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.

A ton of ExpressLRS items are available now!

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 micro module bay (AKA JR/SLIM module bay, e.g. Frsky Taranis X9D、TBS Mambo).

Note： Please assemble the antenna before power on. Otherwise, the PA chip in the Micro TX module will be damaged permanently. 

Note：Please DO NOT use 3S or above bettery 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 offical project on Github does NOT support the OLED function for the moment. BETAFPV team will work with the ELRS team and make the offical repository support the OLED and button function ASAP.

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

https://github.com/BETAFPV/ExpressLRS

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 offical mainstream does not support OLED yet?

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

Second, open the ExpressLRS Configurator and load the upzip source code from local. Select the target device "BETAFPV 900/2400 TX Micro". Now, you could setup your own binding phrase and other options as normal.

Third, build & flash.

Know More About ExpressLRS

ExpressLRS is an open-source RC link for RC applications. Everyone could find this project on Github or join the discussion in Facebook Group.

ExpressLRS is based on Semtech Lora SX127x or SX1280 hardware for RX and TX respectively. it aims to achieve the best possible link performance in both speeds, latency, and range. At 900 MHz a maximum of 200 Hz packet rate is supported. At 2.4 GHz a blistering 500Hz is currently supported with a custom OpenTX build. This makes ExpressLRS one of the fastest RC links available while still offering long-range performance.

More and more vendors start to support the ExpressLRS radio protocol in different parts, like radio transmitter with ELRS in stock, drone with built-in ELRS receiver, ELRS TX module for JR bay, or Nano bay. BETAFPV team take part in this project and provide a series of ExpressLRS components.

Button and OLED

The ELRS TX module could be configured via the OpenTX LUA script. With OLED and button, no-OpenTX radio controller that supports CRSF could use this ELRS Micro module easily. The following no-OpenTX radio controllers work well with this TX module. Futaba T16IZ, T16SZ and T18SZ (with update to 3.9e), Wsky ET16, Radiolink AT9S Pro.

There is a 5D button on the micro module. Pay attention only the virtical dimention works and the other four dimentions are invalid. Below is the basic operation of the button and OLED.

Long Press:

In the lock screen page, long press to unlock and enter the menu page.

In the menu page, long press to change the value of this row.

Short Press:

In the lock screen page, short press invalidly.

In the menu page, short press to move to the next row.

Note：When the RF TX module is entering menus page, the connection between RF TX module and receiver will be lost, the connection will recover after exiting menus page automatically; you must re-power the receiver if you have changed the Pkt Rate.

Note: When the RF TX module enters WIFI Upgrade status, the button will be invalid. Please re-power the RF TX module after firmware update via WIFI.

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 inlcuded. So please make sure the receiver works on offically major release V1.0.0~V1.1.0 protocol. And no Binding Phrase setted. Micro RF TX module could enter binding status via ELRS.lua script, as description 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 description in "LUA Script" chapter.Besides, using the button and OLED, move to the Output position. Long press 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.

Package

• 1 * BETAFPV ELRS Micro TX module
• 1 * BETAFPV Moxon antenna
• 1 * Micro TX module user manual

The antenna in the package is not the same as show below for 915MHz and 868MHz version.