741 Based Light Sensor: CdS photocell used for
light/dark controlled relay |
Basic Infrared Light Train Detection:
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Battery Powered Sensor Detects Dangerous U Volt
Radiation: 12/08/94 EDN-Design Ideas
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Block Occupancy Detector Helper:
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Dark / Light Activated Relay:
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Dark Activated Switch or Porch Light Switch:
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Darkness monitor : |
Day and Night Infrared Detection:
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Demodulator Makes Low Cost Optical Tracker:
06/18/98 EDN-Design Ideas |
Infrared to Light Converter: This circuit
converts infrared light into sound. Modulated
Infrared light, like that ROM remote controls,
Infrared received by the phototransistor and is
amplified by the LM386 IC. |
Laser Pointer Train Detector: |
Latching light detector is frugal with power and
parts: 09/26/2002 EDN - Design Ideas / 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. |
Light / Dark Detector: |
Light Detector #1: |
Light Detector #2: |
Light Direction Sensor: |
Light
Intensity Sensor: Logarithmic amplifier uses the
log caracteristic of PN (diode, transistor) to
implement logarithmic function. The second
transistor is used as refference and with the PTK
resistor minimizes the dT/dV coeficient.
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Light Pollution Meter : LED brightness control
circuit and a multimeter to compare light levels to
LED level. |
Light Sensing RF Transmitter:
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Light Sensor Adapter for Oscilloscope:
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Light Sensor With Hysteresis:
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LIGHT/DARK ACTIVATED RELAY: This is actually two
circuits a light activated relay being the first and
a dark activated relay being the second, once again
all components and values are displayed in the gif
image. |
Matched Diode Pair Improves Performance Of Linear
Optical Sensor : 05/27/02 Electronic Design -
Ideas for Design / Hand-marked cards for
applications like voting machines and meter readers
often have dark marks, light marks, erasures, or
dirt. Digital systems can't distinguish between an
intended mark, dirt, or erasure because they have a
single preset threshold.... |
Optical sensor needs no tweaking: 06/13/2002
EDN - Design Ideas / The transfer gain of optical
sensors spans a 16-to-1 ratio because of variations
in the LED, phototransistor, ambient temperature,
and optical path. The wide transfer-gain variation
complicates output-resistor selection in dc-coupled
circuits. You must size the output resistor to
prevent high transfer gains from causing
output-stage saturation, but low transfer gains
yield low output-voltage sw.... |
Photodetector Sorts Objects: 03/04/99 EDN-Design
Ideas / PDF contains multiple circuits - scroll to
find this circuit. |
Programmable Light Activated Relay:
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Pulsed Sensor Extends Battery Life: 01/01/98 EDN-Design
Ideas |
RF Transmitter, Light Sensing:
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Solar sun tracker : |
Two LEDs Perform Rudimentary Spectral Analysis:
09/01/94 EDN-Design Ideas |
U Volt Sensitive Photodetector: |
Using The LM555 Timer With Photocell Detectors:
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Visible Light Photo Detector Circuits (E+F):
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