An HC-05 Bluetooth module is connected to an Attiny85, with some transistors to control a 5V power output. The Arduino takes care of a bluetooth connection and uses a serial input to control the ...

An Arduino with an HC-05 Bluetooth adapter took care of driving the LEDs and wireless communications, respectively. A wooden frame later, and the whole thing is ready to go.

The combination of a transparent OLED display, Arduino Nano Every microcontroller, HC-05 Bluetooth module, and a small LiPo battery results in a functional and versatile piece of wearable technology.