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Deer Repellent (techlib) - seismic sensor (added 8/03) |
Filter Circuit for the Earthworm Seismic Data Acquisition System - The following
design criteria were used to design the Earthworm Filter board. It had to provide low
output impedance, a low-pass filter of at least one pole, preferrably it should use
low power so that no external power would be necessary....(circuit design added
04/05/06) |
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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) ….(designed by David A. Johnson) |
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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. (added 12/04) ….(designed by
David A. Johnson) |
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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. (added 12/04) ….(designed by David A. Johnson) |
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Inexpensive seismometer project - (electronic circuit added 4/05) |
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Low cost feedback circuit Boosts efficiency - 01/21/99 EDN-Design Ideas / (added
11/05) To implement a step-up converter with a current output, designers often simply
connect the load in place of the top resistor in a resistive-divider feedback network.
The bottom resistor then serves as a current-sense resistor. Though simple, this
approach is inefficient. Low efficiency results .... |
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Seismic Alarm - My original "Deer Repellent/ Seismic Sensor" recommended using a
speaker with a weight glued to the cone as a vibration sensor (see bottom of page) but
it recently occurred to me that the speaker could supply the mass itself. By gluing...
(electronic design added (6/07) |
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Seismic Detector - The piezoelectric element of a kitchen gas lighter is used in
this simple, yet effective seismic detector. (added 4/03) |
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Seismic detector - The piezoelectric element of a kitchen gas lighter is used in
this simple, yet effective seismic detector. The piezo element must be placed
vertically, one end solidly to ground. A 2-3 pound weight of fine gravel in a loose
package should be placed on top at the other end. The high voltage lead ... (added
9/07) |
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OptoElectronic Horizontal VBB Seismometer Figures - (electronic Circuit /
Schematic added 10/04) |
