Send and recieve for ultrasonic transducers
Since our ROV was to be an underwater craft, we figured we'd need to use ultrasonic transducers instead of infrared to make distance measurements. Not sure how infrared would work in the water, but since we had not waterproof IR sensors and just one pair of ultrasonic ones, we decided to go with the latter - even though they're not available from where we got them anymore... anyway, better than nothing.
So this about half mine - a friend had a really elaborate circuit but it was big and I thought most of it could be condensed or handled a bit different. Besides, he tried to make it and it didn't work, so I decided to start off with a revisioned design. Didn't get around to making it yet, but, provided the transducers work, I'm not too worried.
Import data for Circuit Simulator (send stage)
Import data for Circuit Simulator (recieve stage)
The send stage has a timer generating the transducers characteristic frequency (this one produces 40Khz), amplifies both sides of the waveform and sends it to the transducer. The reciever's signal gets amplified, recified and read by whoever is waiting to read it ;). The way this is supposed to work is, you start the send with an mcu and measure the time it takes for the reciever to get something. Then ofcourse you use the time to calculate distance.