Diamond Shaped PCB Necklace
Introduction: Diamond Shaped PCB Necklace
Hey Everyone how's it going.
Here's something super cool, a Diamond-shaped PCB Necklace powered by an Attiny13A.
The goal here was to make a Wearable Necklace or jewelry by using a PCB and a few LEDs to make a combination of Electronics and Wearable Jewellery.
The heart of this Project is an Attiny13A that controls all the LEDs present onboard, also this pendant or necklace is powered by a CR2032 Coin Cell that is on the bottom side of the board.
This Instructables is gonna be about the whole built Process of this Necklace so let's get started.
Supplies
Following were the materials I used in this built-
* Attiny13A
* Custom PCB
* LEDs
* AO3401 Mosfet
* 10K resistors
* CR2032 Coin Cell with its holder
* Chain for necklace
* Solder paste
* Arduino Nano for Programming Attiny13A
Step 1: Schematic
The schematic of this PCB was pretty simple, I've placed a total of 12 LEDs on this board, and 3 LEDs are connected with a single Mosfet, to drive 12 LEDs, I used 4 Mosfets. Attiny13 Controls the gate of each Mosfet and we can change the state of Attiny13 by using the toggle switch.
I've also added a CON6 Header Pin for flashing the Attiny13A, I will later use my Arduino as ISP Setup to connect through this CON6 Pin and flash the Microcontroller.
Step 2: PCB Design
I prepared a Diamond Shaped PCB Board with a hole in the top for mounting the chain with this setup. I placed 3 LED Pairs on one side, I did this with the remaining 3 LED Pair and then put the attiny13A at the center part of the board.
I tried to keep this PCB as Small as possible as it's a wearable device that one will wear all day so by reducing its size, we are reducing the overall weight as well.
Step 3: PCBWAY
After completing the design, I uploaded the Gerber data on PCBWAY's quote page, selected the solder mask color which was White, 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 4: Error in the Design
Here's a small mistake I made while designing the board, I forgot to double-check the Mosfet PAD that I made for this project, I made the pad of Mosfet a little smaller than my existing footprint as this PCB was small and so I reduce the side of Mosfet Pad to save space.
I forgot to add a soldermask layer on the Pad of Mosfet that I created and this resulted in a PCB that doesnt have any Soldermask opening for soldering Mosfet with the PCB.
Wire traces were all in their place so I used a tweezer to scratch the solder mask in place of mosfet Pads and this revealed copper terminals that I can solder mosfet with.
Step 5: PCB Assembly
the PCB Assembly Process will have the following steps.
* Solder Paste Dispensing
* Pick & Place Process
* Hotplate Reflow
* LED Testing
* Programming the Attiny13A
* Adding Coin Cell holder
Step 6: Solder Paste
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 to 270 °C.
After Adding solder paste, we move on to the next process which is the "PICK & Place Process"
Step 7: Pick & Place
I then used an ESD Tweeaser to carefully pick and place each component in 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. 982