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TFRPM01 - RPM Measuring Device

Overview

The TFRPM is designed to measure revolutions per minute (RPM) in UAVs. It connects directly to Pixhawk controllers like CUAV V5+ or Holybro Pixhawk 6X via a standard I²C connector and has the driver in PX4 firmware.

Specifications

Features

• Schmitt Trigger Input: To shape non-uniform signals from RPM sensing elements.
• Self-Counting and Memory: Offloads the flight controller's MCU.
• LED Indicator: Optionally visible in daylight for input status.
• Protection: Short circuit protection on the probe connector.
• I²C Connectors: Pass-through connectors for daisy-chaining sensors.
• Design: Robust and repairable.

Technical Parameters

• Pulse Frequency Range: 0 - 20 kHz.
• I2C Connector: 2x 4-pin JST-GH.
• RPM Connector: 3-pin 2.54mm pitch header.
• I2C Address: 0x50 default, alterable to 0x51.
• Operating Temperature: −20°C to +40°C.
• Input Voltage: +3.6V to +5.4V.
• Mass: 12g (4g PCB + 8g case).
• Dimensions: Case - 23.5x42x12.5mm, PCB - 37.5x19mm.
• Weather Resistance: IP40.

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Where to Get It?

TFRPM can be bought directly from ThunderFly via email contact. The email can also be used if there are specific requirements for custom modifications or if the product will be inquired in significant quantities. TFRPM is also available for online purchase through the Tindie store.

Connection to Pixhawk Autopilot

Follows the Pixhawk connector standard with specific color coding.

I²C Address Configuration

The default address is 0x50, changeable to 0x51.

Mounting Options

The device can be mounted with or without a provided 3D-printed case.

Sensor Probe Selection

Compatible with multiple probe types, including Hall effect and optical probes. See the TFPROBE01 and TFRPM01 documentation for details.

Third-party hall probe sensors could be also used, here is an example of a suitable generic hall probe with a mounting flange.

Software Configuration

Supported by PX4 firmware. Setup instructions are available on the PX4 documentation.