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?
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:
**broken link removed**