Do you like jewellery? And what about electronic jewellery with some light effect?
I made a small batch of electronic earrings. They are fitted with 18 red LEDs, MCU (STM32F030), battery and slide switch. The lighting effect is very decent. I didn't want them to look like a "disco ball". Firmware is programmed over pogo pins next to battery and battery lifetime is about 20 hours.
