GPS Interface Link

Magnet actuated non-contact
displacement sensor

Scroll down for specs, installation photos and sample data

- Suspension Travel, Throttle, any other displacement
- Measures linear or rotational motion.
This sensor completely changes how suspension motion is measured in race cars!

Uses a small magnet to actuate, works with gaps up to 1 inch!
Basic Specifications:
Range: Up to 2" linear, up to 170 Degrees rotational
Sensor to Magnet Gap: up to 1"
Resolution: .02% of full scale
Repeatability: .05%
Frequency Response: 0 - 3000 Hz
Output: Voltage in the 0-5v range, see data sheet for specifics
Temperature Range:
-40 to 140 Degrees C
Full Specifications and Data Sheet:
System Compatibility: Compatible with any data system that can supply 5 volts
$225 each
Available: NOW from stock with CDS, binder, or sureseal connectors or bare wires.

Email SARA to order!


Measuring suspension motion on a push or pull rod formula or sports racer is a natural application for the SEN-15. There are many simple and easy ways to install it in such a manner that it never gets in the way of shock or ride height adjustments and in most cases gives better resolution than typical linear potentiometers.
Unlike using a rotary pot in this application, there is no need for gears to increase resolution.
Potentiometers gradually wear out, have some inherent hysteresis, and break easily in a crash.
The SEN-15 has none of those weaknesses and is LESS EXPENSIVE than most potentiometer solutions.

Here is a photo (courtesy of David Ferguson at Veracity Racing Data) showing an excellent installation of a SEN-15 on the rear suspension of a sports racer.

Note the very stout brackets for both the sensor and the magnet. It is very important to make good stiff brackets so that you are measuring the suspension movement and not the movement of the bracket!
Another view of the same installation.
Here is another great installation done by Veracity Racing Data.

This is a rear suspension bell crank on a DP02 sports racer. The sensor is mounted on the moving part (the bell crank) while the magnet is on the fixed (non-rotating) part. this is a extremely clean and simple install involving no brackets, just a few holes in the existing parts.

Rocker type suspension designs are easily handled with the SEN-15.

Here is one way to measure throttle or brake pedal movement using the SEN-15. By locating the sensor near the pivot point, large displacements can be measured. Simply install the sensor making sure you are within its limits of motion (per the Data Sheet), then calibrate in place.


The sample data shown below was recorded at Sebring. Anyone who has raced there knows it is probably the roughest track in North America. Consequently it is also the most demanding track for gathering accurate suspension data because the velocity and acceleration of suspension linkages is higher than almost any other track.

The first plot shows left-front suspension data measured with a potentiometer (green plot in top 1/2) and the SEN-15 (red plot in bottom 1/2).

This plot shows the 2 signals plotted on top of each other. Virtually identical.
The SEN-15 completely changes how suspension motion is measured in race cars!