This is basically an ATTiny85 Digispark from China (probably a clone), a laptop battery I opened up and connected 4 cells in parallel (giving 4.2v and around 4 or 5 Ah), and a PL9823, which is a cheap shift register based Chinese colour changing LED.
The LED is connected to the 5v and ground on the board, and the logic is a simple random() and switch statement. The logic is surprisingly simple, literally 4 or 5 different modes, but it looks moderately realistic. The LED is being run at about half its maximum brightness
At the minute the main concern is power. The assembly draws around 30mA, of which around 10 is the LED, 10 is the ATTiny85 chip, and 10 is the 5v voltage regulator on the board. The runtime is a couple of days.
I can reduce the ATTiny85 power consumption to 2mA by implementing a sleep mode instead of a delay(), but there doesn't seem a huge amount of point.
I'm thinking of going solar, but Ireland isn't really sunny, and theft is a real concern.
