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Hour Meter Circuits
Last Updated on:
Saturday, June 27, 2009 04:43 PM
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Circuits Designed by Dave Johnson, P.E. : |
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MACHINE VIBRATION TRIGGERS HOUR METER
This circuit allows an off-the-shelf battery powered digital hour meter to be
turned on and off, according to a machine's operation, without requiring a direct
electrical connection to the machine. Machine vibrations are detected by an
off-the-shelf piezoelectric wafer. The wafer is normally used as a sound generator.
The 3v power could be tapped from the hour meter's own lithium battery or from a
separate 3v lithium battery. The circuit only draws about 1.5uA, so a 250mA-hr
battery would power the circuit for about 10 years.
Published in EDN, Jan 16, 1997
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Links to electronic circuits,
electronic schematics, designs for engineers, hobbyists, students & inventors:
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Machine
Vibration activates Hour Meter:
01/16/97 EDN-Design Ideas by David
Johnson Battery-powered digital hour meters commonly monitor how long a machine is in
operation by detecting when the machine is supplied with power. However, it is often
difficult or dangerous to connect a battery-powered hour meter to a line-powered
machine. When the machine being monitored produces de-tectable vibrations, you can use
the circuit in Figure 1, which doesn't require any power-line connections. The circuit
uses just one IC and allows you to turn a battery-powered hour meter on and off
according to a machine's vibration. (added 09/05) |
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