This contactless tachometer project is based on an ATMEGA48 AVR micro controller, and is able to measure very high RPMs, as well as very low ones. It is based on an IR (Infra Red) opto-couple to detect shaft rotation.
As you can see in the short video above, the sensor is located at the back, next to a red narrow-beam LED that glows to help you point the invisible IR sensor beam to the target shaft.
The project site has code and schematics, or you can buy a kit for 29 euros.
More:
Looks like the max speed is only 35000rpm? That’s not really very high rpms. I was looking at making something that would do 100000 – 120000 rpm reliably at one point but then the need went away. I used to use two optic fibres to point the source and sensor at a shaft painted half black and half white then fed that through a simple amp into a frequency counter. Then I had a look up chart (as in manually printed out and read from!) to convert the frequency into rpm.
i need contactless tachometer kit for generator…rpm range is upto 5000 rpm…can it works? pls tell how can i purchase… mail me navas_nnn@yahoo.com
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