BTW - Forgot to add: I did read through this thread (as mentioned by Charles): http://www.raspberrypi.org/phpBB3/viewtopic.php?f=29&t=9667&p=198848 And left none the wiser... Seemed to me that there are several possible implementations, though I am completely unsure as to which one would work with the /sys/class/gpio/ method that [gpio] makes use of?
I think I'm going to be asking several possibly dumb questions around gpio until I can get my head around all this so apologies up-front. Julian J On 2 April 2013 09:46, Julian Brooks <[email protected]> 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 <[email protected]> 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 >> >> _______________________________________________ >> [email protected] mailing list >> UNSUBSCRIBE and account-management -> >> http://lists.puredata.info/listinfo/pd-list >> > >
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