A USB device that acts as a keyboard and is a wireless-activated Rubber Ducky clone - open-source, compact, and built from the ground up using a custom embedded toolkit
Programmable color LEDs
Remote controlled programmable color LEDs with multiple effects. https://github.com/KrzysztofW/microdevt/tree/master/apps/leds-ws2812-ir-hx1838
Home alarm
AVR-based home alarm system using a reliable bi-directional RF transmission channel https://github.com/KrzysztofW/microdevt/tree/master/apps/alarm