Thanks Thomas – damn, I thought all pins were 5v – I saw that there was a power pin at that level, and assumed the others were too.

So when you say "PWM is easily configured" - do you mean that it is some setting that I adjust on the Pi itself, and then getting a variable voltage is as simple as sending a value between 1 and 1023 from Pd to the Pi?

Or do I have to do some programming within Pd to do the actual PWM?  If this is the case – that's exactly what I need help with, not sure how to do that.

Thanks!!
Dan
--
Dan Nigrin / Defective Records / http://defectiverecords.com 
CycliC, M185 & Klee Sequencers / MC-4 & MC-202 Hack / Audio Plugin Player / General MIDI Player / Major Malfunction
Jack OS X / http://jackosx.com 

From: Thomas HOCEDEZ <thomas.hocedez@free.fr>
Date: Wednesday, July 24, 2013 5:34 AM
To: J Oliver <jaime.oliver2@gmail.com>
Cc: PD List <pd-list@iem.at>, Daniel Nigrin <dan@defectiverecords.com>
Subject: Re: [PD] gpio on the raspberry pi from within pd ?

Hi !

PWM on RPi is easyli configured, with a value from 1 to 1023.
Be careful only some GPIO are PWM : https://www.modmypi.com/blog/raspberry-pi-gpio-en-franais

The voltage output will be 3V3 @100%, I have to check this, but pretty sure.

REgards.


¤º°`¯ ¯`°²º¤æ=¬« Thomas HOCEDEZ »¬=椺²°`¯ ¯`°º
                www.asthrolab.fr

De: "J Oliver" <jaime.oliver2@gmail.com>
À: "Dan Nigrin" <dan@defectiverecords.com>
Cc: "PD List" <pd-list@iem.at>
Envoyé: Mercredi 24 Juillet 2013 11:13:10
Objet: Re: [PD] gpio on the raspberry pi from within pd ?

Hi Dan, 

I am Cc'ing the list, which is really your best resource. I haven't output variable voltages from the pi, but I am sure a lot of people have experience with this...

best,

J

On Jul 24, 2013, at 4:39 AM, Dan Nigrin wrote:

Hi Jaime,

Saw this post of yours from back in April re: GPIO access from within Pd on the Raspberry Pi:


I'm a total Pi newbie – I don't even own one yet.  I'm considering a project with it though, where I would like to use Pd to generate some audio, and to output it to another device (a Mutable Instruments Shruthi synth filter board).  However, I also need to generate control voltages that need to get sent to the filter board, to control its various parameters (e.g. cutoff, resonance, etc...).  I also need to send +5v and ground to the filter board.

So from your post, it seems quite straightforward to be able to access the GPIO pins from within Pd.  But I need to be able to create variable voltages (between 0 and 5v) on those pins.  In the post above, you mentioned that you send a float to the gpio object to write a value to the pin - would sending a 0.5 for example give me 2.5v on the pin?  Or is it only on/off (0 or 5v)?   If the former, I'm all set!  If the latter, I'll need to figure out how to simulate a reduced voltage at the pin (likely using PWM or something – but I'm not really sure how I would do that…)

Any help greatly appreciated!

Best,
Dan
--
Dan Nigrin / Defective Records / http://defectiverecords.com 
CycliC, M185 & Klee Sequencers / MC-4 & MC-202 Hack / Audio Plugin Player / General MIDI Player / Major Malfunction
Jack OS X / http://jackosx.com 



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