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Battery-Powered Sensor Detects Dangerous UV Radiation - 12/08/94 EDN Design Ideas: The battery-powered circuit in Fig 1 detects 295-nm UV radiation, which is dangerous to eyes and skin. Be sure to protect yourself and your coworkers against this radiation. To operate device, press switch S1 and hold it closed for at least 2.2 sec. A start pulse applied to IC 4 starts 2.2-sec measuring cycle. Pin 3 of IC 4 resets 4040 binary Design by Joerg Hollmann and Hughes Leitz, ON, Canada
Biasing Corrects Position-Sensing Photodiode - 07/07/94 EDN Design Ideas: An integrator powers the light source in Fig 1's position-sensing circuit, eliminating errors arising from variations in the source's intensity. This circuit's accuracy is essentially that of the sensor itself, beating designs that use a more complex anal Design by EDN Design Ideabt Yishay Netzer, Consultant, Yuvalim, Israel
Broad Band 2Mhz Optical Fiber Receiver - if you need more sensitivity than the above circuit this circuit provides about ten times more gain. it too is designed around an inexpensive plastic optical fiber detector. . . Circuit by David Johnson P.E.-June, 2000
Broad Band 50Mhz Optical Fiber Receiver Version A - if the above circuit it still too slow, you can try this circuit. What it lacks in sensitivity it makes up for in speed. The circuit attaches a plastic fiber optic PIN photodiode assembly to a small box containing a small 3v battery and a standard . . . Hobby Circuit designed by David A. Johnson P.E.-June, 2000
Broken Solar Panels - As illustrated below, one way to salvage a large number of broken solar cells is to wire them in parallel, not in the more conventional series connection. Broken cells of various sizes and shapes are grouped together into panels of about one quarter to on . . . Hobby Circuit designed by David A. Johnson P.E.-January, 2012
Capacitance Touch Switch - A single 1.5v silver oxide button cell powers this complete touch activated switch circuit for 5 years. it features both a normally open and a normally closed set of solid state switch thermals. it also has an adjustable sensitivity, which can be set . . . Hobby Circuit designed by David Johnson P.E.-January, 2002
Cascode Light Receiver Circuit - This page provides a detailed explanation of how the modified cascode light receiver circuit operates. The cascode technique in conjunction with an inductive load provides very high current to voltage conversion as well as very high speed. . . Circuit by David Johnson P.E.-February, 2002
Cell Phone Solar Powered Charger - The simple circuit below regulates the voltage from a 6v solar panel to a fixed +5v. That voltage can be fed to any cell phone or USB connected portable device, to charge its battery. The circuit uses a Reg113-5 voltage regulator from Texas instruments . . . Hobby Circuit designed by Dave Johnson P.E.-January, 2011
Circuit Implements Photovoltaic-Module Simulator - 04/07/11 EDN Design Ideas: Use combinations of diodes to simulate photovoltaic cells. Electronics engineers often use photovoltaic-module simulators to test dc/dc-power converters, inverters, or MPPT (maximum-power-point-tracking) -control techniques. The use of these simulators lets you work in the laboratory with predefined photovoltaic conditions, thus avoiding the drawbacks of real photovoltaic modules. Various commercial simulators are available, but they are often expensive. Design by José M Blanes and Ausiŕs Garrigós, University Miguel Hernández, Elche, Spain
Circuit rejects Ambient light - 06/10/99 EDN Design Ideas: in some applications, you need to detect light signals in the presence of background light whose intensity can change by orders of magnitude. The circuit in Figure 1 uses an integrated photodiode/amplifier (OPT201) in conjunction with an integrator that drives two linear optocouplers (TiL300). Design by Massimo Gottardi, IRST, Trento, Italy
Clear Fluid Detector #2 - Using an ultra low power technique, this circuit detects when a clear fluid is inside a piece of clear plastic tubing. it can be used for fluid level control and monitoring. . . Circuit by Dave Johnson P.E.-October, 2005
Clear Fluid Monitor - An optical technique seemed like the best choice for this application. The simple circuit below works well but only when the light detector can be shielded from bright ambient light. A visible red LED launches light pulses through the side of the clear tubing and emerges at the opposite side. A phototransistor forms a light detector. The circuit takes advantage of the lens effect from any clear fluid inside the tubing. When there is only air in the tubing, the light scatters and spreads out quickly before it reaches the phototransistor . . . Circuit Solution by Dave Johnson P.E.-May, 2005
Color Film Makes Optical Filter - This isn’t an electronic circuit but the file shows the curve for an optical filter made from exposed color film. The material blocks most visible light but is very transparent to 880nM infrared light. Kodak 100ASA is exposed to "cool white" fluorescent light for about 5 seconds. . . Circuit by David A. Johnson P.E.-January, 1998
