I was thinking the other day about using a hall effect sensor to read the signal from a spark plug wire instead of using a wire wrapped around the plug wire. The only hall effect that I had was a unipolar Hall switch which is actuated with the south pole of a magnet. The sensor should turn on above 30.2 mT. I was unable to get this sensor, TLE-4906-3, to work in this situation.
Can someone explain to me what I need in this situation to make this work? I do know that the sensor operates correctly as I can pass a magnet by it, south pole activates this sensor, and light an LED, so that part is proven. Should I be using a bi-polar hall effect sensor? Should I look at the Tesla rating? Not sure where to go here.

Jen.

 

The plug wire energy is mainly in the form of voltage ... i.e. typically killivolts, but has very little current magnitude. This is why there is insufficient magnetic flux to switch on your Hall Effect Sensor.