I’m new to raspberry pi and am trying to run Pure data on it to control a teensy 3.2 using Open Sound Control which in turn controls some stepper motors for a pump just like here https://github.com/DropletKitchen/pumpsn17 (using the teensy code and PD files provided at the end of the page). I’ve finally managed to install PD extended on my raspberry pi 3 (Raspbian Jessie). But I don’t think PD is able to use the USB to communicate with the teensy, since if I try to run the PD file, PD gives me the error “could not open device /dev/ttyS0: failure(13): Permission denied. Could someone help me please to get PD communicating with OSC through my USB?

Also when I open PD I get this message
“/dev/dsp (read/write): No such file or directory
(now will try write-only…)
/dev/dsp (writeonly): No such file or directory
/dev/dsp (read only): No such file or directory”
and
“Audio I/O stuck… closing audio”
Do I need to do some further configuration to get Pure Data running properly?
Like I mentioned I am very new to using the raspberry pi so any help would be appreciated and please do explain as if I were an idiot, that would be very helpful.
Thank you

in a terminal window, type

sudo adduser <USER> dialout

where <USER> is your user name. log out, log in and you should be good to go.
Cheers

sudo chown <username> <file name> (Claim ownership of a file)
sudo chmod 777 <filename> (assign read/write permissions for all users to a file)

Hope that helps

Either give it a network port......... https://forum.pjrc.com/threads/40238-Teensy-3-2-with-WIZ820io-and-OSC ......or convert your messages within PD from OSC to TTY data and use the USB connection.

However, looking at your OP link it seems that is exactly what is happening in "pumpsn17".
The patch [slipserial.pd] is doing the conversion to the teensy datastream.
So it is using the tty port and you should have a working system.....

Is [slipserial.pd] looking through the USB port to the pins on the Teensy...... is any voltage appearing on Teensy "S0".

More info here......
https://github.com/CNMAT/OSC
David.

I would try..........
To find the "devicename"........ https://unix.stackexchange.com/questions/144029/command-to-determine-ports-of-a-device-like-dev-ttyusb0
So.....

#!/bin/bash

for sysdevpath in $(find /sys/bus/usb/devices/usb*/ -name dev); do
    (
        syspath="${sysdevpath%/dev}"
        devname="$(udevadm info -q name -p $syspath)"
        [[ "$devname" == "bus/"* ]] && continue
        eval "$(udevadm info -q property --export -p $syspath)"
        [[ -z "$ID_SERIAL" ]] && continue
        echo "/dev/$devname - $ID_SERIAL"
    )
done

David.

sudo apt install alsa-oss
sudo modprobe snd-pcm-oss

in the command to create a /dev/dsp device as per the advice of another raspberry pi user. Not sure why there is the difference with Pd extended and Pd L2Ork but I don't think this is where my problem is.
If I actually open the Pure Data files that I need, in either of the Pd program versions I get:
UnpackOSC
… couldn’t create
routeOSC /derection
… couldn’t create
And then a bunch of other could not create warnings for all the OSC parameters. It seems like the OSC elements are not working. The PD L2Ork also identifies that the helper file o.io.slipserial.pd 5 0 4 0 (bng->loadbang) connection failed
Suggesting the communication between the “loadbang” control in the PD file and the helper file. although I am assured the PD files work. I’m trying to get in touch with the creators (to no avail). But if anyone here has any helpful suggestions I am all ears.

[unpackOSC] and [routeOSC] are from the MrPeach library.... included with extended.
If you look in Pd/extra/mrpeach you should see the help files for them (you will not see them as objects.. as they are part of a library). Usually putting an object [import mrpeach] in the patch will make them work..... it forces Pd to load the library.
So it looks as though the patch was built with extended.

A connection fails when an object does not have a specific inlet or outlet for some other object to connect to as the patch is loaded... maybe because the object has not been created......
IT LOOKS LIKE..... the object [loadbang] that you have does not have an inlet (mine does).....
Just connect the bang to the same places as loadbang....... that will do the same job.

Out of interest, what did running the code in my last post (in terminal) tell you about the dev/tty connection?

PS................ I have downloaded it. [import mrpeach] has been added to [o.io.slipserial] so unless that is opened first (unlikely) you will get errors.
Add it to the patch that you open first (or all of them...... no harm can result)

PSPS............ In [Hardcoded4Pumps] clicking the [devices( message should print a list to the Pd window. This should do the same as running the code that I posted yesterday.
In [Flexible3or4Pumps] the same....... plus a radio button below to select the port.....
David.

Google will have to be your friend for the "packet size is not a multiple of 4 bytes: dropping packet" problem. Google throws up quite a few discussions that are relevant......

Someone mentioned it in this thread...... https://forum.openframeworks.cc/t/sending-osc-over-slip/18306/20 ........ and although no-one answered there was a lot of discussion of the microprocessor side of the tty connection....... etc.

But this might be more useful...... as I expect that it is a problem with the data being sent back from the Teensy.......... https://cycling74.com/forums/max-receive-udp-message

David.