ESP32 Rainbow BLE Keyboard

A standalone firmware for the ESP32 Rainbow hardware that transforms it into a portable ultra-light touch Bluetooth Low Energy (BLE) keyboard.

Overview

This project repurposes the ESP32 Rainbow hardware — originally designed for ZX Spectrum emulation — into a BLE typing device. It features a simple text editor on the integrated display and acts as a Bluetooth HID keyboard for connecting to computers, tablets, and phones.

Features

• Bluetooth LE Keyboard: Connects wirelessly to devices as "ESP-keyboard". Supports standard typing, navigation keys (arrows), and special keys (Enter, Backspace).
• On-Device Text Editor:
  • Visual cursor with blinking and navigation.
  • Text wrapping and scrolling.
  • Multi-line editing support.
• Audio Feedback: Subtle "tick" sound on keypresses for tactile feel (using the onboard speaker).
• Touch Keyboard: Utilizes the ESP32 Rainbow's capacitive touch keyboard (V2) for ultra-light-touch key input.
• Display: Renders text and UI on the ST7789 TFT display (to be improved ...)

Hardware

This firmware is designed specifically for the ESP32 Rainbow hardware created by Atomic14.

• Project Website: esp32rainbow.com
• Hardware Repository: atomic14/esp32-zxspectrum-hardware
• Original Firmware Repository: atomic14/esp32-zxspectrum

Installation

1. Clone the Repository:

   git clone <repository-url>
   cd esp32-rainbow-keyboard

2. Open in PlatformIO: Open the project folder in VS Code with the PlatformIO extension installed.

3. Build and Upload: Connect your ESP32 Rainbow device via USB and run the "Upload" task in PlatformIO.

   • Environment: atomic14-esp32-rainbow-01

Usage

1. Power On: The device will boot up and display the text editor interface.
2. Bluetooth Pairing:
   • On your computer or phone, scan for Bluetooth devices.
   • Select "ESP-keyboard".
   • The device uses "Just Works" pairing (no PIN required).
3. Typing:
   • Type on the touch keyboard. Characters will appear on the device screen and be sent to the connected Bluetooth device.
   • Shift: Toggles upper case / symbols (hold > 1 sec. for locked mode).
   • Symb: Accesses symbol layer (hold > 1 sec. for locked mode).
   • Cursor Navigation: hold shift and press keys 1, 2, 3, 4 for Up, Down, Left, Right arrow keys (use locked shift mode on demand).
   • Backspace: hold Shift and press 0 (use locked shift mode on demand).

Dependencies

• T-vK/ESP32 BLE Keyboard
• Adafruit GFX & ST7789 Libraries
• FreeRTOS (built-in to ESP32 Arduino core)

License

GPL License

Acknowledgement

This work has been accomplished at the UAS Technikum Wien in course of the R&D-project InDiKo (MA23 project 38-09), which is supported by the City of Vienna.