WSM – A Wireless Speedometer is a model railroad car which measures speed of a train and transmits it via Bluetooth. It is developed as a fully opensource and openhardware project. This page contains basic info about the project.

Photo of a WSM Photo of a WSM.


  • Speed-measuring based on opto-sensor.
  • Very small electronics (Size 50×18 mm).
  • Transmits data via bluetooth to any device.
  • No external power supply is required (no current from tracks).
  • Runs on battery, can measure up to 8 hours based on chosen battery.
  • Integrated charging circuit.
  • Charging from a micro-USB connector.
  • Embedded ON/OFF switch.
  • Measuring of a battery level & undervoltage protection.
  • Simple & multiplatform desktop client application.
  • Fully opensource & openhardware solution.