jumpjack
Jul2-08, 02:14 AM
Sounds weird, but it is possible: you can obtain an infrared signal starting from an audio signal, and viceversa:
http://jumpjack.wordpress.com/2008/05/20/worlds-cheapest-remote-control-replicator-just-1/
But I miss something:
the old Griffin patent states that to produce a 38000 Hz signal using a 20000Hz audio output, you need to connect two IR leds to two audio channels, in such a way their frequencies sum up. Ok, it works; but I want to understand if same task can be accomplished with one single audio channel rather than two.
Somebody says it is impossibile; but I did this study:
Excel spreadsheet (http://www.planetmobile.it/jumpjack/ir2audio.xls)
Image (BIG!) (http://www.planetmobile.it/jumpjack/immagini/ledrem.JPG)
It looks like it should work.
Actually, it DOES work, if applied to the PC; but it does not if applied to my phone: in that case, only ONE led emits IR light, and I can't understand why.
Besides, I have a phone which is said to have "symetrical output", which is quite different from standard left/right channels output:
Nokia 6680 pinout (http://pinouts.ru/CellularPhones-Nokia/nokia_pop_pinout.shtml)
I'd like to include in my Excel sheet explanation about this phone, but I can't: any help? Which waveform results at L+, L-, R+ and R- pin upon playing a 38000 Hz sinusoidal signal?
http://jumpjack.wordpress.com/2008/05/20/worlds-cheapest-remote-control-replicator-just-1/
But I miss something:
the old Griffin patent states that to produce a 38000 Hz signal using a 20000Hz audio output, you need to connect two IR leds to two audio channels, in such a way their frequencies sum up. Ok, it works; but I want to understand if same task can be accomplished with one single audio channel rather than two.
Somebody says it is impossibile; but I did this study:
Excel spreadsheet (http://www.planetmobile.it/jumpjack/ir2audio.xls)
Image (BIG!) (http://www.planetmobile.it/jumpjack/immagini/ledrem.JPG)
It looks like it should work.
Actually, it DOES work, if applied to the PC; but it does not if applied to my phone: in that case, only ONE led emits IR light, and I can't understand why.
Besides, I have a phone which is said to have "symetrical output", which is quite different from standard left/right channels output:
Nokia 6680 pinout (http://pinouts.ru/CellularPhones-Nokia/nokia_pop_pinout.shtml)
I'd like to include in my Excel sheet explanation about this phone, but I can't: any help? Which waveform results at L+, L-, R+ and R- pin upon playing a 38000 Hz sinusoidal signal?