Hey everyone!

So this is PANDACORN, A PCB badge that looks like a fusion between a panda and a unicorn.

It's an Attiny13A Powered PCB badge that drives 6 Blue LEDs with help of a simple Mosfet as switch setup.

The state of the mosfet is controlled by a tap of a button.

• On the first Tap, the LEDs start to Fade In and Out in a constant loop,
• On the second Tap, the LEDs start their blinking sequence,
• and on the third tap, LEDs turned LOW.

And this tapping thing goes in a loop, Tap 1, tap 2, tap 3 then repeat.

I've designed this badge in such a way that the LEDs on the bottom side will be visible from the TOP side, Not LEDs exactly but their glow is visible through PCB as I've left an opening in the TOP solder mask area and soldered the LEDs inverted, so they would shine right through the FR4 board.

I saw this technique in a PCB badge on tindie and it was looking so great so I had the idea of making a glowing unicorn horn with this same method, so I prepared this Pandacorn PCB Badge.

So in this post, I'll be showing you guys the whole built process of this PCB badge, also I have made similar projects in recent months which you can also check out if you're interested in these badge-based projects.

https://www.pcbway.com/project/shareproject/Flux_Capacitor_PCB_Badge.html

https://www.pcbway.com/project/shareproject/Ghost_Badge_made_from_555_Timer_IC.html

https://www.pcbway.com/project/shareproject/Goku_PCB_Badge.html

Material Required

• Custom PCB
• LEDs 0603 Blue
• Attiny13A
• Coin Cell holder
• A03400 Mosfet
• 10K Ohms Resistors
• USB Port
• Switch
• SMD Button

The Bill of material is attached.

Operating of Pandacorn

The state of the mosfet is controlled by a tap of a button.

• On the first Tap, the LEDs start to Fade In and Out in a constant loop,
• On the second Tap, the LEDs start their blinking sequence,
• and on the third tap, LEDs turned LOW.

And this tapping thing goes in a loop, Tap 1, tap 2, tap 3 then repeat.

Getting Started

The first step of making anything is to visualize or think about what we have to make, like in my case, I wanted to make a Panda - unicorn hybrid animal PCB, so I prepared this above illustration in which there's a panda, with a horn which he borrowed from a unicorn fella.

This horn will have LEDs on it or behind it, at first I prepared a 555 timer ic setup for the PCB but later I discarded it with the attiny13A setup below.

I prepared the schematic on my Orcad PCB Designing suite.

The setup was relatively simple, we have an Attiny13A connected with an N channel mosfet, N channel mosfet is driving 6 LEDs which are all connected in parallel with each other.

Attiny13A and these LEDs are then powered by a Coin cell or a USB pot which are both connected in parallel so two powers can be used to power this mighty badge.

Construction of PCB Schematic and Board Design

After Finalizing the schematic, I then prepared its PCB board. now for the illustration of the PANDACORN, I use a Panda image that I found on the INTERNET.

• I imported the image in my PCB Design on the top silkscreen layer so I could add a graphically pleasing image on the PCB board to make it more fun and less gloomy, more like an ART Piece.
• After getting the basic shape ready, I place all the SMD components on the bottom side of the board, from the top side, only the silkscreen will be visible and all the components will be placed on the bottom side.
• I added 0603 package LEDs in this PCB but I used a 0805 pad, this is because I will solder the 0603 LED in an oriented position with a soldering iron so it's better to add a wider pad for convenience.
• Anyway, I then connected all the tracks and completed this PCB.
• I exported its Gerber data and then send it to a PCB manufacturer for samples.

PCBWAY Review

I uploaded the Gerber data to the PCBWAY's quote page, I wanted to do something different this time so I choose the blue solder mask, I generally get PCBs in white solder masks but this time I choose a blue one.

I received PCBs in a week and the overall PCB quality was great, which was expected as PCBWAY always offers quality stuff, I've been using their PCB service for a year now, and my review of them is still the same, quality of PCBs is always high which is a plus point.

PCBWAY, well done you guys!

Check out PCBWAY for getting great PCB service at a less cost.

Assembly Process

Next is the Assembly process of this Badge, which includes -

• solder paste dispensing process
• Components Placement
• hotplate reflow
• Manually Adding LEDs
• adding THT components.

