Project archive guide. Technical instructions are awaiting hardware-team review; consult the documentation for your exact equipment.
ExpressLRS
ExpressLRS (ELRS) is an open-source, high-performance radio control system designed specifically for long-range and low-latency FPV drone flying. It offers pilots a robust, highly customizable connection between the transmitter and receiver, capable of delivering fast response times and excellent signal reliability even in challenging environments. ELRS is quickly becoming the favorite protocol in the FPV community thanks to its flexibility, low cost, and frequent firmware updates.
Key Components & Concepts of ELRS
Transmitter Module
A small radio module that plugs into your RC transmitter, running ELRS firmware to send control signals over 2.4GHz or 900MHz frequencies.
Receiver (RX)
Mounted on your drone, this hardware receives ELRS signals, interprets them, and sends control commands to the flight controller.
Frequency Bands
ELRS supports both 2.4GHz for typical FPV flying and 900MHz bands for ultra-long-range setups, giving pilots versatile options based on their needs.
Latency & Refresh Rate
ELRS can operate at very low latencies (as low as 2ms) and high packet rates (up to 500Hz), resulting in responsive and precise control.
Open Source Firmware
The ELRS project is community-driven, allowing frequent updates, customization, and support for a wide range of hardware.
Binding
The process of linking your transmitter module to the receiver, creating a secure communication channel.
Telemetry Support
ELRS supports two-way telemetry, allowing the pilot to receive real-time data such as battery voltage, signal strength, and GPS info.
Transmitter Module Explained
The ELRS transmitter module fits into the JR-style module bay on your RC transmitter. It sends control commands using configurable frequencies and power levels. You can flash different firmware versions via a USB interface for improvements or custom setups. Why it matters: This module replaces older RC protocols with faster, more reliable links at a fraction of the cost.
Receiver (RX) Role
The receiver on your drone converts ELRS radio signals into PWM, SBUS, or CRSF signals the flight controller understands. ELRS receivers are small and lightweight, perfect for micro and racing drones. Note: Some ELRS receivers support SmartPort telemetry for bidirectional data flow.
Frequency Bands: 2.4GHz vs 900MHz
2.4GHz ELRS modules are common for typical FPV flying, balancing range and latency. 900MHz modules offer much longer range but require larger antennas and can be bulkier. Choosing the right band depends on your flying style and environment.
Latency & Refresh Rates
ELRS supports packet rates from 10Hz up to 500Hz, with latencies as low as 2ms, giving near-instant response to stick inputs. High refresh rates improve control smoothness, essential for freestyle and racing pilots.
Binding Process
Binding creates a secure link between your transmitter and receiver. ELRS simplifies binding through a dedicated button on the receiver and configurable software options on the transmitter module. Tip: Always bind before flying to prevent control loss.
Telemetry Benefits
Two-way telemetry allows your drone to send critical data back to your transmitter in real time, such as battery status, signal strength, and GPS location. This helps you monitor flight health and avoid surprises mid-flight.
Open Source & Community Driven
ELRS firmware is open source and regularly updated by a passionate community, ensuring compatibility with new hardware and constant performance improvements. Pilots can customize settings, optimize for latency or range, and contribute to ongoing development.