HC-05 Bluetooth Module
This is a bluetooth serial adapter for Arduino, that can also be used for many other purposes.
It takes 5V power and IO is performed at 3.3V, so it can be connected directly to most microcontrollers including our ESP modules.
Tips and important notes:
- To put the module into AT mode, press and hold the button when turning it on.
- The module lacks reverse-voltage protection. Wiring the 5V line to ground, and ground to 5V, may destroy the module!
- Directly connecting power to the signal lines may damage the module.
- The default passcode when pairing with this module is 1234.