SOLDER PASTE

First, we place solder paste on each components pad, I'm using a generic solder paste (SN-Pb Ratio 63-37) with a solder paste dispensing syringe.

Components Placement

Then we add components to their assigned place one by one. You could see the schematic for the precise location of each component.

HOTPLATE Reflow

After adding components to their location, we carefully lift the PCB and put it on an 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-

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 stray from their location if moved 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.

LED Placement

Here's an additional process. 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.

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.

THT Components

After placing the LEDs, we add remaining THT components like the USB port, header pins, coin cell holder, and the power-off switch.

PCB is completed but it doesn't work just yet as we still have to flash the atttiny13A to fill it up with some sweet sweet lines of code.

Flashing Code

int switchPin = 4;     //4         

int led1Pin = 0;        //0



int brightness = 0;    // how bright the LED is

int fadeAmount = 5;    // how many points to fade the LED by





int val;                        

int val2;                       

int buttonState;                

int Mode ; //= 0;              



void setup() 

{

pinMode(switchPin, INPUT_PULLUP);    

pinMode(led1Pin, OUTPUT);

buttonState = digitalRead(switchPin); 

}



void loop(){

 

      val = digitalRead(switchPin);      // read input value and store it in val

      delay(10);                         // 10 milliseconds is a good amount of time

      val2 = digitalRead(switchPin);     // read the input again to check for bounces

      

      if (val == val2) {                 // make sure we got 2 consistant readings!

        if (val != buttonState) {          // the button state has changed!

          if (val == HIGH) {                // check if the button is pressed

            if (Mode == 0) {         

              Mode = 1;               

            } else {

                if (Mode == 1) {       

                Mode = 2;           

            } else {

                if (Mode == 2) {     

                Mode = 0;           

            } 

           }

          }

         }

        } 

        buttonState = val;                 // save the new state in our variable

      }



      // Now do whatever the lightMode indicates

      if (Mode == 0) {                       // FLIP FLOP

        digitalWrite(led1Pin, LOW);

      }



      if (Mode == 1) {

        analogWrite(led1Pin, brightness);

        brightness = brightness + fadeAmount;

        if (brightness <= 0 || brightness >= 255) {

    fadeAmount = -fadeAmount;

  }

      }



      if (Mode == 2) {

        digitalWrite(led1Pin, HIGH);

        delay(50);

        digitalWrite(led1Pin, LOW);

        delay(50);

      }

}

      

    

I have to use this Arduino as an ISP programmer to burn the bootloader of attiny and then flash it with the provided sketch.

• I've uploaded the Arduino as ISP sketch to the Arduino nano board, I've added a capacitor between its rest and GND so it won't go back into reset mode.
• then I added attiny's SPI Pins to D10, D11, D12, and 13 in the above wiring attached schematic.
• then we go to the Arduino IDE
• add the core files for the attiny.
• select the board which is in my case Attiny13
• choose the right programmer (Arduino as ISP)
• then burn the bootloader, wait for few seconds and you will be greeted with a "DONE BURNING BOOTLOADER MESSAGE"
• after this we open the sketch that we want to upload, then we go to the sketch menu, and hit upload using programmer, and our code will get uploaded to the attiny13A

POWER SOURCE

As for the Power Source of this Badge, I added a coin cell holder so I could power it with the generic CR2032 Cell, I also added a USB port to this setup so I can power it up with a 5V 1A Charger.

Both of these sources work but Coin cell is more practical as if you want to wear it with an ID Strap or add this badge on your keychain, you could just power it up with the coin cell and it will look pretty sick but a charger won't work with wearable stuff.

END RESULT

Badge working is also pretty kool, we first turn ON the Badge with the Toggle switch, then we Tap the Button once and Badge starts its fading sequence, the second Tap will switch the Fade to a fast blinking sequence and at last, the Third Tap will turn the LEDs to LOW State.

then this process goes into a Loop, TAP1>TAP>TAP3- LOOP

LEDs are visible through the FR4 board which makes this badge even better.

For now, I haven's made any mistake in this PCB version so I don't think there will be another revision of this pandacorn badge but maybe I could prepare a 555 timer ic pandacorn version to reduce its overall cost as using atttiy13A added 1$ to the bill of materials.

Anyways's this is it for today guys, stay safe, and I'll be back with another project soon, Peace Out!