Subject:
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IR transmission, strange coding ?
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Newsgroups:
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lugnet.robotics.rcx
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Date:
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Sun, 4 Nov 2001 20:10:18 GMT
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Viewed:
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2019 times
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hi all,
I'm working on what I call an "InfraRed All module" , which should
become IR-tower, IR-sensor, IR-audio-remote, etc.
Measuring the IR pulses from the IR-tower I encountered the following
effects
According to what Kekoa Proudfoot found
"A '0' is coded as a 417us pulse of 38kHz IR, a '1' bit is
417us of nothing."
ok, nothing wrong with that.
But the startbit ( which of course = "1") also sends a 417 us puls of
IR.
The first stopbit (which is "0") is coded as 417 us IR,
and all following stopbits are nothing of IR.
Did anyone measured this ?
best regards,
Stef Mientki
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Message has 2 Replies:
 | | Re: IR transmission, strange coding ?
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| (...) I forget exactly how I measured this. I think maybe I hooked a scope directly to the LEDs then sent a constant stream of something to the tower and looked at the waveform on the scope. I don't remember noticing anything funny with the start (...) (23 years ago, 6-Nov-01, to lugnet.robotics.rcx)
| | | Re: IR transmission, strange coding ?
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| (...) As far as I remember (it's been > 10 years) startbits are 0, stopbits are 1. (...) This is strange, are you sure it is not the odd parity bit? (...) That's fine, 1 is the 'passive' and 0 is the 'active' level. Jürgen (23 years ago, 6-Nov-01, to lugnet.robotics.rcx)
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