Color Sensor - Colour sensor is an interesting project for hobbyists. The circuit can sense eight colours, i. e. blue, green and red (primary colours) ; magenta, yellow and cyan (secondary colours) ; and black and white. The circuit is based on the fundamentals of optics and digital electronics. The object whose colour is required to be detectedadded 10/05) __
Color sensor - I built this color sensor to equip my third implementaton of brick sorter. Michael GasperI presents such a sensor in an article of Nuts and Volts magazine. His circuit is based on an input multiplexor. Three CdS photo-resistors, connected to this multiplexor, receive light through RGB colored filters (cleverly done with Lego transparent bricks). __ Designed by Philippe "Philo"Hurbain
Color sensor achieves high dynamic range with auto exposure - EDN Design Ideas: 03/04/2017 For machine vision and other applications, this circuit provide as consistent RGB sensing regardless of illumination level Design by Massimo Gottardi
Color Sensor for Robot - i'm developing a simple, active, color, object sensor for my robots based on three ultra-bright LEDs. An old-fashioned cadmium-sulfide sensor detects the brightness of the reflected red, green, and blue as each is turned on individually. __ Contact David Cook
Control Frequency Response & Noise In Broadband, Photodetector, Transimpedance Amplifier - EDN Design Ideas: 07/04/96 Converting the current output of a wideband photodetector to a voltage, minimizing noise, and achieving the desired frequency response can tax the patience of even an experienced designer. Careful selection and correct application of an op amp can often provide the best and most cost-effective solution. Choosing and properly applying a transimpedance amplifier for broadband photodetector applications involves understanding trade-offs. Manufacturers of components for wideband transimpedance applications often spec products only for selected detector diodes. These components can be prohibitively expensive for all but the narrowest applications. Design by Michael Steffes, Burr-Brown Corp
Control Room Light Intensity Digitally - 11-Nov-04 EDN Design Ideas: Many people favor different light and temperature settings for different rooms depending upon their mood or whether they are working or relaxing. The circuit in Figure 1 controls the intensity of the artificial light in a room and Design by Donal McNamara and Kieran Kelly Analog Devices, Limerick, Ireland
Convert Solar Powered Light to Flasher - The circuit converts an off-the-shelf solar powered LED path light from producing a steady state light to one that produces a flash. This circuit includes a tiny dual Schmitt trigger inverter IC which form the pulse generator and the daylight sensor circuit. The circuit produces a positive pulse, which feeds the constant current LED driver circuit.. . . Circuit by David A. Johnson P.E.-March, 2010
Dark Activated 12v Power Supply Switch - Using an inexpensive phototransistor, this circuit switches 12v to 24v power to a load, whenever the sun goes down . . . Hobby Circuit designed by David A. Johnson P.E.-July, 2006
Dark Activated Relay - This circuit switches a relay at dark via a Light Dependent Resistor or LDR for short. The applications are numerous. in my application, it switches on a light with an older type movement sensor and is mounted on the top corner of my workshop with the LDR __ Designed by Tony van Roon VA3AVR
Dark Activated Switch - This circuit will activate a relay when light falls to a preset level. Light level can be adjusted with VR1 and the relay contacts may be used to operate an external light or buzzer. __ Designed by Andy Collison
Dark Activated Switch-DAS1 10A/12V - The DAS1 is a combination manual switch and automatic dark-activated switch. it is designed to control up to 10 amps of 12V lights. A pair of high-intensity white LEDs are included in the circuit for built-in lighting. The circuit includes a low voltage disconnect circuit that prevents excessive battery discharge on battery operated systems. The DAS1 is ideal for solar powered lighting systems, it can also be used for line powered and automotive/marine applications. External 12V lights consisting of white LEDs, incandescent lamps and/or fluorescent lamps can be driven by the DAS1. __ Designed by G. Forrest Cook
Dark Detector - When the level of light on the photo-cell decreases, the 555 is activated. Photo-cells (Photo-resistors) have a wide range of specifications. Some cells go down to 100R in full sunlight while others only go down to 1k. Some have a HiGH resistance of between 1M and others are 10M in total darkness. For this circuit, the LOW resistance (the resistance in sunlight) is the critical value__ 555-Timer
Dark Detector - Dark Detector with NE555__
Dark Sensitive Switch - Dark Sensitive Switch is a simple project which operates a relay when the light falling on the LDR goes below a set point __ Designed by Rajkumar Sharma
