This is a simple example of a BLE keyboard using the Lolin32 board and the ESP32's bluetooth stack.

The code is pretty simple. It uses the ESP32's bluetooth stack to create a BLE HID device.

The device can send 3 keys: a, b and c.

The keys are sent when the corresponding button is pressed (or in my case, when the corresponding pin is grounded).

The built-in LED is turned on when the device is connected and turned off when it is disconnected to bluetooth.

Three separate LED's are turned on when the corresponding button is pressed: i.e. a button turns on the left LED, b button turns on the middle LED and c button turns on the right LED.

(In reality, there are three LEDs connected in serial for each one on the diagram - I don't have any resistors)