Forum: Mikrocontroller und Digitale Elektronik IR recoder topic


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von Lê Q. (l_q)


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Hello everyone,
I am try to make IR learning remote by using microcontroller ( my item 
is EFR32 of Silicon labs)
I used to refer IRMP_English and IRSND to decoder and encoder IR signal 
and I was successful with protocols which are available in the IRMP 
Protocols.
but it will not work with strange protocols.
Do we need to decode it to be able to save it and emit it?
Is there any way we could capture the infrared signal, then save it and 
emit it without encoding end decoding it? because if encoding and 
recording will not work if there is a strange protocol.
I searched a lot of information on various forums but couldn't find it.

von Achim M. (minifloat)


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Lê Q. schrieb:
> Do we need to decode it to be able to save it and emit it?

Not necessarily. I'd use constant time interval sampling of the 
demodulated signal.

Good old Nyquist says if your sample distance t_s is less than twice the 
shortest distinguishable timespan t_d of the protocol, it should work.

N.b. the shortest distinguishable time span would be t_d=1msec if 4msec 
pulses and 5msec pulses must be distinct.

Lê Q. schrieb:
> because if encoding and recording will not work if there is a strange
> protocol.

Maybe you analyze the demodulated signal and compare to existing codes. 
If it partly fits, reuse some code from existing code implementation.

Is there a way for you to record the demodulated signal to a file? E.g. 
Logic analyzer? I suggest posting the file here.

von Lê Q. (l_q)


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Until now, there is no way for me to record the demodulated signal to a 
file.
So As you say: "Not necessarily. I'd use constant time interval sampling 
of the demodulated signal." Can you give me more information? I still 
don't quite understand.

von Kuno (Gast)


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Why you are not asking your question in the specific IRMP thread?

Beitrag "IRMP - Infrared Multi Protocol Decoder"

I guess there is a much higher chance to get an answer.

von Achim M. (minifloat)


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Lê Q. schrieb:
> I'd use constant time interval sampling

Recording
TSOP1136 -> MCU-pin -> sample with 10kHz task -> 10kHz bitstream

Replay
Timer 40kHz     -> MCU-Pin0
10kHz bitstream -> MCU-Pin1

(MCU-Pin0 & MCU-Pin1) -> IR-LED


By the way, the IRMP does allow for offline-Analysis.

Can you share some information about the device which you want to 
control?
Brand, type of device etc...?

br, mf

von Achim M. (minifloat)


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PS "demodulated signal"

Most IR remote controls use a carrier about 40kHz, which is then 
modulated
1
IR    ____|||||____||||||____ ...
2
      ____     ____      ____
3
demod     |___|    |____|     ...
4
5
demod is inverted, because most receiver IC have open-collecor-output
Simple receiver IC like the TSOP1136 or more modern ones (no idea what's 
available in your country) will demodulate i.e. remove the 40kHz carrier

: Bearbeitet durch User
von Lê Q. (l_q)


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Dear Kuno,
Thank for your help.
Because I am a newbie, I don't know about that.
So now I will go there to make question.
Thank you

von Lê Q. (l_q)


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Dear Achim,
Thank for your help.
So My device I need to control is Air Conditioner of Daikin.
And my goal is to create a device that can learn all the infrared 
commands and control them

von Achim M. (minifloat)


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Lê Q. schrieb:
> Air Conditioner of Daikin

This company does not make just one AC system. This blog here says...
https://harizanov.com/2012/02/control-daikin-air-conditioner-over-the-internet/
...there are at least 3 different IR protocols used by Daikin.

Maybe you compare the protocol found by  harizanov to the protocols 
already implemented in IRMP.

br mf

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