Sunday, April 3, 2016

Smart phone stroboscope tachometer

Today, I searched over the app store for a stroboscope tachometer application to visualize oil flow and splash pattern in transparent hermetic refrigerant compressor model (typically its motor RPM is around 3000 rpm or 50 Hz) by seeing stagnant images. The idea of this category of applications is using the phone flash light as a stroboscope light and blinking it using the set frequency to act like stroboscope.  

I downloaded "Stroboscope tachometer app V 3.2" on my Lenovo A7000-a smart phone and I calibrated the stroboscope app with non-contact tachometer UNI-T UT372 and I got relatively amazing results. Since this non-contact tachometer captures the edge rise of the reflected light from the rotor, then it was good for calibration for this stroboscope app.

For my smart phone, the app worked fine up to 1000 rpm with high accuracy. By increasing the RPM the error increases in diverging way. At higher RPM values more than 1500 rpm, the application can't exceed the value of 1500 rpm with fluctuation in RPM values (this may be due to processor speed of the phone and I guess it can generate higher values on other phones with higher processors frequency).