A modern adapter that allows you to use any standard Bluetooth Low Energy (BLE) keyboard with vintage Tandy Model II/12/16 computers.
• Zero-Install Web Flasher: Install the firmware directly from your browser via USB.
• Built-in Web Configurator: The ESP32 hosts its own Wi-Fi setup page for easy configuration.
• Device Scanning: Actively scans the room for Bluetooth keyboards in pairing mode.
• Dynamic Key Mapping: Remap modern F-keys or Navigation keys to Tandy’s BREAK, HOLD, ESC, REPEAT, and LOCK functions.
You will need a standard ESP32 development board. Wire the ESP32 to your Tandy's keyboard port using the following pins (make sure you disconnect the USB cable before powering on the TRS-80 or, alternatively, disconnect the 5V connection from the ESP32):
| ESP32 Pin | Signal | Function | Model II pin | Model 12/16 pin |
|---|---|---|---|---|
| GPIO 16 | CLOCK | Clock pulse | 4 | 2 |
| GPIO 17 | DATA | Serial ASCII | 1 | 1 |
| GND | GND | Common Ground | 3 | 5 |
| 5V / VIN | 5V / VCC | Powers the ESP32 | 5 | 4 |
Installation
- Plug the ESP32 into your computer via USB.
- Open Google Chrome or Microsoft Edge (Safari/Firefox do not support Web Serial).
- Visit the Web Installer Page: https://max120l.github.io/TRS-80-bt-bridge
- Click Connect, select your USB port, and click Install.
By default, the ESP32 boots in Run Mode, and actively attempts to connect to your saved Bluetooth keyboard. To change keyboard or remap keys, enter Setup Mode:
- Power on (or reset) the ESP32.
- Within the first 3 seconds of boot, press the physical BOOT button on the ESP32 board.
- The ESP32 will pause Bluetooth and start a Wi-Fi Access Point.
- On your phone or computer, connect to the new Wi-Fi network: o Network Name: Tandy Setup o Password: password123
- Open a web browser and navigate to http://192.168.4.1.
- Use the web interface to scan for your keyboard and assign the TRS-80 specific keys.
- Click Save & Reboot. The bridge will remember your settings permanently and reboot back into standard Bluetooth mode.
This bridge recreates several hardware-level Tandy functions in software:
• Hardware Repeat: If you map a key to [REPEAT] in the web config, holding that key will repeat the last character you typed.
• Shift Lock vs. Caps Lock: Standard Caps Lock only capitalizes letters. The Tandy [LOCK] key acts as a true Shift Lock, which forces the entire keyboard into a shifted state (capitalizing letters and turning numbers into symbols).