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Sensors / Detectors: Liquid Detectors
Sensors / Detectors -- Main Page
Last Updated on:
Friday, October 16, 2009 03:42 AM |
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| Circuits designed by
Dave Johnson, P.E. : |
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Electrodeless Water Level
Monitor
This system
operates much like a classic float switch but without any moving parts.
The illustration shows how a system using two copper coils sealed inside a
plastic pipe, can detect the level of water outside the pipe. Whenever
the water level is lower than the upper coil, no signal is coupled between
the coils. Once calibrated, this technique might also work on the
outside of a plastic water tank. (added 7/06)
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Water Flowing in Pipe
Indicator -- July 6, 2009
The vibrations associated with water flowing through a pipe are picked up by
an inexpensive piezoelectric wafer. The signal from the wafer is first
boosted by a micropower transistor amplifier and then fed to an ultra low
power voltage comparator. When the vibration signal has
sufficient amplitude, a FET transistor switch is activated. Drawing
only 6uA, the whole circuit is powered by a lithium coin battery, which
should power the circuit for many years....
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WATER SEEPAGE ALARM
This simple circuit sounds a beeper when its electrodes detect water. A
single 1.5v N cell powers it. A small 1.5v button battery will also work.
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Links to electronic circuits, electronic schematics, designs for engineers,
hobbyists, students & inventors:
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