Thread: Help! DIY Infra-red ?
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Old Feb 23, 2003, 01:37 PM
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Toronto (Don Mills), Canada
Joined Dec 2002
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Quote:
Originally posted by jberg

A good reason for choosing different parts would be a better ratio of sensitivity to proofness against different signals (ambient light, sunlight, fluorescent light, electrical noise). Any data about this?

Regards, Jochen
If you go to the Vishay site :
http://www.vishay.com/ir-receiver-modules/
at the bottom right under general information they have some further information on this. Unfortunately it seems to be specific to the standard sort of codes used in home electronic remotes, so I think we need to do some of our own testing. Your results are certainly useful data.

Based on my reading of these the choice of the TSOP1838 is a poor one. They want a 15ms gap at least every 90 msec for the AGC circuit to work correctly. Our frame rate is 16msec, so there is no gap for the AGC to recover. Our transmitted pulses must look a lot like AC noise to the IR rcvr. Perhaps we should be changing the encoding scheme with the PIC in the transmitter (and the rcvr decoding) to more closely match standard remote signals.
This is based on a fairly quick review of the application notes. I am going to try to find similar information for the Panasonic parts.

Pat MacKenzie
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