This is the EZ4 data sheet. At 5 feet the detection path is about 2 feet wide.
How can one sense a 1/4" dowel? Remember, it is not the size of the object you are detecting, but the ultrasonic sound waves that reflect from it. If you could get a 0.001" wire to reflect enough sound energy, you can detect it. Of course, the larger the object, the further away you can 'hear' the reflected sound.
Instead of a felt cone, try a piece of pipe about 6 inches long, just large enough to fit over the sensor head. Plastic or metal, something with some density (not cardboard). That should narrow the detection width quite a lot, the issue is whether the sensor can handle the interference this will set up.
EDIT: D'oh! As a few have pointed out, I got the data sheet wrong. See below.
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20-03-2011, 10:19
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