led-guirlande - Recycled LED guirlande made with ATTiny85

LED Guirlande

Photo of the perfboard which has an ATTiny85 in a socket, a button to change modes, two buck power supply modules

This project is a little LED tinsel driver board powered by an ATTiny85 and an old laptop power supply. It drives these 12 V RGB LED strips that have a common cathode and one anode per colour (red, green and blue).

The LEDs are controlled by PWM using the ATTiny's hardware PWM blocks.

A design goal of the program is to use less than 2 Kbyte of program space, which means that it can be uploaded and used on an ATTiny25. Furthermore, as little state (and most of it is in global variables, very little RAM is used.

Building

Use the Arduino IDE (I use version 1.8.13) and make sure that you have the attiny by David A. Mellis board installed and selected. Then, select "clock: internal 8 MHz" and "programmer: Arduino ISP". Make sure to have another Arduino (such as an Uno) set up as an Arduino ISP programmer. Follow this guide for more information.

Schematic of the project