Hi to all,


I am doing a project contact less tachometer.The circuit is from the following link http://www.ikalogic.com/d_tach.php.But when i tested with the sensor module circuit I found that the IR diode is affected by the environment light.This is the first issue i faced. The second one i find is that the ir signal reflects from all the surface.I want a particular point from the disc to get ir reflection.for that what may be the material i should use.

thanks in advance
Afeesh

 

What i did was colour part of the surface to be checked with black paint to give a good contrast difference. The machine i use uses apulsed Ir transmitter @ 20Khz to stop the ambient light from affecting it. This was a kit i built back in 1988 as an optical pickup tacho. Its still going & could be used upto 25000RPM for checking model aero engine RPM.

 

what is the receiver module u you use.if you share the circuit diagram it will more useful.

Thanks
Afeesh

 

Here is the Tacho & article. I built this for checking shaft & Diesel engine RPM.

 

Rest of article. Couldnt get your link to work.

 

Here is the OPs link shorn of a few stray characters. http://www.ikalogic.com/d_tach.php