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

[Julian Brooks]

Hey Charles,

Thanks for the prompt response.

After sudo bash I get:
root at raspberrypi:/home/pi# echo gpio17 > /sys/class/gpio/export
bash: echo: write error: Invalid argument

The previous commands I tried were sudo'ing everything and also 'sudo -i'.

OAN:

Dumb question #256
I'm presuming 'gpio17' is to allow access to pin 17 and not what was my
first impression that gpio17 allows access to all 18 pins?

Best wishes,

Julian


On 2 April 2013 10:35, Charles Goyard <cg at fsck.fr> wrote:

> 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
> > >
> > > _______________________________________________
> > > Pd-list at iem.at mailing list
> > > UNSUBSCRIBE and account-management ->
> > > http://lists.puredata.info/listinfo/pd-list
> > >
>
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