Shock Sensor Question

[Phil Hunter]

IIRC from a long time ago, the minimum distance for
the Polaroid ultrasonic rangefinder is about 6 ft,
the reason being the transducer is used as both a
speaker and a microphone, and you have to allow time
for the speaker to stop oscillating before you can use
it to listen as a microphone. A couple of possiblities
to minimize the problem would be to use less power
when transmitting, perhaps to apply a burst of signal
180* out of phase to help stop the oscillations, or
use 2 seperate transducers.

regards,
phil
(digest)

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