[sdiy] MIDI/CV sync LED lit plastic panel?

[Ingo Debus]

Brock Russell wrote:
> 
> >my question wasnt about MIDI/CV converters, it was
> >about translating the CV to the LEDs intensity.  it
> >seems like it should be a simple thing!
> >
> >denshi
> 
> Driving the LEDs with a pulse width modulator will
> give you the best control. You can use something
> as simple as a 555 timer.
> Best results can probably be achieved by setting the
> frequency to around 1 kHz, LED drive current to 15 to
> 25mA, (depending on the LEDs used),  and varying the
> pulse width between 0 and 100% will give a very linear
> output.

Going MIDI -> CV -> PWM seems a little clumsy to me. The uP processing
the MIDI input could generate the PWM too. Perhaps there are even
MIDI-CV interfaces available that use PWM-type DACs? These DACs are
often implemented with the timers of microcontrollers. Then just the
filter needs to be removed and a LED driver added instead.

Ingo