Subject:
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Re: ir tower -> consumer electronics
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Newsgroups:
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lugnet.robotics
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Date:
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Fri, 28 Apr 2000 05:48:36 GMT
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Original-From:
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Johan Pollet <johan.pollet@/StopSpammers/alcatel.be>
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Viewed:
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855 times
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On the following link under the section infrared you find
a good explanation of IR senders and receivers .
http://come.to/8051
Rgds
Johan
John Barnes wrote:
>
> Either I'm missing something, or there's a fundamental
> error in people's understanding of "IR".
>
> The "IR" in question is simply a transmission medium, which
> conveniently modulated in the 25 - 50KHz area can be detected
> against a background of low frequency light sources souch as
> household lighting etc.
>
> This modulation is in turn modulated at a "bit rate" convenient
> to the system its being used for, such as a tv or VCR remote
> control.
>
> What I don't understand is why you would expect an RCX transmission
> which is a bit encoding of standard computer style RS232 serial
> data at 2400 bps encoded as 10 bits total, start, 8 data and stop
> to match a proprietary transmission standard hatched by a tv or
> vcr designer who has no reason or need to use start bits, stop
> bits or 8 bit bytes! (After all, they owe their heritage to
> teletype machines!)
>
> I suspect univeral remotes that learn, learn bit patterns and
> nothing else. I know you CANNOT make a PC serial port do this.
> I don't know enough about the RCX's serial port but I suspect
> it is also using a UART of some kind, in which case it will
> not be able to transmit or receive arbitrary bit patterns
> either.
>
> Lego sell a perfectly usable remote for the RCX. I use mine
> all the time.
>
> JB
>
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Message is in Reply To:
 | | Re: ir tower -> consumer electronics
|
| Either I'm missing something, or there's a fundamental error in people's understanding of "IR". The "IR" in question is simply a transmission medium, which conveniently modulated in the 25 - 50KHz area can be detected against a background of low (...) (25 years ago, 27-Apr-00, to lugnet.robotics)
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