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Pressure Gauge Responds Linearly to Altitude - 03/03/94 EDN-Design
Ideas....You can use a common pressure transducer as an altimeter if you employ a
special technique to make the transducer respond linearly. If you were to simply
amplify the output of a pressure gauge's bridge (VB in Fig 1]by a gain of 32.7 and an
offset of 3.2V, such a circuit would produce an output of0V at sea level and 1V at
10,000 ft. However, this simple design would read 38.5 mV (385 ft], which is too high
at 5000 ft. The nonlinear relationship between atmospheric pressure and altitude
causes the error, which peaks at 3.85% of full scale.... [Design Idea by Bruce C
Trump, Burr-Brown Corp, Tucson, AZ] |
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Pressure Sensor-Based Altimeter Circuit - (electronic circuit added 4/05)
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Use RS 232C port to measure pressure - 1-Aug-97 Issue of EDN A simple
circuit and accompanying software turn a pressure sensor into an accurate and cheap
pressure digitizer that works with any PC's RS-232C COM port. Many manufacturers make
micromachined silicon piezoresistive pressure sensors.... [Design Idea by W Stephen
Woodward, University of North Carolina--Chapel Hill] |
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555 Based IR Proximity Detector - Sometimes you want a simple solution to a
problem and you don't mind if your main controller has to do the work. This IRPD
requires the main robot processor to choose which side to look at, and....(added
05/06/07) |
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555 Based IR Proximity Detector - Several robotic projects on the page,
please scroll to find this one. [Dennis Clark's website] |
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Doorknob Proximity Alarm - Reverse engineered circuit diagram of a popular
retail doorknob alarm. It contains a small transmitter and the doorknob acts as an
antenna so it will not work on a metal door. When a person comes close to the doorknob
this loads down the oscillator and the alarm sounds. The proximity sensor circuitry is
perfectly capable of driving 74HCT series CMOS logic instead of the noise maker IC's
shown in the circuit diagram. (added 2/05) [Reverse engineered schematic by
Stepan Novotill] |
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DTMF Proximity Detector - .... |
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Dual Comparator - forms temperature-compensated proximity Detector (app note
added 8/03) |
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Dual comparators stabilize proximity detector - 02/16/98 EDN-Design
Ideas....In the proximity detector of Figure 1, a 4-in.-sq piece of copper-plated pc
board serves as an antenna that forms one plate of a capacitor. An approaching
(grounded] person serves as the other plate, producing a capacitance value.... [Design
Idea by Arthur Harrison, US Army Research Laboratory, Adelphi, MD, and Joseph Stern,
Maxim Integrated Products, Sunnyvale, CA] |
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High-speed op amp enables IR proximity sensing - 6-Aug-09 Issue of EDN
The amplitude of a modulated signal indicates the distance of an object from the
sensor.... [Design Idea by Arpit Mehta, Maxim Integrated Products Inc, Sunnyvale, CA] |
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High-speed op amp enables IR-proximity sensing - 06-Aug-09 Issue of EDN
IR (infrared]-proximity sensors can sense the presence of an object, its distance from
a reference, or both. Applications include speed detection, sensing of the hand in
automatic faucets, automatic counting or detection of objects on conveyer belts,….
[Design Idea by Arpit Mehta, Maxim Integrated Products Inc, Sunnyvale, CA] |
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Infra-Red IR Beam Alarm/ Proximity Detector - This circuit can be used as an
Infrared beam barrier as well as a proximity detector. The circuit uses the very
popular Sharp IR module (Vishay module can also be used). The pin nos. shown in the
circuit are for the Sharp & VIshay modules. For other modules please refer to their
respective datasheets. The receiver consists of a 555 timer IC working as an
oscillator at....(added 11/06) |
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Infra-red Liquid Level Detector - Useful for liquids level detection and
proximity devices Up to50 cm. range, optional relay operation (added 4/05)
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Infrared Motion Detector - Pyroelectric infrared sensor and associated
circuits detect infrared radiation from human or animal body. General purpose motion
detector with normally open relay output. 16 pages. [free circuit from Golab.com] |
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Magnetic Proximity Sensors - Here is an interesting circuit for a magnetic
proximity switch which can be used in various applications. The magnetic proximity
switch circuit, in principle, consists of a reed switch at its heart. When a magnet is
brought in the vicinity of the sensor (reed switch), it operates and controls the rest
of the switching circuit....(added 09/05) |
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Model Railroad Infrared Proximity Switch - Circuit for model railroad
trains…. [from Rob Paisley's Model Train web site] |
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