teckel:
So, the exact same processor as the Uno, darn... I'm thinking that I'll create a couple different test libraries if you're willing to try each. Probably one that replaces the ping echo detection with pulseIn to isolate the problem, then a few variations that do it a little differently.Let me know if you're willing to do this, should be really quick and simple.
Even if it's not quick and simple, I'd be happy to help.