I made a Pd instrument with a Raspberry pi and arcade buttons. The buttons are connected to the Pi’s gpio, and now I’m trying to interface them with Pure Data.

There’s the disis_gpio external in Purr data, but I’m having trouble since it seems more suited to output. For triggering events in real time, I’d have to set a metro object to constantly refresh disis_gpio. Will that create a lot of CPU overhead?

Besides that, I’m just lost trying to use it with button input. I found out that the pin numbering is not the same numbering in RPi’s documentation, gpio drivers might need to be started manually, and I’m unsure if the external includes or needs the wiringpi library.

Usually I can trial and error these things, but I have no idea where to start troubleshooting. Any advice on using disis_gpio for this? Are there alternatives? I know there’s Pd-wiringpi, but it also doesn’t use the library’s interrupt thread for input. I’ve heard of Miller’s own GPIO object, but I believe that’s only part of an outdated Raspbian image he created a while back.

@not.tachyons This might help..... unless you have seen it already......... https://www.researchgate.net/publication/266559610_Pd-L2Ork_Raspberry_Pi_Toolkit_as_a_Comprehensive_Arduino_Alternative_in_K-12_and_Production_Scenarios?_sg=QU6yIxrkSvm7RcjKSGqK8wkUaWqCRDQeImsvtJnJgD9lhmwOiWE-3Lb8CSJb1rhPN8lW6j1O9Q
Python, pdsend, pdreceive and [netreceive] is an alternative if you have some Python skills.
I am having other problems since lightning destroyed my RPI B and I was forced to buy a RPI3 (if anyone has old working RPI's then put them on Ebay..!).
WebIOPi (that I was using to set pins) seems to be unsupported and broken at the moment.
As GPIO is about the only reason to buy an RPI I am surprised that there is so little (easy setup) support for noobs.
David.

@whale-av I have seen that, and it looks like I’ll just have to put a lot more time into it. I’m hoping I can set everything else as creation arguements besides just the pins.

I’ve seen others use python and proccessing to go through netsend, that just might be easier and more efficient.

And if lightning struck down my Pi, I’d just assume it was meant to be for some reason haha. I believe you can get the new 3 B+ on adafruit or amazon. The Pi zero’s are $5, with wifi/bluetooth $10, and adafruit sells one with pre-soldered headers.

The Zero’s are based on, but faster than the older single core Pi’s, but I’d go for a multicore one myself. In linux, you can set the OS and any other cpu overhead to run on one core, and set the others for instances of Pd and Jack2 (2 uses multiproccessing). It gets you pretty close to running Pd hard real-time. I have yet to set that up on mine though.

Besides that, you can use netjack and Pd’s net objects to cluster Pi’s, and break up a complex patch or spead multiple ones across them. If you can set them up, these little affordable things can theoreticaly do much more than any Laptop.

Update: wiringpi’s gpio utlity works fine, but it isn’t loaded by modprobe as that link says to do. The Disis_gpio help patch is all errors trying to locate pins. This is when running as sudo, which Pdwiringpi recommends so it can read pins directly. Root disis_gpio looks for pins in the same slow way as non-sudo Pdwiringpi, but it fails to find the gpio directories in the error messages.

The k12 module flag doesn’t seem to do anything as far as I can tell. I know updates to wiringPi have broken the object before, but I have no idea what’s going on. Puckette’s gpio object and PdwiringPi are outdated and difficult to figure out. So a simple gpio netsend script seems like it would be far easier and more reliable.

Another update, because I finally figured this out and haven’t seen a proper solution anywhere else. So if someone else searches for how to do this, hopefully this will help.

Go install adafruit’s retrogame script. Assign pins to keyboard keys (there’s a list of game specific keys you use), and use the various key objects in Pd to read the values triggered by buttons. Its simple and foolproof, the script runs on boot and is written in C, keyboards and key objects will always work, and its built right into linux and raspbian. No python, no figuring out which of the many ways to script works best for real-time, no ports or servers, no buggy externals that depend on and get broken by other libraries, it just works.

I realise I'm responding to a 5 year old post here but:

has anyone had success with using the retrogame script recently? I've installed it on a Pi and it just does not seem to convert my GPIO button press into a keyboard input. If I look at GPIO status I can see it changing when I press the button, but there is no keypress generated anywhere.

@yannseznec I tried it once but haven't had luck. Also tried the mcp3008 with GPIO but.. idk the chip got super hot and smelled like plastic. I think I put the ribbon cable the wrong way. Anyway- let me know if you have success with this. Getting all the gpio pin errors with wiringPi. I know it's deprecated.. and with a pi5 idk. Think I need to flash my sdcard and start over and stick to one method. Have an Arduino nano and can't get that to work in pd either but that's a different story. It's worked in the past. I need a version of grasshopper java learning app but it teaches Python instead. Sorry to rant, anyway huge fan of pure data. Used it to make an on-air light at my job with midi and osc last year! I need to post it somewhere.