Dark/Light Activated Relay - The potmeter adjust the trigger 'on' level. The diode in the diagram shows to be 1N914. This is ok if you have a light-duty relay, also the 1N914 is a signal diode so actually does not qualify. Use a 1N4001 (Tony van Roon's or better) instead. A couple of substitutes for the 2N2222 transistor are: NTE123A, ECG123A, PN100, etc __ Designed by Tony van Roon VA3AVR
Dark-activated 230V Lamp - Compact circuitry using small-size parts only; Can be wired in parallel to existing switches __ Contact Flavio Dellepiane, fladello @ tin.it
Dark-activated LED or Lamp Flasher - This circuit adopts the rather unusual Bowes/White emitter coupled multivibrator circuit. The oscillation frequency is about 1Hz and is set by C1 value. __ Contact Flavio Dellepiane, fladello @ tin.it
Dark-Activated Switch Needs Only Three Components - 23-Jul-09 EDN Design Ideas: Build a dark-activated switch with only a TRIAC, a photocell, and a resistor Design by Abel Raynus, Armitron International, Malden, MA
Dark-Detecting LED - Here's a simple problem: "How do you make an LED turn on when it gets dark?" You might call it the "nightlight problem, " but the same sort of question comes up in a lot of familiar situations-- emergency lights, street lights, silly computer keyboard backlights, and the list goes on. Solutions? Lots. The time-honored tradition is to use a circuit with a CdS photoresistor, sometimes called a photocell or LDR, for "light-dependent resistor. " __
DAS1 10A/12V Dark Activated Switch - The DAS1 is a combination manual switch and automatic dark-activated switch. it is designed to control up to 10 amps of 12V lights. A pair of high-intensity white LEDs are included in the circuit for built-in lighting. The circuit includes a low voltage disconnect circuit that prevents excessive battery discharge on battery operated systems. The DAS1 is ideal for solar powered lighting systems, it can also be used for line powered and automotive/marine applications. External 12V lights consisting of white LEDs, incandescent lamps and/or fluorescent lamps can be driven by the DAS1. __ Designed by G. Forrest Cook
Day/Night Switch-24vAC Powered - Many low voltage outdoor lighting systems use 24vac to power the devices. The low voltage is much safer to use outside than standard 120vac or 240vac power systems. The circuit below is designed to turn off power to outdoor lights during daylight and turn them back on at night. . . Circuit by David A. Johnson P.E.-December, 2010
Demodulator Makes Low Cost Optical Tracker - 06/18/98 EDN Design Ideas: (Several circuits here, scroll to find this one.) Demodulator makes low-cost optical trackerSteven Sarns, Kesta Technology inc, Wheat Ridge, CO A project required building a synchronous-demodulator circuit to track a line drawn on paper. The beauty of the synchronous-modulator/demodulator approach is its inherent noise rejection. The method rejects nearly all out-of-band noise, whether from internal drift or external illumination. Design by Steven Sarns, Kesta Technology Inc, Wheat Ridge, CO
Detect Clear Fluid - This circuit detects when a clear fluid is inside a piece of clear plastic tubing. it can be used for fluid level control and monitoring . . . Hobby Circuit designed by Dave Johnson P.E.-May, 2012
Detect Short Xenon Lamp Flashes - This circuit uses a small 2.5mm square photo diode in conjunction with a 100mH coil to detect the short light flashes from a xenon lamp. The coil makes the circuit immune to normal room lights. its 10mv sensitivity can detect light flashes from a range of over 100 feet. . . . Hobby Circuit designed by Dave Johnson P.E.-February, 2002
Detector Lightning - A VLF receiver tuned to 300 kHz designed to detect the crackle of approaching lightning. A bright lamp flashes in synchrony with the lightning bolts indicating the proximity and intensity of the storm. it has a superior RF section with a single resonance near 300kHz and plenty of sensitivity. The antenna is a telescopic antenna that extends to two or three feet __ Contact: Charles Wenzel of Wenzel Associates, Inc.
Detects Xenon Lamp Flash - This circuit has a very low standby current requirement yet has very high sensitivity toward the light flashes from a xenon lamp. When connected to a flip/flop it can serve as an on on/off Controller . . . Hobby Circuit designed by David Johnson P.E.-December, 2004
Digitally Control Room Light Intensity - 11-Nov-04 EDN Design Ideas: Many people favor different light and temperature settings for different rooms depending upon their mood or whether they are working or relaxing. The circuit in Figure 1 controls the intensity of the artificial light in a room and Design by Donal McNamara and Kieran Kelly, Analog Devices, Limerick, Ireland
DMM Measures Light Level - 08/15/96 EDN Design Ideas: The circuit in Figure 1 allows you to measure light using a regular digital voltmeter. The TSL230B (IC 1] is a programmable light-to-frequency converter whose output frequency is proportional to the light level. inputs S0 and S1 se Design by Yongping Xia, EBT Inc, Torrance, CA |
