“Which came first, the HC-05 serial-flash-hack, or the wireless Bluetooth Gamepad? ” Our guess is that [mitxela] wanted to play around with the dirt-cheap Bluetooth modules, and that building ...

The HC-05, a Bluetooth to serial bridge, can be found for around $5 on the internet and therefore may be the cheapest way to add Bluetooth connectivity to your project. However, its default setting… ...

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.