.

I thought long and the best idea I had is to get a couple of the Lego Storage bricks in different colors and store particular color in particular box. The problem is, if I had 50 yellow 2x2, 50 yellow 2x3 and 50 yellow 2x4, I'd have hard time finding two 2x8. Not to mention different shapes and sizes of plates, technic bricks with holes and the studless technics.

Perhaps I am asking for impossible, but **are there any solutions for storing large amount of bricks, technic bricks, technic studless bricks and plates in different shapes and colors (I am thinking at least 10 per color & shape and 5 per color & shape of the less popular combinations for the starts) in a way which makes it easy to find the exact piece you want?** I don't mind mixing different shapes or colors as long as the big volume of one type won't make it too difficult to find others in the same container.

# Answer
> 3 votes
It depends a great deal on your play style and just how much Lego you have, and on what other skills and equipment you have. Using official Lego containers is the most expensive and least flexible option, as they are not really in the storage business. The Technic Briefcase is a good start if you have Technic, but those get pricey if you want more than a couple.

The basic idea is there though - you want a lot of compartments in a few different sizes. Many people buy plastic storage systems, either tackle boxes or drawers (or both), in quantities ranging from "a couple" to "the entire wall of my playroom". Drawers have the advantage that they stack vertically very well, so you can fit a lot of compartments in a small-ish space, and you can get systems that lock together or attach to the wall. Tackle boxes are more portable but harder to get things out of, and organising the boxes can get ugly when you get a lot of them. But I prefer tackle boxes because they give me a wider variety of parts per area of desk, and they're portable.

Since I'm kinda crafty in other ways, I actually built my own tackle box like trays out of wood. That has the advantage that I can customise them exactly how I want them, but obviously I needed a table saw and other tools to build them. Photos here

(bigger photo)

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Tags: storage
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# Question
Title: How can I use more than three motors with one NXT brick?
I'm building Caterpillar Excavator with my NXT, and at the moment I'm trying to control 4 points of motion:

* 2 Caterpillar Tracks - These should be controlled independently to allow for cornering, etc.
* Rotation of the cab/arm
* Extension of the arm - Ideally I'd use more than on motor here, as I'd like to be able to move the bucket and segments of the arm independently, however I've got a mechanism that works to "extend and dig" in one motion.

Obviously as it stands, the NXT can only control 3 separate motors - so I'm not necessarily wedded to LEGO only solutions.

# Answer
There are electrical multiplexers as mentioned, however there are also many types of mechanical multiplexers. The idea behind this is to use fever motors to do more. The advantage is the reduced weight and the disadvantage is the increased complexity and lower flexibility.

For example, you can control both tracks with one motor. However instead of one motor making the threads more forwards and backwards, you remove the 'backwards' function and replace it with 'right-turn'. So when the motor drives forward, the bot moves forward, when the motor drives backwards, it turns right. You can't drive backwards or turn left however. A simple (but poor) implementation can be found in the R.I.S. 2.0 instructions.

While this is restrictive, you can do other similar tasks without loosing *important* functionality. Another old trick is the 'grab and lift' mechanism which both grabs and lifts an object in one movement. When you lower it again and it reaches the bottom, the grabber opens up. While you can't open the grabber while it is lifted, it normally isn't important. See The snatcher by Laurens as an example, which keeps two motors for the threads, but uses this technique to only use one motor for the arm.

Another prime example is with pneumatics, using a single motor to both pump and control a switch. See DiMastero's differential solution. It will pump no matter which direction the motor is turning, however turning it one way will push the switch in one direction, and the other when turning it the other way. (It will pump while the switch is switched from one position to another, but again, this is a minor drawback considering the gains.)

While the previous examples are solutions to specific problems, they highlight the ideas:

* Do different tasks under different situations. (Drive on clockwise, turn on counter-clockwise.)
* Chain several tasks together. (First grip, then lift.)
* Do several things at once. (Pump, while controlling the switch.)

The first point on the list, doing different tasks under different situations, is the most easy one to make a general implementation. You can split up the clockwise and counter-clockwise direction of the motors, to control two different tasks. While a bit restrictive, it is useful it certain situations.

A less restrictive solution is the 2 to n multiplexer. One motor gives the power, while another motor controls which task to transfer the power to. ('n' can be quite large, however something like 3 or 4 is more realistic in moc's.) I have come up with a few other versions, including some which allows controlling multiple motors at once (limited to same direction and speed).

