[PD] gpio on the raspberry pi from within pd ?

[Dan Nigrin]

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
<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 <http://jackosx.com/>

From:  Thomas HOCEDEZ <thomas.hocedez at free.fr>
Date:  Wednesday, July 24, 2013 5:34 AM
To:  J Oliver <jaime.oliver2 at gmail.com>
Cc:  PD List <pd-list at iem.at>, Daniel Nigrin <dan at 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 at gmail.com>
> À: "Dan Nigrin" <dan at defectiverecords.com>
> Cc: "PD List" <pd-list at 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:
>> 
>> http://lists.puredata.info/pipermail/pd-list/2013-04/102172.html
>> 
>> 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
>> <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 <http://jackosx.com/>
>> 
> 
> 
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