View Full Version : newbie inductive sensor

02-13-2005, 10:38 AM
I am very much an amature at basic stamps (BS2p24) and struggle to learn it although my basic electronic/electrical are very good.Anyhow I have spent quite some time trying to figure out how (internet)·to get the stamp to read/sense a signal from an inductive proximity (magnetic wirewound) sensor when being used for shaft RPM. it wil be a 2x signal @ 1000-8000·RPM so I figure a sine wave @ 30 to 300 times a second. I only need to sense differences of 200-500 RPM.·DO I use a capaciter and a resistor then use COUNT on the stamp?? I seen to have found mixed info as to weather the stamp has an onboard AD Converter. Would I be much better off going with a hall effect sensor.Also a simple sample program would be nice of you with a debug of RPM's. I hope thats not too many questions ! Thank you.

Jon Williams
02-13-2005, 10:40 AM
If you can clean-up your sine signal (make it square) you'll be able to use COUNT very reliably.

Jon Williams
Applications Engineer, Parallax
Dallas, TX· USA

02-13-2005, 11:33 AM
I don't know if a schotky will switch fast enough for you, but that's an option maybe.
Might have to amplify first before going in to that.

A Hall sensor is prepackaged and ready to go.· No fuss no muss....not sure if you have to amplify their outputs though.

A reflective pad and a phototran/op will make a reflective counter....


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Paul Baker
02-13-2005, 01:02 PM
A fast analog comparator may also work. An advantage of those over schotky is you can set the switching voltage, there are also methods for adding hysterisis like a schotky has if you so desire (switch high and switch low voltages are different, it can help with noisy signal)