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IR vs IRDA

Posted: Mon May 29, 2006 10:46 am
by ElizabethD
I know that the wavelength of IRDA signals is different from IR signals we talk about here by about 10-12%. Still, is it possible for IR signal to make IRDA port on a computer respond, especially if they use (guessing here) the same NEC1 protocol?
By 'respond' I don't mean anything reliable or designed, but rather interference, enough to cause the PC do goofy things when a remote for, say, TV is used.

Re: IR vs IRDA

Posted: Mon May 29, 2006 11:00 am
by johnsfine
ElizabethD wrote:I know that the wavelength of IRDA signals is different from IR signals we talk about here by about 10-12%.
I didn't know that, but even if it's true it must not create a significant incompatibility. IrDA hardware can send and receiver remote control signals.
ElizabethD wrote:Still, is it possible for IR signal to make IRDA port on a computer respond, especially if they use (guessing here) the same NEC1 protocol?
IrDA is a protocol as well as a set of hardware. That protocol is nothing like NEC1.
ElizabethD wrote:By 'respond' I don't mean anything reliable or designed, but rather interference, enough to cause the PC do goofy things when a remote for, say, TV is used.
Sounds unlikely. I don't know for sure that the IrDA receive hardware and software in a PC aren't so horribly misdesigned that they mistake a totally dissimilar signal for an IrDA signal. But NEC1 and IrDA are both common enough, such an error should have been found and fixed quickly.

I can't tell whether you are trying to understand/avoid a problem or whether you're trying to generate a response.

A JP1 remote can generate IrDA signals, so with decent documentation on what IrDA signals you want to send (which I don't know where to get) you could send those signals.

Posted: Mon May 29, 2006 12:54 pm
by ElizabethD
johnsfine wrote:I can't tell whether you are trying to understand/avoid a problem or whether you're trying to generate a response.
The ONLY reason for this post is to understand just a bit and to see whether a conflict is conceivable. I saw a post someplace about a claim that a TV remote affects a PC and wondered whether it's likely. There was no details there.
The wavelength info is from Mike
https://www.hifi-remote.com/forums/viewtopic.php?t=2921
The extent of my knowledge about IRDA is from the handful of posts I found here after search.
I made up the NEC1 idea based on some lirc file I found for a Packard Bell computer remote and a mention of Akai TV.
http://lirc.sourceforge.net/remotes/pac ... ckard_bell
Just goofin' around :) I have no idea what I'm looking at and it's too hot to do yardwork or clean the house.

Posted: Mon May 29, 2006 5:50 pm
by Mark Pierson
ElizabethD wrote:it's too hot to do yardwork or clean the house.
The grass (or is it weeds) is over a foot tall, the sink is full of dishes, and the family has no clean clothes... but Liz is sitting there controlling all her IR devices with her trusty JP1 remote! :eek:

You go, girl! 8)

Posted: Mon May 29, 2006 7:48 pm
by ElizabethD
Mark Pierson wrote:The grass (or is it weeds) is over a foot tall
Priorities, Mark! Weeds take on a whole different meaning when you think of them as wildflowers :D

I don't expect John to answer any more, there's almost no need. But do you read his answer as 'interference is unlikely but can occur'?

Posted: Tue May 30, 2006 1:33 am
by underquark
Remember, if you've got weeds then you've got (or had) sunshine and that should be considered as a possible source of interference. Although IrDA is meant to be fairly tolerant in the visible spectrum, bright light can affect mice or other tracking devices.