Attaching an ESP32 module into your radio only requires 4 wires.

  • Power +5V

  • Ground

  • Transmit (TX) - UART

  • Receive (RX) - UART

Power Connections

Most of the dev kits for ESP need +5v Power. You will need to find a source of 5v somewhere in your radio. Please be aware that an ESP when it's in Wifi Mode can draw a fair amount of power. Be sure where you are hooking it up can supply enough current.

On the RMTX16S, you can get power from the AUX2 header. This will be powered when the Radio Firmware is loaded with the Bluetooth option.

UART - Rx, TX Connections

On the Radio Master TX16S or other radios that have an external AUX port you can do this all from the bottom and don't have to open your radio.

In current Firmware you need to enable the Bluetooth option and it must be attached to AUX2 (Which is the bluetooth port). This is the same connection as the solder on pads inside the radio.

The pins TX and RX are attached to are available here. https://github.com/dlktdr/BTWifiModule/blob/main/src/defines.h

For a PICO board, TX is on pin 4, RX on pin 5. As shown in above example. You are going to attach, TX on ESP -> RX on the Radio RX on ESP -> TX on the Radio.

USB Port

I highly suggest keeping the USB port on your ESP Module accessible. Especially as this project grows. You will probably want to flash it and keep up to date with changes. I have notched a small hole under the side grip of my radio, So it's not visible but I can pop off the plastic and program as required.

External Antennas

Some of the onboard PCB antennas in the dev kits are not ideal and you won't get a very good range with them. I would suggest wiring in a better quality external antenna. Be sure to buy the ESP dev kit that ends with a U part number, such as the ESP32-C3-DEVKITM-1U. The U designates that it has an external antenna connector.

On the C3-MINI-1U the connector is a MHF3 or W.FL connection On the Wroom32 and Pico the connector is a MHF1 or U.FL connection

Example Setup mounted internally to a Radio Master TX16S

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