Compensate for four-wire sensor errors - Resistive pressure sensors that use two resistive elements and four wires are useful in pressure-monitoring applications. When the pressure rises, one resistance rises and the other falls. Accurate measurements with resistive sensors require compensation for losses due to wire resistance, especially when wire lengths are tens of meters. __ Designed by Septimiu Pop and Ioan Ciascai, Romania
Earthquake Alarm Circuit - Geophones are dandy motion sensors. They are metal cans containing a powerful magnet, suspended with springs inside a coil of wire. The magnet functions as a floating mass. The slightest vertical motion of the device causes the coil to move relative to . . . Hobby Circuit designed by David A. Johnson P.E.-July, 2005
Hour Meter triggered by Machine Vibration - This hobby 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 . . . Hobby Circuit designed by David Johnson P.E.-January, 1998
Hybrid vacuum tube/solid-state audio power Amplifier - 08/11/14 EDN Design Ideas: An audio power amp design that combines vacuum tube input circuitry with solid-state output and feedback components. Design by Craig D. Merz
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 piezo. . . Circuit by David Johnson P.E.-January, 1998
Motion Alarm using piezo Device - An inexpensive piezoelectric device is used as a motion sensing device for this motion alarm . . . Circuit by Dave Johnson P.E.-July 09, 2006
Optical Fiber Pressure & Motion Test - The circuit uses an off-the-shelf bright red LED light source, designed for plastic optical fibers. It also uses a matching phototransistor light detector. The devices are designed for plastic fiber. I would suggest you keep the total fiber length less than 50 feet. Bending or stepping on the fiber will produce a detectable output signal. . . . Dave Johnson, Lubbock TX-DC Magazine - Issue 15 Jan 2011
Piezoelectric Device used for Motion Alarm - An inexpensive piezo wafer is used to detect vibration and when the vibration is sufficient a switch is activated . . . Hobby Circuit designed by David Johnson P.E.-July 09, 2006
Piezoelectric Vibration Sensor Activates Switch - An inexpensive piezo device is used as a motion sensing device for this motion alarm . . . Circuit by Dave Johnson P.E.-July 09, 2006
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 by Bruce C Trump, Burr-Brown Corp, Tucson, AZ
Pressure Sensor Alarm - General purpose circuit of the simple pressure sensor alarm is built around a couple of readily available cheap components. Working of this circuit is straight forward and self-explanatory. When the circuit is powered by a 9V compact battery, the active piezo-sounder at the output of IC 1 starts beeping for a short time and __ Designed by Popescu Marian
Pressure_&_Motion_Test_for_Optical_Fibers - The circuit uses an off-the-shelf bright red LED light source, designed for plastic optical fibers. It also uses a matching phototransistor light detector. The devices are designed for plastic fiber. I would suggest you keep the total fiber length less than 50 feet. Bending or stepping on the fiber will produce a detectable output signal. . . . Dave Johnson, Lubbock TX-DC Magazine - Issue 15 Jan 2011
Pressure Sensor Alarm - General purpose circuit of the simple pressure sensor alarm is built around a couple of readily available cheap components. Working of this circuit is straight forward and self-explanatory. When the circuit is powered by a 9V compact battery, the active piezo-sounder at the output of IC 1 starts beeping for a short time and __ Designed by Popescu Marian
Pressure-Sensitive Alarm - Here is a low-cost, pressure-sensitive burglar alarm. The alarm uses a home-made pressure sensor, which works as a variable capacitor using two copper-clad boards and a piece of sponge in between...__ Electronics Projects for You
Presure based hit switch - This versatile hit switch is the electronics equivalent of a conventional switch. it can be used to control the switching of a variety of electronic devices. The circuit of the hit switch uses a piezoelectric diaphragm as the hit sensor. A piezoelectric material develops electric polarization when strained by an applied stress. The hit sensor makes use of this property.__
RS-232C port measures pressure - 08/01/97 EDN Design Ideas: 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 by W Stephen Woodward, University of North Carolina--Chapel Hill
Seismometer & structural vibration meter - 05/14/14 EDN Design Ideas: Use a TI LDC1000 as a sub-micron displacement sensor for vibration measurement and logging in seismic and structural mechanics applications. Design by Dmitrii Loukianov
Sensitive Vibration Detector - This vibration detector is realised using readily available, low cost components. One of its many applications is in a rolling shutter guard for offices and shops. The detector will sense vibration...__ Electronics Projects for You
Smart Vibration Sensor - in this vibration sensor alarm circuit, initially, when power switch S1 is flipped to 'on' position, power indicator LED1 lights up immediately. IC LM555 (IC 1) , wired as a simple latch circuit...__ Electronics Projects for You
Spice 3 Models Pressure Sensors - 01/01/98 EDN Design Ideas: Commercially available versions of Spice 3, such as isSpice4 (intusoft, San Pedro, CA) , can simulate mixed-domain systems containing electrical, mechanical, physical, and mathematical elements using behavioral models. You can use these features to simulate a variety of components. For example, the generic subcircuit in Figure 1 and the corresponding listing model the simple linear behavior of a pressure transducer. Design by Debra Horvitz, Galahad Systems, Laguna Hills, CA
Switch activated by Piezo Vibration - An inexpensive piezo wafer is used to detect vibration and when the vibration is sufficient a switch is activated . . . Hobby Circuit designed by David Johnson P.E.-July, 2006
Use RS-232C port to measure pressure - 08/01/97 EDN Design Ideas: 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 micro-machined silicon piezo-resistive pressure sensors Design by W Stephen Woodward, University of North Carolina--Chapel Hill
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