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

[Charles Goyard]

Hi Julian,

The commands I gave and to be run as root.
so:

sudo bash
echo gpio17 > /sys/class/gpio/export
echo out > /sys/class/gpio/gpio17/direction
chown charles /sys/class/gpio/gpio17/value
exit
pd &

Can you post the full command set you tried ?

It seems there's an overall consensus on running pd (and all kinds of
other stuff) as root on the pi. I don't agree with this but that's life
and I don't use the pi much anyway.

Cheers,

-- 
Charles

Julian Brooks wrote:
> Hi Charles / list,
> 
> Can I ask you/anyone a question re: permissions for accessing the gpio pins
> please?
> 
> Currently I can't get past:
> "echo gpio17 > /sys/class/gpio/export"
> which gives me "permission denied" with everything I've tried.
> 
> Are you using WiringPi to allow access to the gpio and if not how?
> 
> I'd like to stick with Miller's [gpio] object
> http://crca.ucsd.edu/~msp/syllabi/206.13w/index.htm
> (found in the earlier split thread - apologies for the noise)
> and keep as much within Pd as possible.
> 
> Best wishes,
> 
> Julian
> 
> 
> On 28 January 2013 14:14, Charles Goyard <cg at fsck.fr> wrote:
> 
> > Hi list,
> >
> > I could make use of gpio (as output) within pd with just [textfile] :
> >
> > on the command-line:
> >
> > echo gpio17 > /sys/class/gpio/export
> > echo out > /sys/class/gpio/gpio17/direction
> > chown charles /sys/class/gpio/gpio17/value
> >
> > inside pd:
> >
> > [ set 1 (  [ write /sys/class/gpio/gpio17/value cr (
> > |
> > [ textfile ]
> >
> > works.
> >
> >
> > I use it to drive a light system from a track of a audio file containing
> > only square waves at a given frequency (say, cues embedded inside an
> > audio file).
> >
> > I basically snapshot~ and see if it's over or below 0, and turn the gpio
> > on/off on change.
> >
> > I started using pd on the pi three hours ago and have it playing audio and
> > banging the gpio in no time.
> >
> > Thanks to all for this wonderful community.
> >
> > I'm very happy ;).
> >
> >
> > --
> > Charles
> >
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