Homemade shutter speed tester (Arduino microcontroller)

I designed and built an Arduino based shutter speed tester today.

I tested the Leica R4s, Leica M3, Rolleiflex 3.5A (recently CLA'ed) and a sad Rolleicord V.

As expected, the R4s came out best, typically 1 or 2% out from my predicted value. The Recently CLA'ed Rolleiflex was typically 15% too slow.

The M3 and the Rolleicord were way out.

 

Done