Brian Reed wrote:
>
> I found the egginc.com site but no details about this EG&G Vactec
> VTR24F1 IR emitter/detector.  Would like to know the electrical
> characteristics of the internal LED and photo transistor.  Any
> pointers to Vactec?  vactecinc.com doesn't look like the right co.


Brian, I have worked with many IR pairs from
VCRs, they are all very similar. Try running the
LED at 8mA, it should be about 1.1v Vf.
Connect the receiver diode anode to GND, and
it's cathode to +5v through a 2k2 resistor.
You can then connect the cathode directly to
a logic level input pin.

Changing the value of the 2k2 resistor will give
simple sensitivity adjust. This will give decent
on/off performance, if you want to use it for
analog value detection it gets more complex.
:o)
-Roman

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