A recent MAKE project, Spooky Blinky Eyes by Bill Blumenthal, demonstrates an ATTiny45 processor fading a pair of LED eyes that randomly blink, giving a more realistic effect than standard "always on" LED eyes.
This project adapts the original code for use on the faster ATTiny85 processor and for the Arduino integrated development environment (IDE). It also adds a Cadmium Sulfide (CdS) photocell to allow the eyes to come on only below a certain light level. During sunlight, this will save battery power.
- 3 volt Trinket (there would need to be LED resistor changes for a 5 volt unit, I suggest the 3 V Trinket)
- Gemma may be substituted for Trinket
- Cadmium Sulfide Photocell
- 2 LEDs (I used two 5 mm red for the evil look, you can use any size or color)
- 2 56 or 68 ohm resistors (100 ohm will work also but eyes will be a tad dimmer)
- 1 1000 (1k) ohm resistor
- Tiny Breadboard (or other suitable wiring surface)
- 6 volt coin cell battery pack
- 2 CR2032 Batteries
- A prop to put your circuit in