:-( 5mS is about max for me (including response time of the looper)
As I said, I didn't measure it, so it could be lower... I really can't tell past a certain point. How would you measure this?
You can get the arduino to drop whatever it's doing and respond *immediately* to your button press if you use the hardware interrupt pins. The bulk of the latency would then be determined by your button debouncing... you would have to use buttons that stop bouncing very quickly to achieve less than 5ms latency.
