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Last Updated
03/31/2019
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Detailed entries for one subject from the INDEX TO HOW TO DO IT INFORMATION. |
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PHOTOELECTRIC DEVICE sa LIGHT BEAM COMMUNICATION sa LIGHT METER sa OPTOELECTRONIC DEVICE sa PHOTOELECTRIC LIGHT CONTROL sa PHOTOMETRY & RADIOMETRY sa PHOTOVOLTAIC DEVICE x ELECTRIC EYE x LIGHT SENSOR x PHOTOCELL xx ELECTRONICS xx LIGHT METER xx REMOTE CONTROL xx SWITCH -- ELECTRONIC xx TRANSDUCER A computer controlled stepper motor light scanner. A scanning sensor capable of detecting both infrared and visible light can be used as part of an alarm system. It will detect and then track the source of the light. May have application in light-seeking robots. Adjustable threshold temperature alarm and light-detection alarm circuits. Wireless remote control circuit uses a beam of light to control model trains or boats or other electrical devices. Circuits for a (1) proximity detector and (2) light sensor incorporate a light-to-voltage converter chip. Light alarm unit produces a noticable audio tone when the unit's photocell is subjected to a reasonably high level of light. Circuit can be modified to sound alarm if light level falls or decreases below a certain level. Photoelectric switch turns television sound off and on. Theory and simple projects using photocells, both photoconductive and photovoltaic types. Photosensitive devices. Learn to use photoconductive cells, photodiodes, and phototransistors in practical light-controlled circuits. This photocell-activated signal device with an audio output can be used to monitor signal lights on the front of electronic equipment when you are behind the equipment making adjustments, thus eliminating the need for a mirror or a second person. Description of how a photocell works and typical applications. Photoelectric alarm monitors ambient light in a photographic darkroom. When light rises to an unsafe level the alarm goes off, sounding a bell or cutting electrical power. Can be modified for other purposes (burglar, fire, freezing, ...). Cyclops. Circuit using the Optolinear IC can be used in a burglar alarm, automatic doorbell, target for a light gun, etc. Remote control will kill the TV sound with a blink of a flashlight. Garage parking aid circuit. Wall-mounted photocells detect your automobile headlights and tell you when your car is centered in the available space. Photo alarm circuit causes a relay to be tripped as light levels rise or fall. Circuit enables you to know when a lamp goes out for any reason, including a burn-out or a fuse blow. Electronic wake-up call is turned on whenever light is detected. Use as an alarm clock or a novelty gadget. Light detector circuit is used to trip a relay to open a garage door, turn on an appliance, etc. Light-sensitive alarm circuit (annunciator) sounds an audio alert whenever someone enters a door. Automate your porch, driveway, or outdoor lights without generating radio-frequency interference (RFI). This photoelectric switch allows for trimming the triggering light intensity, and can power multiple devices. Electronic Tattletale monitoring circuit keeps a constant vigil on any pilot or indicator lamp. An alarms sounds whenever the lamp turns on-or-off. Light-triggered circuit. Use as a light sensor or as a simple continuty tester. Using op-amp comparator circuit chips to detect and measure real-world conditions. Circuits for monitoring temperature, light level, voltage, etc. Photocell detector circuit costs less than $1. Circuit for a photocell switch that will shut off TV commercials using the beam of a flashlight. Sun-powered alarm. By positioning a photocell at the bottom of a long, dark tube you can cause the sun to activate the alarm only when it is exactly over the opening of the tube. Est. cost: under $11. Totally passive intruder alarm measures the reflected light from any constant illumination source as it reflected off a black surface. Should the light level go up, an alarm is sounded. Est. cost: Under $9. Circuit to turn small motors on and off in response to a light beam. Use to control model trains or toys. Est. cost: under $9. How to get started in electronics. Part 1: Inside semiconductors. Looks at the diode, transistor, SCRs, LEDs, light detectors, etc. Build this wireless remote pause control for your VCR. Use a flashlight to activate and shut off from anywhere in a typical room. Est. cost: $10. Experimenting with the analog comparator, a special circuit incorporating the operational amplifier. Circuits include (1) an adjustable light-dark detector, (2) adjustable-threshold temperature-controlled relay, (3) a sine- to square-wave converter, and (4) a peak-voltage detector. A pilot-lamp beeper. Audibly alerts you when an electrical appliance with a pilot lamp is left on. Powered by a 9-volt battery. Requires no connection to the pilot lamp circuit. Tips on using self-focusing photodiodes. Possible uses include barcode reading, document scanning, etc. Teleguard. Part 3. Solid-state sensing modules. Low-cost circuits you build to enhance the operation of the Teleguard security system. Includes light-activated sensors, temperature-sensing module, and fluid-detecting module. Audio amplifier experiments. Includes construction of a simple audio amplifier, underwater hydrophone, light-sensor/amplifier combinations, and a