• Attiny85
  • Orange 3mm LED’s x2
  • 220 ohm resistors x2
  • CR2032 battery holder
  • CR2032 battery
  • SMD 2 pin button
  • 3 pin switch

Its a super simple circuit that’s more of a visual hack than anything else. I quickly breadboarded up the attiny85 with 2 LED’s and a button to just check that I was using the right pins on the attiny85 (I wanted PWM).

I asked my daughter to draw the outline of a pumpkin for the edge cuts and then on another layer and to do the face and other details which would be the silk screen on a different layer. I found it was best to export each layer as a jpeg. For full details on how to do this I’ve written up a blog post HERE.

I decided to use two 3mm LED’s one for each eye, I also added a button to that I would be able to switch between different LED modes. I kept it simple with the power, I powered it with a CR2032 coin cell. What I like about the attiny85 is that it can be powered from 2.7v-5.5v so a coin cell is more then adequate for the job. I decide to make this a wearable, I could have added a hole so it would go into a lanyard but I went the route of wearing it on a t-shirt/shirt as a badge. The good thing about using a coin cell on the back of the badge is that I could put a magnet under your t-shirt/shirt and stick it to the coin cell.

As this was going to be a soldering kit it had to be easy to solder, This is why I went with a dip8 version of the Attiny85 but it did take away from the aesthetics a little. I also went with thought hole resistors too. Too save ruining the aesthetics too much I went with a SMD button. For the switch I used a thought hole switch but on a SMD footprint but instead of putting it at the edge of the board like I normally do I put it in from the edge, I had to bend the pins for it to fit but I think it worked out quite well unfortunately it was a pain to solder.

To program the badge I used my pogo pin backpack programmer and a tinyUSB with the arduino IDE so it was easy to fix any errors while testing.


I took the code from a very old project from 2013 HERE. I had to port it to the Attiny85 and I was only using 2 LED’s but it was easy enough to do. I will post the ported code below along with all the board files to go along with it.