esp32 mqtt keyboard

Overview

This project turns an ESP32 S3 into a HID keyboard. The keyboard emulates a hardware keyboard, not a bluetooth keyboard.

• only works with an ESP32 S3 (tested) or ESP32 S2 (not tested), because the original ESP32 does not support native USB OTG
• Keystrokes can be send with MQTT commands (e.g. topic "esp32_keyboard/cmnd/UP", payload doesn't matter)

What is this good for?

• if you can't or don't want to connect an ESP32 as a bluetooth keyboard to your device, you could still connect an ESP32 S3 via USB cable
• in my case the bluetooth connection between an ESP32 and an Amazon Fire TV did not work, so I used a USB cable connection to connect the ESP32 S3 as a keyboard to control the Amazon Fire TV (if your Fire TV or Fire TV Stick has no USB port, you can use an USB OTG splitter in front of the power port).

Features are

• robust WiFi and MQTT connection. If disconnected, device will automatically reconnect
• easily expandable if more keys or special combinations of keys are needed

Media control keys

• support of so called "consumer controller" commands like PLAY/PAUSE, REWIND, FORWARD, ...
• support of special keys needed for controlling a Fire TV, like HOME, BACK and MENU

ESP32 S3 connections

The ESP32 S3 normally has two USB connectors:

• one labeled "COM": used to upload the firmware
• one labeled "USB": used to connect the ESP32 S3 as a keyboard to your device

You can have both ports connected at the same time, even to the same device.

Before uploading, I sometimes had trouble when both ports were connected before. In this case, disconnect both ports and reconnect only "COM". After uploading, you can add the connection to "USB".

Installation

I used PlatformIO IDE for installation and flashing. Please have a look at this guide. It is as simple as:

• install VSCode (Visual Studio Code)
• install PlatformIO as an VSCode extension
• clone this repository or download it
• use "open folder" in VSCode to open this repository
• check settings in "config.h"
• upload to ESP32 If you use PlatformIO, selection of the board and the USB mode is automatically done in file "platformio.ini".

You can also use the ArduinoIDE. Here you have to:

• manually install the library "PubSubClient"
• use all the files from folder "src" and put them into a folder called "esp32-mqtt-keyboard-arduino"
• rename "main.cpp" to "esp32-mqtt-keyboard-arduino.ino"
• open this folder in the Arduino IDE
• choose an ESP32 S3 board, e.g. "ESP32-S3-USB-OTG"
• Tools - "Upload Mode": "UART0 / Hardware CDC"
• Tools - "USB Mode": "USB OTG"