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Light Dependent Resistor Circuits
/ Photocell Circuits, Page 1
Light Dependent Circuits: # - CD - IJ - MN- Z Last Updated on:
Monday, October 03, 2011 06:07 PM
Circuits
Designed by Dave Johnson, P.E. :
24vac Powered Day/Night
Switch 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. The circuit uses
a phototransistor to detect daylight. I would suggest you use a
phototransistor which has a built in daylight filter. These are colored a deep
purple. The filter helps insure the circuit reacts only to sunlight....
Links to electronic circuits, electronic schematics, designs
for engineers, hobbyists, students & inventors:
24vac Powered Day/Night Switch
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. The circuit uses a phototransistor
to detect daylight. I would suggest you use a phototransistor
which has a built in daylight filter. These are colored a deep
purple. The filter helps insure the circuit reacts only to
sunlight.....[Designed by David A. Johnson]
4 & 8 Infrared-Proximity Detectors (TSOP4830) - In this
circuit the TSOP4830 is used as a sensitive infrared detector that
does not require shielding from room lighting. The detector will
work under almost any lighting condition from complete darkness to
full sunlight….scroll down for this one…. [from Rob Paisley's Model
Train web site]
4 in 1 Burglar Alarm - In this circuit, the alarm will be switched on
under the following four different conditions: 1. When light falls on LDR1 (at
the entry to the premises). 2. When light falling on LDR2 is obstructed. 3. When
door switches are opened or a wire is broken. 4. When a handle is touched. The
light dependent resistor LDR1 should be placed in darkness near the door lock or
handle etc. If an intruder flashes his torch..... [Radioland.nt.au]
8 Photo-Detector Circuit - There are two versions of the "8
Photo-Detector" circuitboard. Circuitboards and parts are available for both
versions of this circuit..... [from Rob Paisley's Model Train web site]
Across The Track Infrared Detectors - This page presents information
on infrared 'Across The Track' train detection circuits. The circuits are
designed around the LM339 comparator chip and can use a wide assortment of
matched infrared emitter / detector pairs. [from Rob Paisley's Model Train web
site]
Basic Infrared Proximity Detector - The circuits on this page are for
an Infrared Proximity Detector using the Vishay Electronics TSOP4830 "IR
Receiver Modules for Remote Control Systems"….Scroll down to view all the
circuits…. [from Rob Paisley's Model Train web site]
Block Occupancy Detector Helper Circuit information - This circuit
would be used to hold a BLOCK OCCUPIED condition as a train passes out of the
block even if the normal detector is not sensing a train. [from Rob Paisley's
Model Train web site]
Circuit rejects ambient light - 06/10/99 EDN-Design Ideas EDN is
migrating links. This link is not verified. Search the "title" + "EDN" for
new link.
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 detected.....added 10/05)
