Sujet : Re: Ir remotes
De : llc (at) *nospam* fonz.dk (Lasse Langwadt)
Groupes : sci.electronics.designDate : 20. May 2024, 11:50:22
Autres entêtes
Organisation : A noiseless patient Spider
Message-ID : <v2f6cv$3tvoi$1@dont-email.me>
References : 1 2
User-Agent : Mozilla Thunderbird
On 5/20/24 09:15, Don Y wrote:
On 5/20/2024 12:01 AM, Don Y wrote:
My understanding is that Ir remotes modulate an Ir "carrier" signal
in a particular pattern to express a particular "code" corresponding to
the key pressed/held.
>
And, that different "chipsets" use different carriers and encodings.
>
Is there a front-end that is tuned to the particular carrier
in the receiver? Or, is all of this done "digitally"?
>
I.e., with a fast-enough (Ir) photodetector, should I be able to
decode ANY signal from ANY "remote"?
And, before anyone mentions the obvious, I've already looked at lircd
which is the reason behind this post; why do they claim they can handle
ALMOST all remotes? Is this a limitation of their hardware implementation?
Or, timing problems in the way they try to process the raw video signal?
afaik almost all use a 30-50kHz carrier, nominally something like 38kHz,
I think the common IR receivers have build in bandpass filter, so it is just a matter of interpreting bits (there's a few common protocols)
I know that B&O (used to?) be an exception with a 455kHz carrier, I'm guessing because someone clever many decades ago thought to use an AM IF filter