8ea ( Matched Pair ) Infrared LED Photo Emitter & IR Photo Detector Receiver NOS

Description

Infrared IR Matched Assembly
PhotoEmitter / PhotoDetector Pair, T-1 Size
( Purchase is for 8 of the Units Shown )
End the hassle of trying to find "Matched
Pairs" of Detectors and Emitters that
operate at the same wavelength. These
pairs were designed with that in mind for
maximum efficiency and reliability. They
were made for the automobile industry so
reliability was an important requirement.
Compare these to others you find on eBay,
then decide which ones you feel you can
trust in your own project.
Please refer to the additional photos
I've provided above. They show a
couple simple circuits you may be
able to apply or modify to suit the
needs of your application.
Application ideas:
Make a Tester for your IR Remote Controls
Detect whether Doors are Open or Closed
Detect when windows have been opened.
Detect drawers and cabinets that have been opened.
Detect when a piece of equipment is properly positioned
Detect passing items on an assembly line and increment a counter
I've provided lots of additional information below on this
Photo LED IR Pair.
If you prefer, you can unsolder the
Emitter and Detector from each other and
place them across from one another to get
greater detection range.
However, should you decide to use them
as they are with the aid of a reflective
surface, that's ok too. The reflective
surface will just have to be in close
proximity to the semiconductor pair. When
the IR Photo Detector is receiving light
from the Photo Emitter, it's resistance
changes becoming about one tenth of it's
dark resistance. This makes detecting the
presence of a reflected surface very
easy. It just requires a simple voltage
comparator to do the monitoring. In fact,
a 555 timer so wired to use it's internal
comparators would probably do the job very
nicely, and it's output would be capable
of activating a relay, a light, an alarm,
or even a High-Power Solid State Relay.
The optimum distance between the
Emitter/Detector pair and the reflective
surface is about 1/4 inch. However, that
distance can be increased by careful
selection of the photo detector series
resistor and/or by setting the comparator
trigger point to a lower voltage.
I've included a circuit diagram that shows
a sample detection circuit.
This is a far better way to detect the
presence of a near by moving object than
using mechanical switches that can get
out of adjustment or wear out. There is
nothing mechanical to wear out with this
technology.
More Info on building a Tester for IR
Remote Controls: You can use the same
basic comparator circuit shown in the 2nd
photo; however, you might prefer to have
the Green LED light only when a signal is
being received from the IR Remote Control
being tested. In such case, you will need
to connect the Green LED between the 3.3k
ohm resistor and the minus supply lead,
with the Green LED anode connected to the
3.3k ohm resistor.
I have tried this basic circuit with a
half dozen different IR remote controls
I have, and it detected all of them. The
Data Stream sent by some of the remotes is
quite fast though, so you might have
to watch the Green LED closely on some
remotes. Of course, you could easily
remedy that little inconvenience by
connecting a 555 Timer capacitively
coupled to the output of the comparator
in Monostable Mode. That way when the 555
timer detects a pulse at the comparator
output, the 555 timer can light a 2nd LED
for whatever length of time you desire
(like perhaps a second or two).
Two great books for the home electronics
hobbyist that will provide you with lots
of great "Know How" on how to do these
kind of things (and much more) are Don
Lancaster's "TTL Cookbook" and his "CMOS
Cookbook".
Sorry, I don't have any hard specs on this
assembly, but I can tell you that it
was intended for use in automotive
applications. So the maximum voltage
rating is probably around 25 volts. The
Photo LEDs are T1 size (3 mm Diameter).
The Total width of the Photo LED pair is
12 mm and the total height including lead
length is 17 mm.
Application ideas:
Detecting when the big garage door is open.
Detecting when home windows and  doors have been opened.
Detecting when drawers and cabinets have been opened.
Detecting when a piece of equipment is properly positioned (or is out of position)
Detect passing items on an assembly line and increment a counter
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