PCB Heart Necklace
Introduction: PCB Heart Necklace
Hey Everyone what's up!
So this is my Heart Themed PCB Necklace. The idea here was to make a necklace from PCB that glows. The concept that I used for making this Necklace was pretty simple as well.
It's basically a blinky board consisting of 36 LEDs that are controlled by an Attiny84.
Supplies
Following are the materials used in this built-
* Attiny84
* LEDs 0603 package
* 10K 0603 Resistor
* SMD Button
* Slide switch
* Custom PCB
* Arduino nano
* Coin Cell holder
* solder paste
Step 1: GETTING STARTED
I first searched for a heart image that would be suitable for adding leds and componenets, I select this image in the end.
I first imported this image on fusion360 and sketched the exposed white lines. then I used the extrude function to make this 2D Sketch into a 3D shape. now we have a 3D Heart shape that will act as a base for our PCB design,
my plan is to convert this 3D shape into a drawing and export the top layer's DXF file so my OrCAD PCB suite can import this DXF file which will be then used to make the PCB Outline and art patterns.
Step 2: Circuit Study
Now after finalizing the shape, I prepared the schematic which consists of a total of 36 LEDs, 6 LEDs are in parallel and there is a total of 6 different led setups driven by 6 different 8205S N channels MOSFET IC.
This Mosfet IC is then controlled by an Attiny84 MCU, we can change the LED Glow pattern by pressing this button. 982
After following the schematic and making a PCB Board with these components, I sent the Gerber data to PCBWAY for samples.
Step 3: Getting PCBs From PCBWAY
I received the PCBs in a week which was really fast.
I choose RED Soldermask for this project with a white silkscreen. I've Left openings in the soldermask on both sides so the LED would be visible from the topside.
The quality of the PCB I received was just awesome.
I have Been using their service for a while and I have to say, it's pretty decent for getting started. Checkout PCBWAY from here- https://www.pcbway.com/
Step 4: PCB ASSEMBLY
These are the steps for the main assembly of the FLUX CAP V3 PCB.
* Solder paste Dispensing Process
* Pick & Place Process
* Hotplate Reflow
Because this PCB Doesn't have any Through-hole component, we dont have to add any component with soldering iron, except for the Coin Cell holder on the backside.
Step 5: SOLDER PASTE
The first step is to add solder paste to each components pad one by one.
To Apply solder paste, I'm using a Solderpaste Dispensing Needle with a Wide syringe, and the solder paste I'm using is a regular solder paste consisting of 63% Tin 37% Lead.
Step 6: PICK & PLACE PROCESS
After carefully applying Solderpaste we move on to the next step which is to add componenets to their assigned location.
I used an ESD Tweezer to place each component in its place.
Step 7: HOTPLATE REFLOW
After the "Pick & Place Process", I carefully lifted the whole circuit board and place it on my DIY SMT Hotplate.
I made this Hotplate especially for making projects like these which require SMD soldering. hotplate available in the market were not exactly cheap so I made a minimal version of that which you can check out from here-
https://www.instructables.com/DIY-SMT-Hotplate-Pro...
the hotplate heats the PCB from below up to the solder paste melting temp, as soon as the PCB reaches that temp, solder paste melts and all the components get soldered to their pads.
We carefully lift this PCB and try not to shake it as the solder paste is still melted and components might move a bit from their location if shake the circuit too much.
we lift the PCB and then place it on a cooler surface for a little bit, to cool down the heat of PCB.
Step 8: LED Placement
Now here's something odd, my plan is to add leds on the bottom side of the PCB but the orientation of the LED would be inverted. which means I'm gonna add them upside down so their glow will be visible from the top.
* To accomplish this method, I have added 1206 Pads on the PCB and I'm using 0805 Package LEDs with this 1206 PAD, by using smaller LEDs, soldering them would be much easier. 472