A library to connect a Bluetooth Low Energy Keyboard and/or Mouse to ESP32, nRF51 and nRF52 series boards. It is based on NimBLE-Arduino, i suggest you read its documentation, especially if you are using a nRF board.
If you find it useful you can 
This library is a work in progress. For the moment, it only handles keyboards, and only reports HID key codes. Mice will be supported in the future. For a list of the key codes, see here: usb_hid_keys.h
#include <Arduino.h>
#include <ble_keyboard_mouse_client.h>
BLEHIDClient hid;
void on_key_pressed(bool is_modifier, uint8_t k) {
if(is_modifier) {
Serial.printf("modifier 0x%02x pressed !\n", k);
} else {
Serial.printf("key 0x%02x pressed !\n", k);
}
}
void on_key_released(bool is_modifier, uint8_t k) {
if(is_modifier) {
Serial.printf("modifier 0x%02x released !\n", k);
} else {
Serial.printf("key 0x%02x released !\n", k);
}
}
void setup() {
Serial.begin(115200);
hid.begin("BLE Keyboard demo", true, false);
BLEKeyboard& keyboard = hid.get_keyboard();
keyboard.on_key_pressed(on_key_pressed);
keyboard.on_key_released(on_key_released);
}
void loop() {
hid.loop(); // this function handles automatic connections / reconnections
}
- Interpret keycodes, make keyboard inherit from Stream so that we can do: if(keyboard.available()) { char c = keyboard.read(); }
- Add mouse support