Garrison Regiment PCB Badge From Attack on Titan

Hey Everyone what's up!

So this is my Garrison Regiment-themed PCB Badge from Attack on titan. Garrison Regiment is one of the three Regiments in attack on titan anime that protects and maintains order within the Walls.

The goal for making this badge was simple, I wanted to make some kind of AOT-inspired project that I could keep in my Project collection.
I also prepared two more Badges from AOT which were themed after the other two remaining divisions which are scouts and military police.

https://www.instructables.com/Wings-of-Freedom-PCB...

https://www.instructables.com/Attack-on-Titan-Mili...

These were the things I used in this Badge Project-

• Custom PCB (which was provided by PCBWAY)
• Resistor 10K 0603 Package x 1
• Resistor 2R 1206 Package x 1
• Attiny13A SOIC8 x 1
• SMD LEDs 0603 Package x 15 (Color will be RED)
• Arduino for Programming the Attiny13A
• Solder paste
• Coin Cell holder
• CR2032 Coin cell
• Slide switch
• Hotplate reflow

My reason for choosing PCBs as a base for this project was also pretty simple if we are making some kind of illuminating device that is meant to be a wearable thing, Using a 3D Printed body with electronics adds too much weight to the whole project and its easier to lay down everything on a PCB and use it as a whole thing instead of making an enclosure for it.

To prepare this Garrison badge, I first had to find a black and white image of the badge and then convert it from any format into BMP.

BMP because I will be using my OrCad PCB Suite which only imports images in BMP format, so after converting the image into BMP, I uploaded it into my Cad suite as a TOP Silkscreen layer.

Now what I want to do here is, I will be adding a few 0603 package LEDs from the backside to illuminate the rose shape in front.
To transfer the Glow of LEDs from the backside to the front side, I used one of my classic tricks which are to remove solder mask from the top and bottom side and solder LEDs in an inverted position so their glow will face the FR4 board, we can see the glow from the Front side.

To do that, I had to manually fill each area of the Rose pattern which is on the front side with an irregular shape of Soldermask Top openings.

I did the same on Soldermask Bottom but instead of making the Soldermask Openings of each rose area, I made a huge opening as this side won't be visible from the Top, we are making this opening to let the light from LEDs get past the FR4 Board. By doing this, we will be able to see illuminated Rose from the front side without adding any components on TOP Side.

To Drive all the 15 LEDs, I use an N Channel SMD Mosfet which is AO3400, its gate is connected with an Attny13A.

We use the Attiny13 to control the gate of mosfet to fade or blink the LEDs.

the schematic of this project is attached above.

I've made this designed in such a way that if we dont want to add any Blink or fade sequence through using Attiny, we can skip the MCU and Mosfet by shorting R6 and this will connect LEDs directly with the Coin Cell holder.

By Shorting R7, we can connect this setup with Attiny and mosfet.
I believe badge projects should be simple as possible so anyone can make them on their first try which is the whole point of making this project. Adding Functions like glow and fade or multiple LEDs will increase the aesthetics more but using an ESP12F or Higher MCU for a simple blinky board seems very overkill. An Attiny85 can be used here as an Alternative as Attiny13A isn't powerful enough for driving RGB Neopixel LEDs.

After Finalizing the PCB, I sent the Gerber data to PCBWAY for samples.

I choose RED Soldermask for this project, this was my first time getting RED soldermask PCB from PCBWAY and the quality of PCBs was just great.
Been using their service for a while and I have to say, it's pretty decent for getting started.

Just see the intricate design of mine, I placed many unusual patterns on the PCB like irregular outline and shape of soldermask which is hard to make but they did an awesome job of making the PCBs with no problem whatsoever.
Checkout PCBWAY from here- https://www.pcbway.com/

Lets now start the assembly process which includes the following steps-

• Solder paste Dispensing Process
• Pick & Place Process
• Hotplate Reflow soldering Process
• Placing LEDs manually
• THT Componenets soldering

Now let's get started with the first step which 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.

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. Also, I'm placing a Brooch pin through solder paste. In previous badge projects, I've always considered Brooch Pin as a THT Component that can only be added to its copper pad with a soldering iron but as it turns out, we can use a normal hotplate to melt the solder paste and it will bind the brass material properly without overheating.

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...

But anyway, 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.

After Reflowing the PCB, we now have to add leds to the board.

we have to add LEDs in an oriented position, which means that we have to turn the LED 180 degrees and solder it to the provided pads one by one with a soldering iron.

