Direction-Sensing Sonar

This direction-sensing ultrasound sonar unit uses a circuit similar to the one published by Gerry Coe, of Devantech. It uses a MAX232 to drive the transmitter in the centre, and has two receive channels, each with 2/4 op-amps in the LM324, and an LM311 comparator to sense the return.

Eventually the transducers will each be mounted on a 5cm dish for directionality - this should give about 7x gain. My MC68HC11 is capable of timing the received pulse to under 20us resolution, which can resolve 3mm differences in path length. That's enough to turn the head to "look at" a detected object. Mounted on the R/C car it will be able to watch you walk past, etc.

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