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Sensors / Detectors:
Seismic Monitors,
Geophones Sensors / Detectors -- Main Page Last Updated on:
Monday, October 03, 2011 06:07 PM
Circuits Designed by Dave Johnson, P.E. :
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)
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)
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)
Links to electronic circuits,
electronic schematics, designs for engineers, hobbyists, students & inventors:
Deer Repellent (techlib) - Here is a simple sensor which can
detect the seismic vibrations caused by a person or large animal walking
nearby. A representative application for the sensor is a deer repellent
for the vegetable garden…..(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)
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.…. [Designed by
David A. Johnson]
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.…. [Designed by
David A. Johnson]
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 ….
[Designed by David A. Johnson]
Low-cost feedback circuit boosts efficiency - 01/21/99 Issue of EDN
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....Page includes several
designs. Scroll to find this one.... [Design Idea by John Guy, Maxim
Integrated Products, Sunnyvale, CA]
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)
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)
