ModalAI ELRS Modems

Documentation for ModalAI’s range of ELRS Modems.

M0184 is a 150mW ELRS Gemini Dual 868/915MHz radio targeted for UAS receiver use.

M0193 is a 1W ELRS Gemini Dual 868/915MHz radio targeted for ground side transmitter use.

VOXL Usage

For managing ELRS firmware while connected to a VOXL, please see voxl-elrs.

ELRS Configurator and Building Code

To use ELRS configurator with M0184 and M0193, you need the ability to build custom targets in the configurator. ModalAI submitted a merge request for this feature that has not yet been merged. In the meantime, you can download a pre-built Debian package for Ubuntu Linux here which enables this capability.

Downloading Firmware

To use the ELRS configurator to build and flash a custom image of ExpressLRS for the M0184 or M0193, you will first need to download the repository for the firmware you would like to build. Navigate to the directory you would like to download the firmware into, then run the following command:

git clone https://github.com/modalai/ExpressLRS

If you would like to download the firmware for a specific version of the ModalAI firmware, you can then checkout the tag for that version. The latest tagged version for M0184 and M0193 can be found here. Versions which have ModalAI’s patches for these receivers have a fourth version number, identifying the ModalAI patch number.

Hardware Setup

The ELRS configurator requires a direct connection to your receiver in order to flash it. You can either use a USB-UART adapter connected to the TX, RX and GND pins on the reciever or connect to a Betaflight FC over USB. For ELRS receivers connecte

Setting Up the Configurator

First, ‘Expert Mode’ must be enabled in the ELRS Configurator’s settings menu.

Next, in the flashing menu, go to the ‘Local’ tab and choose the src directory of the firmware repository you downloaded earlier as the ‘Local path’.

Then, choose ModalAI 900 MHz as the ‘Device Category’ and your receiver as the device (ModalAI M0184 RX in this example).

At this point you should configure your firmware options like any other ELRS receiver, in either standard or manual mode. Please see the ExpressLRS Configurator Documentation for more information on firmware options.

You should also select the correct flashing option for your hardware setup, either UART (serial) for receivers connected directly to your device with a USB-UART bridge or Betaflight Passthrough for a receiver connected to a Betaflight FC.

Now you can press the Flash button and the Configurator will rebuild the firmware and flash your reciever.