Modifying to Torque Sensing

[saneagle]

Will I break it if I get the wires round the wrong way?

No, it's only 5v; however, if you leave the 5v wire connected to ground for a long time, it'll eventually blow the 5v regulator in the controller.

 

[JohnD135]

Thanks saneagle. Throttle now functions as expected and I get rotation of the rear wheel. Now looking at the feed to the PAS. I assumed it would be a reed switch but i am measuring 5 volts wrt to the other two pins and also slightly negative. What is the device please? I had no idea that Hall effect detectors were so linear. 1% or so.

 

[Nealh]

PAS is also Hall effect.
The pulses between 5v and Signal to activate movement as the magnet disc passes the Hall Sensor.

 

[saneagle]

Thanks saneagle. Throttle now functions as expected and I get rotation of the rear wheel. Now looking at the feed to the PAS. I assumed it would be a reed switch but i am measuring 5 volts wrt to the other two pins and also slightly negative. What is the device please? I had no idea that Hall effect detectors were so linear. 1% or so.

There are two types of hall sensors: Bi-polar ones (SS41)are on/off 5v and switch when a magnet passes. They're typically used as positional or rotation sensors. Linear hall sensors (SS49) give a 1.2v to 3.8v variable output depending on the strength and orientation of the magnetic field. They're typically used for throttles.

 

[harrys]

This is a typical Hall sensor throttle. Just a 3 pin IC that faces the magnet bar.

Close up of the magnetic sensor chip. It gets ground, power and puts out a varying DC signal between 0.7 V and around 4.3V.

One potential fail is if the ground wire breaks, the signal goes up to 4.3V and the controller thinks you want full throttle. Happened to me twice, but on bikes that had small motors, so I didn't realize the throttle was on til I started coasting.