[PD] Re: [PD-announce] PWM in Pd

[Hans-Christoph Steiner]

On May 26, 2006, at 5:33 PM, Martin Peach wrote:

> Hans-Christoph Steiner wrote:
>> I just realized the answer to my question about getting positive- 
>> only  voltages from the sound card.  The DC filters will probably  
>> remove  the DC offset, therefore, the output voltage on a PWM  
>> signal will  also be centered again on 0, and therefore swing from  
>> negative to  positive.  I do remember getting some very low  
>> frequencies out of a  computer when testing speakers.  But I  
>> haven't actually tested this  [pwm~] object for electronics.  But  
>> it would be nice to have a very  well implemented [pwm~], so its  
>> great that this discussion happened.
>> I did use the [pwm] object with a MIDI-controlled relay box,  
>> worked  quite well at 30-60Hz on a biggish DC motor.
>
> But that sounds like you're sending MIDI messages at a rate  
> determined by the [pwm], so bandwidth is limited by MIDI  to ~1kHz.  
> Better to program your relay box to do pwm with the pulse width  
> controlled by MIDI, instead of using MIDI just to turn the motor on  
> and off.

Sometimes you make do with what you have in the amount of time you  
have. I make no claims that this was a great solution.  But it does  
work.

.hc


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