PCB Necklace V1
Introduction: PCB Necklace V1
Hey Everyone, so here's something cool.
A PCB Necklace or Pendant powered by an Attiny13A.
The goal here was simple, to make a small Blinky board that can be attached to a chain so we can wear it like a locket or pendant.
In this Instructables, I'm gonna show you the whole build process of this PCB Necklace.
Supplies
These are the stuff I used in this built -
* 0603 Blue LEDs x24
* Custom PCB which was provided by PCBWAY
* Attiny13A
* AO3400 N channel mosfet x4
* 10K 0603 Resistor x4
* SMD Coin Cell holder CR2032
Step 1: Working of This Pendant
There are a total of 24 LEDs in this Pendant, I've divided LEDs into pairs of 4.
This means 6 LEDs are connected in parallel and they are driven by a single AO3400 N channel mosfet. there are a total of 4 of these which control 6 LED segments each. These 4 MOSFETs are then controlled by an Attiny13A, I've added a button with its D4 Pin which starts the LED sequence.
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Buy from here
Step 2: Preparing the Board
I've prepared this PCB in the shape of a tear which I first modeled in Tinkercad.
After preparing the Basic shape, I exported it into fusion360 so I could export the DXF file from it as my OrCad PCB Suit only imports the DXF file for making PCB Layer. After importing the Tear Shape in my PCB suite, I prepared the Board Schematic first that consists of an Attiny13A driving four different N-channel mosfet setup which is then connected to a total of 24 LEDs. 982
After finalizing the schematic, I exported the netlist and prepared the PCB by using the imported Tear shape as a reference.
Step 3: Schematic
Step 4: Getting PCBs From PCBWAY
After completing the design, I uploaded the Gerber data on PCBWAY's quote page, I selected the solder mask color which was RED and placed the order.
After placing the order, I received the PCBs in a week and the PCB quality was pretty great.
This shape is completely random so it's pretty hard to make but they did an awesome job of making this PCB with no error whatsoever.
You guys can check out PCBWAY If you want Great PCB Service at an Affordable rate and low price.
Step 5: ​ASSEMBLY PROCESS
After unboxing the PCBs, I started the assembly process which had the following steps.
* Solder Paste Dispensing
* Pick & Place Process
* Hotplate Reflow
* LED Testing
* Adding Coin Cell holder
* Programming
Step 6: Solder Paste Dispensing
The first step is to apply solder paste to each component pad.
I used a normal Sn-Pb solder paste which has a melting temp from 140°C to 270°C. After Adding solder paste, we move on to the next process which is the "PICK & Place Process"
Step 7: Pick & Place Process
I then used an ESD Tweeaser to carefully pick and place each component on their assigned place one by one which took like 30 Seconds tops but the result was a perfect PCB with all the components placed in their location.
Step 8: Hotplate Reflow
After the "PICK & Place Process", I carefully lifted the whole circuit board and place it on my DIY SMT Hotplate which is also homemade just like this project.
After a Few mins when the hotplate reaches the Solderpaste melting TEMP, all the components will get soldered by this Hot Reflow process. We then remove the PCB from the Hotplate to cool down all componenets and board surface.
Step 9: Testing LEDs Continuity
Because we are using LEDs here, it's crucial to check whether LEDs are soldered properly or not.
I used a normal Multimeter set in Diode checking mode, we connect the probe of the multimeter to the Anode and Cathode of leds in right polarity. If LEDs are soldered properly, all LEDs will glow. If there's any soldering error they won't glow.
Step 10: Coin Cell Holder
After testing the LEDs, we move on to the next step which is to add a Coin cell holder to the bottom layer of the PCB.
After this the board is almost completed, now we just have to flash the Attiny13A with the main sketch. 472