basic "photophone" system. Surface-mount-device circuits: A design and construction guide. Projects include using SMCs (surface-mountable components) to produce a subminiature LED tone transmitter, A/D converter LED bargraph or metering circuit, and light-sensitive oscillator (probe). Photo sensor operating-status indicator. Use a Darlington phototransistor to monitor a remote LED or lamp. The on-off status is displayed on this monitor by means of an LED and/or an audible signal. Useful when troubleshooting a variety of interconnected devices, each with its own set of status lights. How to detect ultraviolet, visible and infrared radiation. Part 1. Experimenting with thermister, thermopile and pyroelectric detectors. How to detect ultraviolet, visible and infrared radiation. Part 2. Photodetectors, photoemissive detectors, etc. Applications of photocells. Photocell circuits. (1) One-transistor photocell circuit. (2) Two-transistor photocell circuit. Very sensitive electronic relay for use in alarms, controls, etc. Bistable photoresistive switch is activated by a flashlight. One flash of light turns it on and it remains on until another flash turns it off. Photocell demonstrator. Relays operated by photo-cell driven amplifiers, apply and remove power from the motor. Switch can be operated by a light beam from remote locations of up to 30 feet. The in-out annunciator can detect which way the object was moving which broke the beam of light. Est. cost: $20. Circuit designed to switch 240 watts with a change in light levels. Used to operate an aquarium heater. Headlight-operated garage door or light switch. Simple circuit is powered by 9-volt battery. Trips relay to operate door or light. Sensitivity can be adjusted. Build a light probe. This electronic device will help a blind person locate a source of light such as pilot lights, the sun or even wave forms on an oscilloscope. Produces an audio signal with frequency proportional to the amount of light striking photocell. TV commercial killer. Flashlight beam shuts off unwanted TV sound using this circuit. Solid-state photocells for hobbyists. Part 1. What goes on inside light-sensitive semiconductors. More circuits using the 555 IC timer include (1) tone generator, (2) code practice oscillator, (3) CW monitor and (4) electric-eye annunciator. Solid-state photocells for hobbyists. Part 2. How light-sensitive semiconductors are used in practical circuits. A look at the RCA CA3062 Photo Detector and Power Amplifier IC. Some suggested circuits and tips on using the IC in light-activated controls, alarms, door openers, etc. Low-cost remote control of appliances and lights. A flashlight beam turns a circuit on and off. Will handle up to 450 watts. Est. cost: $19. Light-controlled oscillator circuit provides an audible signal which changes in pitch with different light levels. Might be used as a "seeing aid" for the blind. Simple circuit cuts off TV sound when you shine a flashlight on a sensor. Turn up to 350 watts of ac power on-or-off in response to light level using this photocell, transistor-diode ac power control system. Three sensors provide for a kind of "combination lock" to prevent children from activating dangerous electrical appliances. Sensors are concealed in artificial flowers in this example. Photoelectric sensor. An in/out detection system counts events (up and down) and can be used to control lights, appliances, etc. Can count up to 9, 99, 999, or higher. Photo switch can be activated by a flashlight. Uses an op amp in the circuit. Circuit for a remote light-operated switch. Photoelectric switch turns electrical equipment on-or-off when a flashlight beam hits the photocell. The photoresistor. How it works and some typical circuits including a light meter, analog/digital converter and light-activated relay. Circuit for an inexpensive electric eye. Est. cost: $3 Build a field disturbance sensor for security. Alarm device detects light changes within its field of view. Eavesdropping on light. A look at detectors and amplifiers for monitoring modulated light sources. Circuit for ambient light compensation for a photosensor circuit. Simple circuit can function as either a light detector or a dark detector and sound alarm when appropriate. Build an optical motion detector alarm that detects motion through light changes. Use as a burglar alarm, plus a smoke and fire detector. Wireless switch uses a beam of infrared light to shut off television commercials (video and/or sound) for a preset period (30 or 60 seconds). Est. cost: $69. Open-humidor alarm. Circuit sounds an alarm if exposed to light for more than a few seconds. Use to remind someone to replace the top on a humidor. Build a "smart" light controller for a greenhouse. Turns grow lights on and off as needed, depending upon the amount of sunlight being received. An appliance "off" reminder. Low-cost project uses a phototransistor to produce an audible alert whenever an appliance indicator light goes off. Two circuits use a 7490 TTL decade counter and photocell to count people coming and going through a door. TV commercial zapper is connected in series with the speaker wire. A light beam interrupts the signal to the speaker. Window generator circuit can be used as a light or dark detection circuit, temperature monitor, rain detector, etc. Ultra-simple remote-activated AC control circuit is triggered by a brief flash from an ordinary flashlight. Digital electronics