[mythtv-users] Where to buy CommandIR ?

[Brian Wood]

On Monday, August 02, 2010 02:55:41 pm Gert van der Knokke wrote:
> Chris Hoff schreef:
> >> Otherwise, you could try attenuating the signal reaching the STB's IR
> >> receivers with something like multiple layers of white copy paper. If
> >> you come up with something that works extremely well, do pass it on!
> 
> If these emitters are simple IR LED's why not attenuate the current
> through them by means of a simple resistor. Just keep increasing the
> value up to the point the receiver stops responding then use a resistor
> value slightly less than this. You could even use a adjustable resistor
> in the range from 1 to 10 k or so.
> 
> Good luck,
> Gert

LEDs are not like incandescent lamps, you can only reduce the current so much before you get below the firing point of the 
diode junction. You can't dim them the way you can a lamp, the usual way to dim LEDs is to vary the duty cycle, but that 
won't work when pulsing the diode for IR transmission.

You might try a dab of not-quite-opaque nail polish at either end of the IR link, it might take some experimenting to find 
a combination that works, transparency to visible light may differ from the transmission of IR energy.