Sensors /
Detectors: Light Detectors and Optical Sensors
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Light Detectors / Optical Sensors: #'s
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Last Updated on:
Monday, October 03, 2011 06:07 PM |
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Circuits designed by
Dave Johnson, P.E. : |
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LASER/LED LIGHT OUTPUT INTENSITY METER
This circuit uses a large 1cm X 1cm silicon PIN photo diode and a Transimpedance
amplifier to measure the light power output of infrared and visible LEDs and laser
diodes. It can be modified to produce almost any milliwatts to volts scale factor.
It can be connected to either a multi-meter or an oscilloscope.
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LIGHT DETECTORS WITH AMBIENT LIGHT 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 30KHz to 50KHz frequencies often used by TV and VCR remotes. I have not yet
tested the circuits.
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Links to electronic circuits, electronic schematics, designs for engineers,
hobbyists, students & inventors:
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Lamp Flasher - Simple photo-sensitive circuit 3V battery supply.... |
| Laser Light Detector, 10mhz to 20mhz -
This circuit was originally designed to detect laser light pulses for an optical Ethernet
communications system. It has good ambient light immunity.... [Designed by David A.
Johnson] |
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Laser Pointer Train Detector - This train detector makes use of hand held laser
pointer devices that are widely available to detect trains over long distances. [from Rob
Paisley's Model Train web site] |
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Laser/LED Light Output Intensity Meter - This circuit uses a large 1cm X 1cm
silicon PIN photo diode and a transimpedance amplifier to measure the light power output
of infrared and visible LEDs and laser diodes. It can be modified to produce almost any
milliwatts to volts scale factor. It can be connected to either a multi-meter or an
oscilloscope. …. [Designed by David A. Johnson] |
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Latching light detector is frugal with power and parts - 26-Sep-02 Issue of EDN
This idea demonstrates three uses for the humble LED. The circuit in Figure 1a forms a
simple light detector that latches and turns on an LED when the ambient light exceeds a
preset limit determined by potentiometer P1. LED D1 is both the indicator and the light
detector. All junction diodes exhibit some degree of photosensitivity.... [Design Idea by
Anthony Smith, Scitech, Biddenham, Bedfordshire, UK] |
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LDR light/dark activated relay Switch - (electronic circuit added 4/05)
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LED Light Dimmers uses only Two Lines - 03/21/02 EDN-Design IdeasThis circuit
provides32 steps of brightness control (from0 to100%]for a backlight or instrument panel,
using just two general-purpose-micr....PDF contains multiple circuits, scroll to find the
one of interest… [Design Idea by Jerry Wasinger,WallyWare Inc, Norcross, GA] |
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LED Photo Sensor Circuit - Here's a circuit that takes advantage of the
photo-voltaic voltage of an ordinary LED. The LED voltage is buffered by a junction FET
transistor and then applied to the inverting input of an op-amp with a gain of about 20.
This produces a change of about 5 volts at the output from darkness to bright light. The
100K potentiometer can be set so that the output is around 7 volts in darkness and falls
to about 2 volts in bright light.... [Bill Bowden] |
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LED Photodetector - Using the light-emitting diode as the photodetector (circuit
added 6/07) |
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LED senses and displays ambient-light intensity - 9-Nov-06 Issue of EDN
LED doubles as photosensor and visual indicator of ambient-light intensity.... [Design
Idea by Dhananjay V Gadre and Sheetal Vashist, ECE Division, Netaji Subhas Institute of
Technology, New Delhi, India; Edited by Brad Thompson and Fran Granville] |
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Light Activated Detector Circuit LM393/LM555 - This page shows three circuits
for using the 555 timer IC as a photocell controlled train detector. The
circuit is shown driving light emitting diodes but any load of less than 200 milliamps
could be used…..Circuit for model railroad trains…. [from Rob Paisley's Model Train web
site] |
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Light Activated Relay (Bowden) - This is same circuit as above with the addition
of a photo resistor to trigger the flip flop instead of a push button. The bias resistor
in series with photo resistor was chosen so that sufficient voltage is present at the base
of the 2N3904 to supply current to the circuit in ambient lighting conditions.... [Circuit
Designed by Bill Bowden] |
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Light Barrier Detector - .... |
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Light Dependent Resistor - Find out more about LDRs and their use in renewable
energy projects…. [REUK - Renewable Energy UK website] |
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Light Detector Circuit - Variable resistor R1 adjusts the light threshold at
which the circuit triggers. R1's value is chosen to match the photocells resistance
at darkness. The circuit uses a CMOS 4001 IC. Gate U1a acts as the trigger, U1b and c form
a latch. S1 resets the circuit. The output device may be a low power piezo buzzer.... Mick
Devine, UK] |
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Light Detectors With Amibient Light 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 30KHz to 50KHz frequencies often used
by TV and VCR remotes. I have not yet tested the circuits.... [Designed by David A.
Johnson] |
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