**Example to your specific problem**

Use a 2 to 3 multiplexer. Output 1 and 2 controls the rotation and arm respectively. The threads are done using an adder/subtracter mechanism, use the last free motor to drive it and output 3 from the multiplexer to steer.

I would position the multiplexer above the turntable so that you just need to transfer the adder/subtracter axle through it.

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Some more examples as requested.

Here is a more advanced version of driving and turning with tracks using one motor: When the motor is turning counter-clockwise the mechanism will work like normal, driving both tracks forward. However when it turns clockwise, the yellow knob gear prevents one of the axles from moving, causing the last differential to stop and this causes both tracks to move in the opposite direction of each other, making it turn on the spot.

The knob gear is the crucial part, as it prevents action *depending* on the rotation direction. Here is a more generic version: Depending on the direction of the input, only one axle will turn.

Moving on to the actual multiplexers, here is a mock-up of a 2 to n multiplexer: Notice that the black gear can slide on the two axles, so that it can connect to both the light-gray and the dark-gray gear, depending on the position. You could have as many gears/outputs as you want in theory. I used this to create a pneumatic control station, which had 4 outputs, each controlling one pneumatic switch.

Here is a 3 to 4 multiplexer which uses transmission parts: The dark-gray axle is the input, and the 4 light-gray axles are the output. Depending on the position of the red sliders, a different output is chosen. The interesting aspect of this one is that you can have two outputs active at one time, which is not possible with the 2 to n multiplexer.

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As a final note I would like to point out that I have used all of these methods in actual RCX/NXT projects in order to do more than what I could otherwise have done with just 3 motors. They are not just theoretical solutions.

I do not see the maximum of 3 motors as a disadvantage, but as a limitation which challenges me to find other solutions to the problem so it can be done with just 3 motors.
> 28 votes

# Answer
Mindsensors sells third-party parts that are compatible with the NXT. They sell several motor drivers and multiplexers, for use with NXT motors, RCX motors, hobbyist servo motors, or by sending commands to a PF motor remote control receiver.

HiTechnic is another such company, and they likewise make a device that sends remote control signals for PF and train motors.

(It seems to me that a company in Ukraine also made a motor multiplexer, but I can't recall the details offhand).
> 13 votes

# Answer
There are two non-wireless ways that I know of.

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One of them, (which is better most likely) is to use a Mindsensors Motor Multiplexer (Motor MUX for short), which allows the use of all motor functions and splits one port into several. Note that each multiplexer requires an additional battery box, making your robot heavier and less compact. Each multiplexer costs $55, and each battery box costs $8.

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Another way is to use converter cables, and split an NXT port by connecting them like so. This technique is cheaper, and does not require an additional battery box. A drawback to using this technique is that you have less individual control over the motors. Both motors will need to turn at the same time, with the same power, and in either the same or the opposite direction depending on how you orient the connection. Furthermore, this method will negate access to the motors' rotation sensors, so movement will have to be timed.

This technique has some limitations, but if those don't matter for your creation, then converter cables are a nice and cheap alternative that helps preserve compactness. I recommend using it over the motor MUX unless your robot simply can't function under the constraints. For a demonstration of a robot using the Mindsensors motor MUX, see this video. To see a demonstration of a robot using the converter cable technique, see this video.
> 11 votes

# Answer
Everybody else has pretty much said it all, but there is one more thing I can think of.

The IR Link Sensor can communicate with Power Functions, RCX, and trains.

So you can use three NXT motors, plus, say, two Power Functions motors. (Only the NXTs will have rotations sensors, obviously.)

If you already have some PF kit, you will only need the sensor (£40). If you don't already have the remote, PF IR sensor, PF motors, and battery box, it will cost you a lot.

If you have the trains or RCX, you shouldn't need to buy anything new.

I have one of these, and use it quite a bit, it's quite a versatile piece of kit!
> 9 votes

# Answer
I built the 3 to 4 multiplexer posted above (thank you for posting that) but was able to tweak it into a 2 to 4 mux. The axles that are connected to the large gears are used to select the outputs by rotating the large gears.

It ended up being too big for what I needed though so I went a different route and built a 2 to 4 multiplexer that uses a turntable to move the drive gear around to the various outputs. You could easily add more outputs to this if you wanted. Just be aware that unlike the larger 2 to 4 mux, only one output is active at a time with the turntable mux.

The LDD files, videos of these in action, etc are on my blog:
Lego Technic Two Input, Four Output Motor Multiplexers
> 6 votes

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Tags: nxt, mindstorms, motor, design
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