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SparkFun Anemometer With RJ11 Interface For Reed-Switch Based Wind Speed Measurement In Weather Station And IoT Projects
This anemometer measures wind speed using a simple, reliable mechanical design. Wind spins the cups on the sensor, which rotates an enclosed magnet. On each rotation, the magnet closes an internal reed switch, and the closure appears as a pulse on the output. This makes it easy to read with a digital counter or an interrupt pin on a microcontroller such as Arduino, ESP32 or Raspberry Pi Pico.
The output is available on the two inner conductors of the RJ11 connector (pins 2 and 3). To convert the pulse rate into wind speed, use the standard factor of 1 switch closure per second = 2.4 km/h (1.492 mph). This is the same anemometer supplied with the SparkFun Weather Meter Kit (SEN-15901), so it is a dependable choice for DIY weather stations, agriculture monitoring, and educational projects. It can also be bought as a replacement part.
Key Features
- Reed-Switch Output: Generates one switch closure per rotation, with no analogue conditioning needed
- Simple Speed Conversion: 1 closure per second = 2.4 km/h (1.492 mph)
- RJ11 Connector: Output on pins 2 and 3, for quick plug-in wiring
- Microcontroller-Friendly: Works with digital counters and interrupt pins
- Magnet-Based Sensing: Contactless magnetic actuation of the reed switch for dependable switching
- Kit-Compatible: Same sensor as used in the Weather Meter Kit (SEN-15901)
- Cup-Type Design: Cups catch the wind and rotate the shaft at a speed proportional to wind speed
Applications
- DIY and hobbyist weather stations
- IoT-based environmental monitoring
- Agriculture and greenhouse monitoring
- Rooftop and outdoor wind logging
- Educational and STEM projects
- Replacement anemometer for the Weather Meter Kit (SEN-15901)
