| Circuits Designed by Dave
Johnson, P.E. : |
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Home Made Geophone Detects Foot Stomp
A home made geophone is made from a strong magnet, a coil of wire and a rubber band.
The circuit is sensitive enough to detect the vibrations of a nearby foot stomp.
It could be used as an earthquake detector. (added 7/06)
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- Human
Traffic Footstep Alarm
This circuit processes the amplified signals from the footstep detector circuit and
activates a microprocessor when the circuit detects footsteps. At has an
adjustable sensitivity.
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- Human
Traffic Footstep Detector
This circuit uses a surplus geophone to detect human footsteps from 100 feet away.
It was designed for monitoring the Mexico/USA border. This preamp part of the
system draws about 50 microamps from a 12 volt supply.
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- Pigeon
Scarecrow
I have an area on my roof where a large flock of pigeons like to roost. Their
nesting materials and droppings really make a mess. Often there is enough junk from
them that it clogs my roof gutters. Perhaps one way to scare them away is with
a device mounted on the roof near their favorite roosting spot. The device....
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