For soldering each led, I followed these steps-

• To solder each led, I first added solder to one side.
• then we pick and place the LED in its place and melt the solder we just placed and it will hold the led in its place from one side.
• we then add solder to the other pad and this will secure the led from both sides and the led will be completely held down on its pad.
• Now we solder the rest of the LEDs one by one by following the same method.

Precaution here is to not overheat the LED or it will melt, just be quick and use a lower temp like 280 degrees to melt the solder paste or solder wire.

After Soldering all the LEDs, we test their continuity with a multimeter set on the Diode checking mode.

we place the probe of the multimeter onto the anode and cathode of any LED.
Because all LEDs are connected in parallel, all LEDs should glow, if any led is not glowing, this means there's a connection error, correct that error and move on to the next step which is the THT Components placement.

After placing the LEDs, we add the remaining THT components which are the Coin Cell holder and a Slide switch with a soldering iron.

After adding the THT Componenets, our circuit is completed. The Circuit is completed but to make it work, we have to burn the sketch into the Attiny13 MCU.

This is the code that I used in this project, it's a Fade sketch that fades D0 of Attiny13 from the least value to the max which is 0-255.

int led = 0;    //D0     
int brightness = 0;  
int fadeAmount = 5;   

void setup() {
  pinMode(led, OUTPUT);
}

void loop() {
  analogWrite(led, brightness);
  brightness = brightness + fadeAmount;
  if (brightness <= 0 || brightness >= 255) {
    fadeAmount = -fadeAmount;
  }
  delay(100);

Before starting the Flashing process, we first need to download and install the Attiny13 Core files in Arduino IDE.

https://github.com/MCUdude/MicroCore

• Open the Arduino IDE.
• Open the File > Preferences menu item.

• Enter the following URL in Additional Boards Manager URLs: https://mcudude.github.io/MicroCore/package_MCUdud...
• Open the Tools > Board > Boards Manager... menu item.
• Wait for the platform indexes to finish downloading.
• Scroll down until you see the MicroCore entry and click on it.
• Click Install.After installation is complete close the Boards Manager window.

AVRs chips usually come blank, they need to be set up to be Arduino IDE compatible but to do that you need an AVR programmer do to that, for example, a USBASP.

Fun Fact, you could make your own AVR Programer with an Arduino Uno or a Nano board in a very easy step.

• Connect your Arduino board with com port and select Example>ArduinoISP, upload this sketch onto your board.
• After uploading, go to the tools menu and choose the Arduino as ISP option in the programmer section.
• Now for flashing Attiny13A, we can select the Attiny13A in the Board section.

The programming process uses VCC, GND, RST, MISO, MOSI, and SCK.

• 5V of Arduino to VCC of Attiny
• GND to GND
• D10 of Arduino to RST of Attiny
• D11 of Arduino to MOSI of Attiny
• D12 of Arduino to MISO of Attiny
• D13 of Arduino to SCK of Attiny

Wire the Attiny13 with Arduino in the above way. (also right after uploading ISP Sketch to your Arduino, do not forget to add a 10uf Cap between Reset and GND pins of your Arduino board)

Instead of using an Arduino Nano and a breadboard for this job, I will use my DIY Attiny Programmer which I made for flashing the Attiny or Atmega MCUs.

Instead of Wiring, it utilizes a SOIC8 Clip to make the connection between the Arduino board and Attiny MCU. It's pretty much the same as the above wiring Schematic.

Also, I've added 6 Dip8 Sockets in parallel with each other to program more than one attiny at a time. Check out more about this Programmer from here-

https://www.instructables.com/Multiple-ATtiny8513A...

• connect the Board to the Arduino as ISP Setup in the above wiring config
• choose the right port, right programmer (Arduino as ISP), and hit Burn Bootloaderwait for a few seconds, you will get done burning the bootloader message.
• Now Open the sketch that you want to upload to this AttinyGo to the Sketch menu and select Upload using the programmer.
• and your Sketch will get uploaded onto the attiny13.

And as you can see, the badge is working!

The fade rate is pretty slow as I've changed its time delay, this can be altered by changing the delay from 1000 to 500 or less. Also, because of Brooch Pin, I added this badge to my Backpack as it's more practical to add it to the bag instead of wearing it all time.

The conclusion of this badge project is this- It's possible to make anything into a PCB Design, we just need to get a Black and white image of XYZ stuff and we import it into our PCB Design and place componenets around that design, Adding LEDs will increase its overall impact and aesthetics.

I Previously made two more PCB Badges from the same show Attack on Titan. Those two badges work similarly to this one.

https://www.instructables.com/Attack-on-Titan-Mili...

https://www.instructables.com/Wings-of-Freedom-PCB...

This is it for today guys, thank you so much for reading this article, and I'll be back with another project soon!

Happy holidays!