BETAFPV Micro RF TX module is based on the ExpressLRS project, an open-source RC link for RC applications. ExpressLRS aims to achieve the best possible link performance in both speeds, latency, and range. This makes ExpressLRS one of the fastest RC links available while still offering long-range performance.

BetaFPV ELRS Micro TX Module 915MHz Kit

BETAFPV Micro RF TX module is based on the ExpressLRS project, an open-source RC link for RC applications. ExpressLRS aims to achieve the best possible link performance in both speeds, latency, and range. This makes ExpressLRS one of the fastest RC links available while still offering long-range performance.

Specification

• Packet refresh rate: 25Hz/50Hz/100Hz/200Hz (915MHz/868MHz), 50Hz/150Hz/250Hz/500Hz (2.4GHz)
• RF output power: 25mW/50mW/100mW/250mW/500mW (2.4GHz), 100mW/250mW/500mW (915MHz/868MHz)
• Frequency bands (Micro RF Module 2.4G version): 2.4GHz ISM
• Frequency bands (Micro RF Module 915MHz/868MHz version): 915MHz FCC/868MHz EU
• Input voltage: 5V~12V
• XT30 port: 5V~12V, recommend 2S(8.4V) battery, DO NOT support 3S(12.6V) or above
• USB port: Type-C

Diagram

BetaFPV Micro RF TX module is compatible with radio transmitter which has the micromodule bay (Radiomaster TX16S, Taranis X9D, TBS Mambo etc).

Notes:

• Assemble the antenna before power on. Otherwise, the PA chip in the Micro TX module will be damaged permanently.
• DO NOT use 3S or above battery to power up the TX module via XT30 port. Otherwise, the power supply chip in the TX module will be damaged permanently.

About the Firmware

The ExpressLRS official project on Github does NOT support the OLED function for the moment. BETAFPV team will work with the ELRS team and make the official repository support the OLED and button function ASAP.

Please get the firmware from BETAFPV Github nowadays until ExpressLRS official support. In the BETAFPV branch, the ExpressLRS protocol is V1.1.0 and NO binding phrase for the firmware.

NOTE: There are 2 known issues with this firmware currently. We will solve these 2 issues ASAP. If you find more another issue, feel free to leave issues here.

• Only support pressing function for the joystick.
• When entering OLED menus page with long pressing, the connection between RF TX module and receiver will be lost, the connection will recover after exiting menus page automatically;

You could all use the ELRS official firmware V2.0-RC2 now, but lost the function of OLED and Joystick. We will work with the ELRS dev team and make the ELRS offical firmware support the full function of the Micro TX Module. For the milestone, OLED will be supported in the V2.1 officially.

https://github.com/BETAFPV/ExpressLRS

The user manual of How to Flash Firmware of ELRS RX/TX.

How do I set a binding phrase on this Micro TX module when the ELRS official mainstream does not support OLED yet?

1) First, download the source code of master-betafpv-oled-menu branch to local from Github.

2) Second, open the ExpressLRS Configurator and load the unzip source code from local. Select the target device “BETAFPV 900/2400 TX Micro”. Now, you could set up your own binding phrase and other options as normal.

3) Third, build and flash.

Basic Configuration

ExpressLRS uses the Crossfire serial protocol (AKA CRSF protocol) to communicate between the radio transmitter and the TX module. So make sure your radio transmitter supports the CRSF serial protocol. We use the radio transmitter with the OpenTX system to show how to set up the CRSF protocol and LUA script. To set this up, in the OpenTX system, enter into model settings, and on the “MODEL SETUP” tab, turn off the “Internal RF”. Next, enable “External RF” and select “CRSF” as the protocol.

ExpressLRS use the OpenTX LUA script to control the TX module, like bind or setup. With the LUA script, pilots could check, and set up some configurations of the Nano RF TX module. For more details, please check the Support Page.

• Save the ELRS.lua script files onto the radio transmitter’s SD Card in the Scripts/Tools folder;
• Long press the “SYS” button (for RadioMaster T16 or similar radios) or the “Menu” button (for Frsky Taranis X9D or similar radios) to access the Tools Menu where you can find ELRS script ready to run with only one click;
• The below image show, the LUA script run successfully;

Bind & Output Power

The Micro RF TX module comes with offically major release V1.1.0 protocol and no Binding Phrase included. So please make sure the receiver works on the officially major release V1.0.0~V1.1.0 protocol. And no Binding Phrase set. Micro RF TX module could enter binding status via ELRS.lua script, as described in “LUA Script” chapter. Besides, using the button and OLED, move to the BIND position and long-press the button. Then the RF module will enter binding status.

Note: The LED will NOT flash when entering binding status. The module will exit from binding status 5 seconds later auto. Short and consecutive press 3 times to bind.

Micro RF TX module could switch the output power via ELRS.lua script, as described in “LUA Script” chapter. Besides, using the button and OLED, move to the Output position. Long pressing the button could switch the output power.

Note: The RGB LED will NOT change according to the output power. When the output power is 250mW or above, the fan will spin automatically. The Micro RF TX module does NOT support 1W or 2W output. When switching to this value, the system will move to 500mW
automatically.

FAQ

BETAFPV ELRS Micro TX module user manual download.

Includes

• 1x BETAFPV ELRS Micro TX module
• 1x BETAFPV Moxon antenna
• 1x Micro TX module user manual
• 1x Spare USB data cable (Type-A to Type-C)

Notes:

• The antenna in the package is not the same as shown below for the 915MHz and 868MHz versions.
• The USB port housing is 6.2*11mm and may not be compatible with your own USB cables. So a spare USB data cable (Type-A to Type-C) is included in the package for all orders since November 18.
• Visit BetaFPV for more product details https://betafpv.com/products/elrs-micro-tx-module
• The antenna in the package is not the same for the 2.4GHz, 915MHz and 868MHz version.