[PD] how to install and use GPIO external

Josh Downing jndowning at gmail.com
Wed Jun 19 19:07:14 CEST 2013

Thanks Jaime, that fixed my error problems. No errors now but I can't seem
to figure out how to set the patch up to configure GPIO 17 as an input and
then to read the state. I modified gpio-help.pd to do this by changing
"output 1" to "output 0" (according to the patch output 0 should configure
the pin as an input). I then click "enable 1", "open 1", and then "output
0". No error messages but where should I expect to see the high/low state
of GPIO 17? Should this be reflected in the bang object in the script
(white for low and black for high)? I have the poll input check box
checked. When I toggle the voltage on GPIO 17 from 3.3V to GND I do not see
anything change in the script. I am able to see the high/low state of the
pin 17 change by using the "readall" command from LXTerminal so I know that
I'm switching the voltage correctly on the right pin, just not seeing how I
get this status in pure data using the gpio-help.pd script. Any thought on
how I do this?

Sorry I have very little experience with pure data and am just learning.


On Wed, Jun 19, 2013 at 11:17 AM, Jaime Oliver <jaime.oliver2 at gmail.com>wrote:

> you need to be root.
> start pd with sudo. unless there is a more permanent solution by now?
> best,
> J
> On Wed, Jun 19, 2013 at 6:02 PM, Josh Downing <jndowning at gmail.com> wrote:
>> Thanks for the help guys! So I deleted the "-m32" from the makefile and
>> then everything seemed to build okay. I then added the correct path for the
>> extension in pure data and loaded the "gpio-help.pd" patch without getting
>> an error message. In the gpio-help.pd patch I would click "enable 1" and
>> then click "open 1" and after clicking "open 1" I would get an error
>> message: "/sys/class/gpio/gpio17/value: No such file or directory".
>> I then realized that I probably needed to install wiringPi. I downloaded
>> this and installed it. However I would still get the previous error message
>> within PD. I then decided to manually try to create the file using commands
>> in LXTerminal. I did this using this command, "echo "17" |sudo tee
>> /sys/class/gpio/export". I then noticed that the gpio17 folder and
>> accompanying files were created. I was also able to correctly read the
>> state of the pin using "gpio readall" command from LXTerminal.
>> I then loaded the "gpio-help.pd" file again in PD. Now once I click "open
>> 1" instead of the no such file or directory error I get
>> "/sys/class/gpio/gpio17/value: Permision denied" error. Is there someway I
>> can use this GPIO library within the PD visual interface without getting
>> permission denied errors? Also, shouldn't clicking "enable 1" within the
>> gpio-help.pd patch create the "/sys/class/gpio/gpio17" folder and
>> accompanying files? How can I get this to work within PD without having to
>> run the commands from LXTerminal to create the folder/files? Do I need to
>> somehow indicate to pure data the path of wirngPi?
>> Almost there! Really appreciate your guys patience with me and help on
>> this!
>> Josh
>> On Wed, Jun 19, 2013 at 6:31 AM, IOhannes m zmoelnig <zmoelnig at iem.at>wrote:
>>> Hash: SHA1
>>> On 2013-06-18 23:37, Josh Downing wrote:
>>> >
>>> >
>>> > cc -DPD -O2 -funroll-loops -fomit-frame-pointer
>>> > -fno-strict-aliasing -Wall -W -Wshadow -Wstrict-prototypes
>>> > -Wno-unused -Wno-parentheses -Wno-switch  -I../pd/src
>>> > -I../../pd/src -I../../../pd/src -I../../../../pd/src
>>> > -I../../../../../pd/src -m32 -o gpio.o -c gpio.c cc1: error:
>>> > unrecognized command line option ?-m32? make: *** [gpio.l_i386]
>>> > Error 1
>>> >
>>> > Do you know what this error message could mean?
>>> it means that the makefile has a compiler flag "-m32" which is not
>>> known to the compiler.
>>> > What should I expect as the output from compiling like this?
>>> nothing. the build failed.
>>> you could try editing your makefile and removing the "-m32"
>>> occurences, and see what you get then.
>>> make a backup of the makefile, before you go ahead.
>>> fgamsrd
>>> IOhannes
>>> Version: GnuPG v1.4.12 (GNU/Linux)
>>> Comment: Using GnuPG with Icedove - http://www.enigmail.net/
>>> iEYEARECAAYFAlHBlqMACgkQkX2Xpv6ydvSjtACg7y5vI4qGYDwjphUooM/Yt+RZ
>>> /KcAoKpb6waukrnp35DZQGFYmP88XAVD
>>> =0t/E
>>> -----END PGP SIGNATURE-----
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> --
> **********************
> Jaime E Oliver LR
> www.jaimeoliver.pe
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