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 can be flashed into existing Frsky R9M hardware (RX and TX), Jumper R900 RXs, GHOST ATTO/ZEPTO Receivers or Custom PCBs can be made if you enjoy tinkering. Several manufacturers are preparing to offer offical ELRS hardware soon so stay tuned.
ExpressLRS aims too achieve the best possible link preformance for both latency and range. This is achieved with an optimised over the air packet structure. However, only basic telemetry is currently provided (VBAT, downlink/uplink LQ and downlink/uplink RSSI), work is underway for full telemetry support. This comprimise 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.
Development is ongoing but the following hardware is currently compatible
Frsky Hardware
| RX/TX | Hardware | Status | Notes |
|---|---|---|---|
| TX | 2018 R9M | Fully Supported | Requires resistor mod for lowest latency |
| TX | 2019 R9M | Fully Supported | Resistor mod not required |
| TX | R9M Lite | Fully Supported | Limited to 50mW |
| TX | R9M Lite Pro | In Development | |
| RX | R9MM | Fully Supported | |
| RX | R9MX | Fully Supported | |
| RX | R9mini | Fully Supported | |
| RX | R9slimplus | Fully Supported | |
| RX | R9slimplusOTA | Fully Supported |
Jumper Hardware
| RX/TX | Hardware | Status | Notes |
|---|---|---|---|
| RX | R900 mini | Fully Supported | Can only be flashed via stlink, BAD included antenna |
ImmersionRC Ghost Hardware
| RX/TX | Hardware | Status | Notes |
|---|---|---|---|
| RX | Ghost Atto | Fully Supported | Can only be flashed via stlink |
| RX | Ghost Zepto | Fully Supported | Can only be flashed via stlink |
DIY 2.4GHz Hardware
| RX/TX | Hardware | Status | Notes |
|---|---|---|---|
| TX | ESP32 Module (E28 SX1280) | Fully Supported | Flashable via USB, 250mW max |
| TX | ESP32 Module (F27 SX1280) | In Testing | Flashable via USB, 250mW max |
| TX | ESP32 Module (Bare SX1280) | Fully Supported | Flashable via USB, 20mW max |
| RX | 20x20mm RX | Fully Supported | Supports WIFI Updating |
| RX | Nano RX | Fully Supported | Supports WIFI Updating |
| RX | CCG Nano RX | Fully Supported | No WIFI, STM32 Based |
DIY 900MHz Hardware
| RX/TX | Hardware | Status | Notes |
|---|---|---|---|
| TX | DIY Module (RFM95 Module) | Fully Supported | Flashable via USB, 50mW max |
| TX | TTGO V1 Dev Board | Fully Supported | No longer recommended |
| TX | TTGO V2 Dev Board | Fully Supported | Supports WIFI Updating, 50mW max |
| RX | DIY mini RX | Fully Supported | Supports WIFI Updating |
| RX | DIY 20x20 RX | Fully Supported | Supports WIFI Updating |
Links:
- Nano 2.4GHz RX Currently Smallest DIY 2.4Ghz RX
- 20x20 2.4GHz RX Convenient Stack Mounted DIY 2.4GHz RX
Links:
- Mini 900MHz RX Currently Smallest DIY 868/915MHz RX
- 20x20 900MHz RX Convenient Stack Mounted DIY 20x20mm 868/915MHz RX
- 20x20 900MHz RX Convenient Stack Mounted DIY 20x20mm 868/915MHz RX
One of the most frequently asked questions that gets asked from 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.
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)
| Max Dist. | Freq | Pkt Rate | TX Power | Failsafe at Max Range? | Pilot Handle | Link to DVR |
|---|---|---|---|---|---|---|
| 30Km | 900M | 50HZ | 1W | No | Snipes | https://www.youtube.com/watch?v=SbWvFIpVkto |
| 10Km | 2.4G | 250HZ | 100mW | No | Snipes | https://youtu.be/dJYfWLtXVg8 |
| 6Km | 900M | 100HZ | 50mW | No | Snipes | https://youtu.be/kN89mINbmQc?t=58 |
| 4.77Km | 900M | 200HZ | 250mW | No | DaBit | https://www.youtube.com/watch?v=k0lY0XwB6Ko |
| 2.28Km | 900M | 50HZ | 10mW | No | Mike Malagoli | https://www.youtube.com/watch?v=qi4OygUAZxA&t=75s |
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
