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Detectors: Light Detectors and Optical Sensors
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Light Detectors / Optical Sensors: #-C
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Last Updated on:
Thursday, November 30, 2017 04:30 PM |
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Circuits designed by
Dave Johnson, P.E. : |
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Light
Intensity Monitor
For an on-going consulting project, I had to determine the light output decay time
of different fluorescent lamps. I wanted to know how fast the light from a lamp
dropped to a low level, after current was interrupted in the lamp. I used a high
voltage transistor circuit to drive the lamps under test and used the hobby circuit
below to measure the decay time. the hobby circuit was a simple PIN photo diode
connected....
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[_OLD-ads-dont_upload/OLD I-ADS from web/ad-special.htm] |
- Light to
Frequency Converter
This circuit uses a CMOS version of the classic 555 timer, to form a light intensity
to frequency converter. A small PIN photo diode is used as the light detector.
The pulses produced are short, so in some applications you may want to stretch them
or feed them through a flip/flop to produce a square wave signal. Although the
circuit shown is designed for a 5v supply, it could operate from almost any voltage
from 3v to 15v.
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LIGHT RECEIVER WORKS FROM 1KHz TO OVER 70MHz
This circuit uses one tiny C-MOS inverter IC to form a modulated light receiver with
a very fast response. It is designed around a PIN photo diode that is packaged for
use with plastic optical fibers. It can be used as an optical fiber receiver. By
using the open end of the optical fiber it can "sniff" out any modulated light
signals.
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Low power 100KHz Light Receiver
By starving a high speed logic inverter for current, this circuit can produce a
sensitive 100KHz light receiver circuit, which is immune to ambient light, but only
drawing 100 microamps from a 3 volt supply.
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Links to electronic circuits, electronic schematics, designs for engineers,
hobbyists, students & inventors:
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Light direction sensor - (schematic added 02/09) |
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Light Intensity Monitor - For an on-going consulting project, I had to determine
the light output decay time of different fluorescent lamps. I wanted to know how fast the
light from a lamp dropped to a low level, after current was interrupted in the lamp. I
used a high voltage transistor circuit to drive the lamps under test and used the hobby
circuit below to measure the decay time. the hobby circuit was a simple PIN photo diode
connected.... [Hobby Corner Circuit by Dave Johnson] |
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[_OLD-ads-dont_upload/OLD I-ADS from web/ad-djandassoc.htm] |
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Light Pollution Meter - (Circuit design added 8/03) |
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Light Receiver works from 1kHz to over 70mhz - This circuit uses one tiny C-MOS
inverter IC to form a modulated light receiver with a very fast response. It is designed
around a PIN photo diode that is packaged for use with plastic optical fibers. It can be
used as an optical fiber receiver. By using the open end of the optical fiber it can
"sniff" out any modulated light signals.... [Designed by David A. Johnson] |
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Light Sensing RF Transmitter - Photo sensor is placed in series with a
resistor…. [Tony van Roon's circuit] |
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Light Sensitive Alarm Circuit - The circuit detects a sudden shadow falling on
the light-sensor and sounds the bleeper when this happens. The circuit will not respond to
gradual changes in brightness to avoid false alarms. The bleeper sounds for only a short
time to prevent the battery running flat. Normal lighting can be used, but the circuit
will work best if a beam of light ….... |
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Light Sensor Adapter for Oscilloscope - (electronic circuit added 4/05)
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Light Sensor With Hysteresis - It is quite a simple circuit but rather more
effective than the one using the 741. It uses a simple comparator LM311 as the master
piece. This comparator is powered from a +12V DC supply and does not require
negative supply to work efficiently. The feedback given to the comparator provides some
hysteresis and the potentiometer allows to adjust the sensitivity of the detector for
darkness. I am quite sure you could inverse R1 and R2 positions to inverse the action of
the detector but I haven't tried it! …. [By Frank Rivard] |
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Light Sensor-741 Based - The circuit as shown act as a light sensor. Under
normal conditions the resistance of the LDR is high, keeping pin 2 low. When light falls
onto the LDR the resistance drops to a couple hundred ohms and triggers pin 2 high which
biases the base of Q1 via pin 6 and R4 and in turn activates the relay.…. [Tony van Roon's
circuit] |
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Light to Frequency Converter - This circuit uses a CMOS version of the classic
555 timer, to form a light intensity to frequency converter. A small PIN photo diode
is used as the light detector. The pulses produced are short, so in some
applications you may want to stretch them or feed them through a flip/flop to produce a
square wave signal. Although the circuit shown is designed for a 5v supply, it could
operate from almost any voltage from 3v to 15v. …. [Hobby Corner Circuit by Dave Johnson] |
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Light/Dark Detector - This handy little circuit can tell the difference between
darkness and light, making it very useful for switching on and off signs, porch lights or
other things when it gets dark or light…. [Aaron Cake's design] |
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Light-Sensitive Alarm - The circuit detects a sudden shadow falling on a
light-sensor and sounds a bleeper for a short time (adjustable). Normal lighting can be
used, but the circuit will work best if a beam of light is arranged to fall on the
light-sensor. Breaking this beam will then cause the bleeper to sound.... [Designed by
John Hewes] |
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Line Powered Xenon Flash Transmitter - This line powered xenon flash circuit
drives a small camera type flash tube. It has an optical isolator to allow the flash to be
safely triggered from some remote device. A flash rate of 2Hz is possible with the
circuit. …. [Designed by David A. Johnson] |
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LM741 Light Dark Sensor Circuit - Build a light/dark sensing circuit to
automatically turn on/off lights and other devices…. [REUK - Renewable Energy UK website] |
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Low power 100kHz Light Receiver - By starving a high speed logic inverter for
current, this circuit can produce a sensitive 100KHz light receiver circuit, which is
immune to ambient light, but only drawing 100 microamps from a 3 volt supply.... [Designed
by David A. Johnson] |
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LX1970 Visible Light Sensor AN-28 - Application Note 28 from Microsem....[App
Note] |
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