Input lag

[Zoyx]

I'm trying to measure input lag. This is the technique I came up with on the cheap.

 

 

Camera is my Note 4 in slo-mo mode. 120 fps

Stopwatch is my Ipad mini

 

Anything I can do to improve the accuracy, but keep it on the cheap?

[Zitruskeks]

Add a LED to the circuit, so that you can actually see the exact moment when the switch toggles. This might one of the biggest accuracy improvement for little to no money as you don't depend on the "feeling" of where the putton really does the switching, as this moment is neither in the beginning nor the end of the finger movement.

 

You might want to watch the youtuber Battle(non)sense, he uses a similar setup (hacked mouse with a LED across one mouse button, a fast camera etc.) to measure input and network lag of games and also output lag of monitor technology like freesync and gsync. He describes his setup in nearly every video.