RadioMaster ERS-RC01 RPM-CDI Sensor
by RadioMaster

RadioMaster ERS-RC01 RPM-CDI Gasoline Engine Tachometer

The RadioMaster ERS-RC01 RPM-CDI Sensor is a professional-grade telemetry solution specifically engineered for the high-precision monitoring of gasoline engines in the sUAS, defense, and industrial sectors. Designed to interface directly with Capacitor Discharge Ignition (CDI) systems, this sensor provides mission-critical engine performance data in real-time. By capturing the pulse signal from the CDI speed output, the ERS-RC01 delivers accurate rotational speed data via the CRSF protocol to an ExpressLRS (ELRS) receiver. This allows pilots and sUAS operators to monitor engine RPM directly on their EdgeTX or OpenTX radio transmitters, ensuring that gas-powered propulsion systems operate within optimal thermal and mechanical parameters.

This sensor is an indispensable diagnostic tool for sUAS manufacturers, government contractors, and university aerospace departments where internal combustion engine (ICE) reliability is paramount for long-endurance missions. Monitoring real-time RPM is essential for optimizing throttle mapping, identifying engine fatigue, and preventing over-revving during critical flight phases. A standout feature of the RadioMaster ERS series is the integrated pass-through expansion port. This allows users to daisy-chain additional telemetry modules—such as temperature, GPS, or current sensors—into a single serial line, significantly simplifying the wiring architecture for complex military and commercial drone platforms.

Technical Specifications

• Model: ERS-RC01 RPM-CDI Sensor

• Operating Voltage: 5.0V to 8.4V

• Operating Current: 8mA

• Connector Type: 3-Pin JST-ZH

• Ignition Support: Standard CDI Gasoline Ignition systems

• Measurement Range: 200 to 300,000 RPM

• Measurement Accuracy: ±0.1%

• Telemetry Protocol: CRSF (ExpressLRS)

• Operating Temperature: -10°C to +85°C

• Dimensions: 28mm x 12mm x 8mm

• Weight: 6.0g

• Compatible Receivers: RadioMaster ER series (ER6, ER8, ER8G, ER8GV) and other ELRS PWM receivers

What is Included

• 1x RadioMaster ERS-RC01 RPM-CDI Sensor

• 3x High-Durability Heat-Shrinkable Tubes

• 1x Technical Reference Card