Thistle Design Magnetic Sensors

Thistle Design have developed a range of two channel Magnetic Sensors which can operate at Temperatures between -40ºC and +150ºC and survive severe vibration and shock loading.

Based on Hall Effect Technology these sensors have been utilised in such diverse applications as Odometers, Speed and Direction Sensors (SDS), Distance Travelled Units (DTU) and so on.

The sensors are triggered by the proximity of a magnetic material and generate a digital pulse every time such an event occurs. A rotating spur gear may be used adjacent to the sensor to trigger it and a number of applications make use of this configuration.

For example: by detecting and counting the number of teeth on a vehicle gearbox component passing the sensor, and by adding and subtracting these counts depending on the direction of travel detected by the twin channel output, it is possible to calculate the distance travelled by the vehicle.

Similarly, where access to the gearbox is restricted, it is possible to attach a toothed wheel to one of the more accessible sections of the vehicle e.g. the driveshaft, and obtain the same data as before.

For more details of the sensors and for advice on their use, please contact Bob Frew.