ExpressLRS/ExpressLRS

STM32/ESP32/ESP8285-based High-Performance Radio Link for RC applications

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If you would like to support the development of ExpressLRS please feel free to make a small donation. This helps us buy hardware for porting, development and prototyping. Show your support for which new features you want added by leaving a message when you donate

Quick Start Guide

If you have hardware that you want to flash, please refer to our guides on the wiki, and our FAQ

High Performance LoRa Radio Link

ExpressLRS is an open source RC link for RC applications. It is based on the fantastic semtech SX127x/SX1280 hardware combined with an ESP8285, ESP32 or STM32. ExpressLRS supports a wide range of hardware platforms as well as both 900 MHz and 2.4 GHz frequency options. ExpressLRS uses LoRa modulation as well as reduced packet size to achieve best in class range and latency compared to current commercial offerings.

ExpressLRS can run at various packet rates, up to 500hz or down to 25hz depending on your preference of range or low latency. At 900 MHz a maximum of 200 Hz packet rate is supported. At 2.4 GHz a blistering 500 Hz is currently supported with a custom openTX binary with future plans to extend this to 1000 Hz.

ExpressLRS supports telemetry as optional feature. Enabling telemetry also adds support for the betaflight lua script.

ExpressLRS can be flashed into existing Frsky R9M hardware (RX and TX), Jumper R900 RXs, SiYi FM30 Hardware (Rx and TX), GHOST hardware (RX and TX) or Custom PCBs can be made if you enjoy tinkering. Happy Model released official ExpressLRS hardware (RX and TX) and several other manufacturers are preparing to offer offical ELRS hardware soon so stay tuned.

ExpressLRS aims to achieve the best possible link performance for both latency and range. This is achieved with an optimised over the air packet structure. This compromise allows ExpressLRS to achieve simultaneous better latency AND range compared to other options in the market. For example, ExpressLRS 2.4GHz 150Hz mode offers the same range as GHST Normal while delivering near triple the packet update rate. Similarly, ExpressLRS 900MHz 200Hz will dramatically out-range Crossfire 150Hz and ExpressLRS 50Hz will out-range Crossfire 50Hz watt per watt.

2.4GHz Comparison

More information can be found in the wiki.

Starting Out

After taking a look at the supported Hardware and making sure you have the required hardware, the Quick Start Guide is written to walk through the process of flashing ELRS for the first time

Supported Hardware

900 MHz Hardware:

• TX
  • FrSky R9M (2018) (Full Support, requires resistor mod)
  • FrSky R9M (2019) (Full Support, no mod required)
  • FrSky R9M Lite (Full Support, power limited)
  • TTGO LoRa V1/V2 (Full Support, V2 recommended w/50 mW power limit)
  • Namimno Voyager 900 TX (Full Support off the shelf)
  • HappyModel ES915TX (Full Support off the shelf)
  • DIY Module (Full Support, 50mW limit, limited documentation)
• RX
  • FrSky R9mm (Full Support, OTA version can be used)
  • FrSky R9 Mini (Full Support, OTA version can be used)
  • FrSky R9mx (Full Support)
  • FrSky R9 Slim+ (Full Support, OTA version can be used)
  • Jumper R900 mini (Full Support, only flashable via STLink, Bad Stock antenna)
  • DIY mini RX (Full Support, supports WiFi Updates)
  • DIY 20x20 RX (Full Support, supports WiFi Updates)
  • HappyModel ES915RX (Full Support off the shelf)
  • Namimno Voyager 900 RX (Full Support off the shelf)

2.4 GHz Hardware:

• TX
  • DIY JR Bay (Full Support, 27dBm, supports WiFi Updates)
  • DIY Slim TX (Full Support, 27dBm, supports Wifi Updates, fits Slim Bay)
  • DIY Slimmer TX (Full Support, 27dBm, supports Wifi Updates, fits Slim Bay)
  • GHOST TX (Full Support, 250 mW output power, OLED support in ELRS v1.1)
  • GHOST TX Lite (Full Support, 250 mW output power, OLED support in ELRS v1.1)
  • HappyModel TX (Full Support, 250 mW output power)
• RX
  • GHOST Atto (Full Support, Initial flashing with STLINK then both STLINK and BF passthrough)
  • GHOST Zepto (Full Support, Initial flashing with STLINK then both STLINK and BF passthrough)
  • DIY 20x20 RX (Full Support, easy to build. WiFi Updating)
  • DIY Nano RX (Full Support, CRSF Nano Footprint, WiFi Updating)
  • DIY Nano CCG RX (Full Support, CRSF Nano Pinout, STM32 Based)
  • DIY Nano Ceramic RX (Full Support, CRSF Nano Footprint, WiFi Updating, Built in antenna)
  • HappyModel PP RX (Full Support, CRSF Nano Pinout, STM32 Based)
  • HappyModel EP1/EP2 RX (Full Support, CRSF Nano Pinout, ESP8285 Based, WiFi Updating)

For a more exhaustive list refer to the Supported Hardware page on the wiki

Long Range Competition

One of the most frequently asked questions that gets asked by people who are interested in, but haven’t yet tried ELRS is “How far does it go, and at what packet rate?”

The following table is a leaderboard of the current record holder for each packet rate, and the longest distance from home. Note that not every flight resulted in a failsafe at max range, so the link may go (much) futher in some cases.

Rules

Anyone can add an entry to the table, and entries should include the:

• Max distance from home
• RF freq (900 / 2.4)
• Packet rate
• Power level
• If the link failsafed at max range
• The pilot name
• A link to your DVR on youtube (DVR is essential to compete, sorry, no keyboard claims)

Current Leaderboard

Check the wiki page for previous leaders!

Legal Stuff

The use and operation of this type of device may require a license and some countries may forbid its use. It is entirely up to the end user to ensure compliance with local regulations. This is experimental software/hardware and there is no guarantee of stability or reliability. USE AT YOUR OWN RISK