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Bat Detector - Circuits modified by Herb Guenther from schematic by Chris Englund
c1999 (electronic circuit added 4/05) |
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Bat detector (archilochus57) - (electronic circuit added 4/05) |
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Bat Detector Circuit (Chris Eve) - Basic tests with a variety of salvaged electret
microphones all showed good response to 50kHz and beyond, the smaller the unit the
better the response. My tests indicate that a small electret microphone has at least
some response to 100kHz and that this response is reasonably "flat" to at least 50kHz.
(design idea added 08/08/08) |
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Bat Detector Circuit (Tony Messina) - Ever since my grade school years I've been
fascinated with the way a bat uses ultrasound to "see" in the dark. The bat's
echolocation skills let it avoid small obstacles, and even catch insects, while in
flight. I learned that bats are, ultrasonically speaking, very loud --- so loud, that
some of...(added /80/80/08) |
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Bat detector microphone pre-Amplifiers - The microphone pre-amplifier has the job
of amplifying and conditioning the signal coming from the microphone. In case of an
electret microphone, the amplifier must have a gain that increases with frequency to
compensate for the low sensitivity of the microphone for high frequencies. Also the
low frequency part must be filtered out. In case of a piezo transducer, ...
(circuit added 6/07) |
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Bat detector old - (electronic design added 11/06) |
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Build a Simple Bat Detector - Ever since my grade school years I've been
fascinated with the way a bat uses ultrasound to "see" in the dark. The bat's
echolocation skills let it avoid small obstacles, and even catch insects, while in
flight. I learned ...(electronic design added 7/08) |
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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 7/03) |
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Elec Roach Motel - Using a PIC for this device provides a lot of useful
functionality.The timing for the power pulse to the inductor is critical to getting
the best Zap from your nine volt battery. The longer the current is on, the
higher the voltage. Once the inductor reaches saturation, however, you are just
waisting power.….(electronic schematic added 08/08) |
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Hap Tells His Backyard Varmints to Hit the Road - Gadget Freak Case #93: Tired of
torn-up flower beds, Hap took matters into his own hands by combining a sprinkler and
wireless driveway alert system. To allow enough time for the sprinkler valve to open,
build pressure, and activate the sprinkler head,.…. (added 05/06/07) |
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Insect Repellant - (electronic schematic / circuit added 4/02) |
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Mosquito Repellant - very simple and easy to assemble mosquito repellant using two
transistors and handy components. . (added 9/04) |
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Ultrasonic Pest Repellent - It is well know that pests like rats, mice etc are
repelled by ultrasonic frequency in the range of 30 kHz to 50 kHz. Human beings can’t
hear these high-frequency sounds. Unfortunately, all pests do not react at the same
ultrasonic frequency. While some pests get repelled at 35 kHz, some others get
repelled at 38 to 40 kHz. Thus to increase the effectiveness, …. (added 10/05) |
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Ultrasonic Pest Repellent (radioland) - Rats, mice are repelled by ultrasonic
frequency in the range of 30 kHz to 50 kHz (circuit added 11/06) |
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Ultrasonic Pest Repeller - (electronic schematic / circuit added 2/05) |
