Frequency Measure Use

[Jason Wiedmayer]

I would like to use frequency measure code to measure RPMs. The sensor is a hall effect sensor NPN/NO open collector operating at 12v (Hall effect sensor (NJK-5002c)). If I place a diode between the output of the sensor and Pin 22 on the teensy 4.1 will this generate the appropriate signal? Or should I use attached method?

 

[MarkT]

Assume the grounds are commoned?

Yes, that will work - the diode isn't strictly needed with NPN/OC but is a useful extra bit of protection (for instance
if you accidentally had a PNP output sensor it would prevent frying the T4.1)