A friend that is working on a motorized Hand Crank Coil Tester had his grand daughter visiting for thanksgiving day, while on her college break.
She came out to the garage to see what he was building and he explained the problem he had with measuring the HCCT RPM rate.
She said that was a real easy problem, he only had to go to the Apple APP store, then type in strobe light tachometer and it is the first APP that comes up.
She very quickly found and downloaded the required App for him, but this would still be a problem, without an Apple phone though.
This did require a white mark to be painted on the motor pulley to check the RPMs with the strobe mark.
The Strobe Light App showed the motor was turning at 1780 RPM.