This mini stoplight runs on an ATTiny85, or other small MCU chip. The circuit is very simple, and is easy for any beginner to build. You can power it from a wall wart (Be careful! I burnt out 3 of them trying), or a suitable battery pack.
Print all components, and 3 Panes
If you're not using colored & transparent plastics, color in the Panes with non-washable markers.
Insert the LEDs and wire them, making room for the circuit board.
Place a cut index card between the circuit board and the LED frame to prevent shorts.
Upload the sample code, or your own to your chip of choice.
TEST YOUR VOLTAGE BEFORE POWERING THE CIRCUIT. In my experience, wall warts cannot withstand short-circuits for even a tiny amount of time. Always leave the lights running, or carefully discharge its terminals with a 10k resistor until the voltage is 0.0v.
- If all goes well, you can glue in the Panes and secure the Front and Back with screws. Also, add a zip tie to the wires on the inside to act as a strain relief.