Race Technology

There is a wheel speed sensor fitted to my car. The car has a sensor that picks up off bolts on the CV joints. It is powered with 12V. When the bolt is in proximity to the sensor a red LED lights up on the sensor. It has three wires. The obvious two and the return signal has the following characteristics. Between bolts the output is ~1.7V when the LED is on (near a bolt) the output is ~7mV (zero). The documentation states the DL1 needs at least 5V to trigger; therefore, 1.7V will not work. I wondered how I could use this. I was guessing that this 1.7V could turn on the gate of a MOSFET powered by 12V. The output could be on the upper side of the FET and have a pull to ground resistor thus pulling the output to ground until the gate turns on the it will go high.

Any other ideas?

Anyone used a wheel speed sensor from an OE ABS wheel in this capacity??

hello... any ideas on how to make this work, have the same problem myself, in an audi s3 gearbox, wtih the originale sensor suplying only 4.5V
cant get this to work with the dash2...

anyone?

You can do this in the way you describe. We have done this using a BC847 transistor. Connect the signal to the base with a 4.7k resistor, connect the emitter to ground and then put a 10k pullup on the collector to 12v, take the signal from the collector pin and you have a signal which goes between 0 and 12v for the wheel speed input. Any small signal NPN transistor will do for the job.

Martin