World’s cheapest remote control replicator: just 1$ !
Pubblicato da jumpjack su 20 Maggio 2008
You won’t need anymore complex circuits & complex software to sample commands from your remote control and to replicate them; all you need is just two standard IR led, which you can afford for about 0.50 $ each, or maybe you can extract from a couple of old remotes.
This method was tested with a VIA AC’97 audio card; please report if you have any success with different cards.
What you need:
- 1 spare headphone cable (0$ if you already have it, 10$ if you need a new one)
- 2 IR led (0$ if you have a couple of old remote controls, 1$ if you need to buy them)
- audio recorder software, e.g. Audacity, opensource and multiplatform (Windows/Linux)
What to do:
3) Edit the resulting waveforms
5) “Replay” the waveforms:
a - Plug the emitter into HEADPHONE output of your audio card
b - Position the two leds just in front of your device
c - Press PLAY in Audacity: your device should react to the command you previously sampled.
NOTES:
1 - For unknown reason, playing the resulting signal in Audacity works fine to control my device; but if I save the signal into a WAV file and reload it in Audacity, playing it results in… nothing! Any explanation for this?!? FIXED: it was due to wrong carrier frequency of rebuilt signal, which must be HALF of the needed carrier frequency! (19 KHz for 38 KHz, 18 KHz for 36 KHz…)
2 - You can’t save the signal in OGG or MP3 format, because this format distort the original signal
Please report results of your experiments! Good or bad, please just report and share! 
References and credits at bottom of this page:
http://www.planetmobile.it/jumpjack/LedRem/
Available patents (not mine):
Infrared generator from audio signal source
IR receiver using IR transmitting diode
7 Giugno 2008 a 12:06
[...] 4) Add an IR led to your recipe, and you obtain an SMS-controlled remote-control. [...]
10 Giugno 2008 a 9:42
[...] look at this post to know how to: - build an IR receiver for the PC - sample a remote control - (create a WAV file [...]
13 Luglio 2008 a 3:28
I’ve tried this and it worked great.
I have one question:
Can I save this as a WAV file or something so I can use an iPod for example to reproduce de signal?
PS:Sorry for my english
14 Luglio 2008 a 19:00
Sure you can use the WAV files on your IPOD: my idea actually started from a similar project… to turn IPOD into remote!
But please tell me if yout Ipod accepts these files, or if they must be in a different format.
(number of channels, sample rate, bits per sample, bytes per sample).
28 Luglio 2008 a 7:23
I tried it and finally works correctly.
Some remarks:
1. I must invert recorded signal.
2. Transmitter cannot work without a simple amplifier.
These issues due to my soundcard (Via on my mobo)
Recording with Ir led is US patented:
http://www.patentstorm.us/patents/6701091/description.html
28 Luglio 2008 a 7:43
S5vi, thanks for your feedback.
Point 1) is a known issue, that’s way I updated my RAW2LIRC program in such a way it can “flip” the signal if required. Anyway, you can invert the sampling led to avoid this.
Point 2) is quite strange; I have a VIA AC’97 …
About patents: I knew using IR to play sounds was patented, not that recording IR through audio was too; anyway, anybody can use any patented technology as long as he does not sell it. That’s why patents are freely available online:
http://www.freepatentsonline.com/6931231.html
I should have added to credits, indeed…
I will, together with your link.