ExpressLRS is an open source long range RC system that focuses on range and latency. It’s also way more cost effective compared to TBS Crossfire and Frsky R9M. If you are looking for a cheaper way to start long range flying and prefer open source, check out ExpressLRS.
ExpressLRS offers an affordable long range alternative to the popular TBS Crossfire and Frsky R9M. They even claim to outperform these commercial systems in terms of latency as well as range!
As for now, I can only recommend ExpressLRS to the technical people because the setup is not as user-friendly as Crossfire, but hopefully it will only get better with time.
ExpressLRS Github Page: https://github.com/AlessandroAU/ExpressLRS
ExpressLRS is based on SX127x hardware combined with an ESP8285, ESP32 or STM32 for RX and TX respectively. It’s using LoRa modulation, same as ImmersionRC Ghost and Crossfire, that’s why it has noticeably better range than systems that aren’t like TBS Tracer.
It can run at maximum 200Hz update rate, if you prefer range over low latency, you can also drop it down to 100 Hz or even 50 Hz.
TX and RX modules communicate via the standard CRSF serial protocol (Crossfire) for easy use with Betaflight and OpenTX.
At the beginning, you had to build your own receiver and transmitter module (yea, not easy), but now you can just buy them off the shelf.
You can build your own receiver and transmitter module from scratch by getting the right components, ordering your PCB and solder those tiny little chips on the board. This is probably the cheapest way, a TX module and receiver costs only $30 and $15-20 respectively to build. See their Github page for more info.
You can also flash the ExpressLRS firmware to existing Frsky R9M hardware.
However, the process is irreversible, meaning you can’t flash Frsky firmware back on the hardware. Update: you can now flash Frsky firmware back on R9 hardware if you wish.
The most convenient way is to just buy the receivers (ES915RX) and transmitter module (ES915TX) made by Happymodel. They are inexpensive, designed specifically for the ExpressLRS and already loaded with the firmware, so they are plug and play.
The transmitter module is compatible with almost all modern radios with JR module bay, such as the Radiomaster TX16S, Jumper T12, T16 and T18, Frsky Taranis etc.
Here are the specs of the transmitter module and receiver:
ES915TX Transmitter Module
- Dimension: 55mm*39mm*13mm(include heat sink)
- Weight: 23gram (exclude antenna)
- Antenna connector: SMA
- VCC input: 5~13v, Recommend 5v~9v
- RF Frequency Range: 902MHz ~ 928MHz
- Maximum Output Power: <33dBm(For >27dBm operation, we recommend add a fan for force cooling)
- VCC input: 3.7~24v Recommend 5v~12v
- Operation current: ~100Ma
- Rx To FC protocol: CSRF
- RF Frequency Range: 902MHz ~ 928MHz
- Dimension: 16mm*10mm*3mm
- Weight: 0.70 gram (exclude antenna)
- Antenna connector: IPEX4
- Telemetry output Power: <17dBm
Another cool thing about ExpressLRS is its compatible receivers. Happymodel is making these tiny receivers with built-in antenna (the black tower – that’s the whole antenna) – ELRS PP, EP1 and EP2.
No more antennas hanging out getting chopped by spinning props.
As it’s going to be buried inside the frame, it probably won’t perform as well when it comes to range. But for some people this is the perfect solution if they are looking for the absolute smallest or simplest build. For example Tiny Whoops would absolutely benefit from such ExpressLRS receivers as range is not a priority but size, weight and convenience.
How to Use?
In Model settings, go down to External RF, and select CRSF. That’s it. Of course there is a lot more info on github if you want to master this system.
Telemetry is constantly being improved, currently supporting at least 14 types of data, including VBAT, current, downlink/uplink LQ and RSSI.
Telemetry screenshots from IntoFPV user Corrado-c.
ExpressLRS is available on both 2.4GHz and 900MHz so some of the tests here are done on different frequencies. Definitely a ton of potential with ExpressLRS by looking at promising test results like these :)
|Max Dist.||Freq||Pkt Rate||TX Power||Failsafe at Max Range?||Pilot Handle||Link to DVR|