patrick de groote wrote:
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Why would the transmiter need more than 50 ms for a 50 cm distance?
It's because the receiver doesn't no react to the echo without at least 50ms of sound.

What I have tried is similar like the procedures you posted. There must be sth that I don't know yet coz I've checked the program for almost 2 whole days. I've re-write the program for 3 times....


Stanley