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Turn Your IPod Into A Universal Remote

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43617373

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Would you actually need their software and "device" or could you do this with any sound recording software a IF receiver and a IF LED?
 

reyarba

New Member
43617373 said:
Would you actually need their software and "device" or could you do this with any sound recording software a IF receiver and a IF LED?

In principle yes. Im just worried of experimenting with external circuits that could damage my IPod. I would try to follow the suggested devices. That way I know that it worked without ruining the IPod.
 

jumpjack

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Sorry for digging up this ancient thread, but I'm getting crazy since several days to find a solution to the issue discussed here!
I hope somebody can add something to what I'm going to describe to clarify the situation, in such a way we'll be eventually able to control our TV by using any audio-out capable device.

Why doing it?

Because also a cellphone has audio out capabilities; even VERY old phones. And very old phones cost a few bucks; and some of these old phones are actually programmable computers with GSM capabilities; if you choose a Symbian s60 phone, youìll be also able to easily program the device in Python. For example, you can program it to play a selected WAV file upon receiving a particular SMS.

Joining this together to the ability to reproduce remote controls data using audio-out, will result in...

... remote-controlling your video recorder using an SMS!

Wouldn't be cool? :D

So, let's clarify:

- a simple IR (InfraRed) LED (Light Emitting Diode) can EMIT or RECEIVE (depending on how it's designed) infrared signals.
- IR LEDs on remotes do not just emit IR signals: they emit modulated IR signals, at around 38 KHz
- an integrated IR receiver (as TSOP 1738) detects not just IR signals, but modulated IR signals: the "38" is for the carrier frequency; indeed you can find 1736, or 1740 or other fashions (and even 1136, 1138, or 1836, 1840... Don't know what first two digits are for; datahseets only show different driving currents). The output of such a receiver is (i'm quite sure...) not a 38 KHz modulated voltage, but a binary output corresponding to carrier present/not present.

So, connecting a TSOP 1738 to audio card should allow sampling remote controls codes; but then we need a transmitter, and I can't find anywhere an integrated IR transmitter, only receivers are available!

So, if we can figure out how to convert the "binary audio output" to "binary 38 KHz output", we'll obtain the desired "cllone" of the Griffin device.


Now the question:
is anybody able to design the schematic for the audio-to-IR converter?
Maybe using this ready made 38 KHz modulator or any other?

What we are trying to build is this:
 

jumpjack

New Member
Update:
looks I just found an IR encoder at 38 KHz:
http://www.holtek.com/english/docum/consumer/2_12e.htm

But this site looks even more interesting: a reverse engineering of Griffin hardware and software!
http://www.codeproject.com/KB/mobile/PocketBeamer.aspx

In a few words: the author supposes that TWO leds are connected to audio-out because each one is connected to one of the two 20 KHz stereo channel; sending properly phased signals to the two channels allows building one 40 KHz signal from two 20 KHz sources!

Author also explains how probably (he didn't dismount the device) sending a proper waveform to a capacitor inside the device allow charging it in such a way it can then provide additional power to leds, allowing wider range.

This is very interesting nad I think further investigations are needed.
 
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