course. Light-controlled monostable applications. Combining the basic monostable multivibrator with a light-controlled comparator. How to salvage large metal-encased transistors. You might be able to repair the transistor or use its light-sensitive properties in a photoelectric device. Electronic aids for the blind. (1) Liquid-level indicator for a cup or glass. (2) Light probe turns light into sound. Simple circuit turns light into sound. The 555 oscillator/timer chip forms the heart of a circuit which turns on a buzzer when light strikes a photoresistor. Circuit sounds an alarm for 30 seconds if it detects any light for 15 seconds. Can be used to detect an open refrigerator door. Light detector circuit is designed to help visually-impaired persons pinpoint light sources. Sensors made simple. The construction, characteristics and operation of commercially available sensors such as mechanical switches, magnetic switches, photocells, phototransistors, and optocouplers. Using a single special-purpose IC (the ULN2429A fluid detector) in as many applications as possible. (1) Low-level liquid level detector. (2) High-level liquid level detector. (3) Touch-activated switch. (4) Proximity sensor. (5) Ultrasonic pest repeller. (6) Variable square-wave generator. (7) Code-practice oscillator. (8) Alarm circuit. (9) Light beam circuit (LED-emitter / phototransistor-sensor circuit). Light detector monitors a portion of a security video-camera monitor screen for any change in light levels. Two circuits shown. Build the Pathfinder, a navigational aid for the visually impaired. An easy-to-build, light-sensing circuit that can be used to sweep an area to locate the direction of light sources. Useful for finding windows and doors. Electronic sensors. Circuits for a group of 5 non-moving, non-mechanical replacement sensors that are IR light operated. (1) See-through sensor. (2) Light-block sensor. (3) PLC interface. (4) Reversed PLC interface. (5) Reflective sensor. Simple op-amp application circuits. (1) Fixed voltage reference. (2) Light-operated sensor. (3) Alarm sensor. (4) Voltage-level sensor. (5) Peak-voltage detector and hold. (6) DC motor driver and reverser. (7) Simple timer circuit to delay relay operation for up to 30 seconds. Audible light comparator circuit uses a unique infrared light-to-frequency converter IC to measure any difference in light falling upon a photodiode. Three light-interruption detector circuits are designed to detect when an opaque object passes between the IR source and an IR detector. Phototransistor basics. An introduction to photosensitive devices available to the electronic designer. Build a light activated switch. Electric eye can serve as burglar alarm and automatic doorbell. Est. cost: $10. Electric-eye alarm is so sensitive it can be triggered by a shadow. Very sensitive electric eye does not require the separate ligh-beam source of conventional electric eyes. Can use only AC powered light source within 12 or 15 feet. Has an adjustable sensitivity control. Flue bug. Low-cost electronic device warns you to close the damper on a chimney as soon as the fireplace fire has gone out. A photo-Darlington transistor is used to sense light and radiated energy from the fireplace. When no longer present, a light will start to blink telling you to close the damper. Est. cost: $10. Build this light sensitive security alert. Nearby movement will cause diffused shadows which are picked up by a photodiode and trigger the alarm. Est. cost: $25. Sensing circuits. Three methods for sensing when a circuit is active. Looks at light, coil, and series dropping resistor sensing techniques. Light-sensitive timing circuit. Use a change in light levels to turn on a circuit. Then a timer will turn it off after a predetermined time lapse. Robotics. Simple solid-state vision systems. Part 1. Constructing a simple photocell-based vision sensor. Robotics. Simple solid-state vision systems. Part 2. Connecting a simple photocell-based vision sensor to a microcomputer. Photocell switch turns TV commercials off and on in response to a signal from a flashlight. Est. cost: $12. Chanticleer, the electronic rooster. Device senses the sunrise and sets off an audible alarm. A useful alarm clock for those people who want to get up at sunrise. Est. cost: $15. Electronic alarm signals a change in light levels. Can be used to signal the coming of sunrise or the dimming of the light of a campfire, among other uses. Flash switch. Turn television sound off and on by shining a flashlight on this light sensitive switch. Build your own Cyclops, a light intensity monitor that can be used as an intrusion detector or as part of an electronic rifle range. Printed circuit board template included. Ptyalin experiments show basic enzyme action. Includes a photoelectric device to measure activity of enzymes. Photoelectric temperature control device uses light bulb, thermometer and photocell. Build an electronic neuron. This hard-wired neural network tracks the sun by keeping two photosensors equally lit. | |||||||||
Copyright © by Norman Lathrop Enterprises. All Rights Reserved. No part of this publication may be reproduced, stored in a retrieval system or transmitted, in any form or by any means (electronic, mechanical, print photocopying, recording or otherwise) without the prior expressed permission of Norman Lathrop Enterprises, except as permitted by law. |
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