Digital Fireflies

I had been looking for an excuse to play with Arduinos ever since I took a bots workshop last year with John Keefe. So I decided to make digital fireflies. My plan was to tuck the fireflies into the trees at dusk while I was in Massachusetts for the weekend of the Fourth of July. 

While I was working on the project, an email chain unfolded in my inbox discussing how to boost your confidence after freelance rejections. Working on a project outside your typical skill set is one way to get out of a creative rut and feel competent about something. My goal for this project was not to have absolute fluency in drawing schematics or to thoroughly understand the ins and outs of Arduinos. My goal was to make something fun and new, to see it to completion.

Recipe 

Makes 20 fireflies

Hardware

• ATtiny85 (This is an 8-bit processor. What is a processor? Um, it’s like a thing that you put code onto to make it do something, like light up an LED light).

• RGB (red-green-blue) LEDs

• Watch batteries (This kind: 3 Volt Lithium Battery, Type 2032)

• Sockets for the ATtinies

• Battery holders (coin cell 20MM)

• Custom-designed circuit boards

Plus

• An Arduino to hook up between the computer and your ATtiny on a breadboard

• An A-to-B USB Cable

• A breadboard

• Breadboard jumper cables

• Soldering iron, solder wire, solder tip cleaning wire to help you soak up solder that you melt in place you don’t mean to (ie., touching between pins)

Software

• Eagle (John says this is “like an Adobe Illustrator for circuit boards.”)

Tasks (Top-level, with tutorial links)

1. Read this first

2. Learn how to draw a schematic

3. Learn how to use Eagle

4. Design the circuit board in Eagle (or just open the files John has on Github in Eagle and edit from there. The layers are important.)

5. Order the circuit board from Smart Prototyping. They come from Hong Kong and are pretty cheap. In Eagle, you turn the schematic into Gerber files and upload the Gerbers to the Smart Prototyping order page.

6. Once you have everything, you have to hook the Arduino up to both your computer and the ATtiny on the breadboard. Make any edits to the light pattern here.

7. Then you pop out the ATtiny and replace it with the next one, hit upload once it is hooked up to the Arduino to download the instructions onto it. Best practice is to unplug the live circuit each time before you take out the ATtiny. Do this by unplugging either the USB into the laptop, or just the jumper wire that makes it live

8. Solder each piece to each board (battery holder, ATtiny socket and LED lights)

9. Pop in the batteries when they are ready to go

10. Hang them outside

11. Enjoy!

12. Collect them all when you are done. (Mine were still going the next morning)