“In this Instructable we are going to take a look at using the built-in Bluetooth of the ESP32 to emulate a Bluetooth Keyboard.
Bluetooth HID (Human Interface Device) is the protocol used by regular Bluetooth keyboard and mice and its possible to emulate this with just an ESP32, which is great!
With some ESP32 development boards starting at less than $5* delivered, this is a really inexpensive and simple way to create wireless custom keyboards such as a Macro keypads. Macro keypads can be used for controlling various application like Video editors or Photoshop, personally I use mine for controlling scenes in OBS when I am making videos or streaming.
We’ll first look at how to use the ESP32 HID keyboard library and then I will show you how I used this to build a battery powered Bluetooth Macro Keypad.
TinyPICO ESP32 Dev board (Any ESP32 can work)
44 Matrix Keypad
You will also need a lipo battery, I just used a random one I had laying around so I can’t link to it!”