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Light Dependent Resistor Circuits / Photocell Circuits
Light Dependent Circuits:  #'s - D      E - L      M- Z

 

Last Updated: October 24, 2017 02:55 PM

Circuits Designed by Dave Johnson, P.E. :

AIR Transparency Monitor-Pg2This is of the receiver circuit AIR TRANSPARENCY MONITOR, XENON FLASH RECEIVER. . . Circuit by David Johnson P.E.-June, 2000

Ambient Light Dectector with CompensationThese circuits were taken from a few application notes on infrared remote control devices.  They use a current compensation method to separate the modulated light pulses from ambient light.  They appear to have limited bandwidth and may only work at the 30K . . . Hobby Circuit designed by David Johnson P.E.-July, 2000

Amplifier for a Xenon Lamp Flash Detector  - 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. . . Circuit by David Johnson P.E.-February, 2002

Broad Band 2Mhz Optical Fiber ReceiverIf 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 AIf 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 PanelsAs 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 Johnson P.E.-January, 2012

Cascode Light Receiver CircuitThis 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 ChargerThe 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

Clear Fluid Detector #2Using 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

Color Film Makes Optical FilterThis 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

Convert Solar Powered Light to FlasherThe 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 SwitchUsing 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

Day/Night Switch-24vAC PoweredMany 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

Detect Clear FluidThis 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 FlashesThis 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

Detects Xenon Lamp FlashThis 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


Links to electronic circuits, electronic schematics, designs for engineers, hobbyists, students & inventors:

AIR Transparency Monitor-Pg2 -  This is of the receiver circuit AIR TRANSPARENCY MONITOR, XENON FLASH RECEIVER. . . Circuit by David Johnson P.E.-June, 2000

Ambient Light Dectector with Compensation -  These circuits were taken from a few application notes on infrared remote control devices.  They use a current compensation method to separate the modulated light pulses from ambient light.  They appear to have limited bandwidth and may only work at the 30K . . . Hobby Circuit designed by David Johnson P.E.-July, 2000

Amplifier for a Xenon Lamp Flash Detector  -  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. . . Circuit by David Johnson P.E.-February, 2002

Automatic Darkness-Controlled Lighting SystE - M -  Make tubelights automatically switch on at night and switch off in daytime using this automatic control system.  Automatic darkness-controlled lighting system means that whenever there is darkness, light source like bulb...__ Electronics Projects for You

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 Johnson P.E.-January, 2012

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.   __ Circuit 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  (TI - L300) .    __ Circuit 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

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 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 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  __ Circuit 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 __ Circuit 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

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  __ Circuit Design by Donal McNamara and Kieran Kelly, Analog Devices, Limerick, Ireland

   <<<         This is the last page of #'sD

Light Dependent Circuits:  #'s - D      E - L      M- Z

 


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