Polaris ATVs have hall effect sensor next to the brake rotor. It senses the holes in the rotor as it rotates to give speedometer readings. A new one is around $100.00. I found some generic ones ebay for around 4 bucks, both have 3 wires. Will this work in my application or are there specific differences with these sensors. There are no magnets in the brake rotor that I can see, do some sensors require magnets to operate? Thanks

 

If the original doesn't use a magnet then it is a type known as a reluctance sensor which have an internal magnet and sense with a coil.
https://en.wikipedia.org/wiki/Variable_reluctance_sensor. A hall effect sensor needs a magnet attached to the moving part.

 

..... or if the moving part is itself magnetised it can operate a Hall effect sensor.

 

From the spec sheet.
"This Inductive Proximity Switch Sensor is ideal for detecting the presence of ferrous or magnetic objects to determine rotational speed, the presence or absence of parts, or position limits."

Appears to be a ordinary NPN open collector proximity SW..
Max.

 

From the spec sheet.
"This Inductive Proximity Switch Sensor is ideal for detecting the presence of ferrous or magnetic objects to determine rotational speed, the presence or absence of parts, or position limits."

Appears to be a ordinary NPN open collector proximity SW..
Max.

Do you think it is it worth a try?

 

You need the right type of sensor. They do cost more. I converted some devices a few years ago from variable reluctance to hall based sensors so we could slowdown the rotational speed. A uC was used to reproduce the original higher speed pulses needed by the rotation detection board.
https://github.com/nsaspook/mass_slit/blob/master/Slow_RMS_DOC.pdf

https://sensing.honeywell.com/LCZ260-hall-effect-digital-speed-sensors

 

Do you think it is it worth a try?

If the rotor holes are the right spacing it should work.
There is also the gear tooth sensor used for automobile timing etc, MicroSwitch make one 1GT101DC also automotive wreckers are a source.
Max.