#7

I’ve been looking at the new Raspberry Pi Zero N for exactly this application, which given its wireless/bluetooth capabilities would require changes to certain elements of this cookbook, but not many.

#8

Does that HARDWARE: ADDING CLOCK/GATE INPUTS work with the Bela platform or BeagleBone black?
How about schematic for outputs (gate and modulation)?

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#9

RPi’s GPIO pins are logic gates, meaning 3.3V is high/on, whereas 0V is low/off. Bela/BBB’s pins are analog ins. They will accept any voltage from 0-4V+ And the actual voltage value can be read from the pin. You will want a summing amplifier to convert bipolar voltages to unipolar, and also to scale the range.

You can use this calculator to find the right resistor values.

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#10

wow jason! really happy about that link – this is rocket science for me :slight_smile: … a really novice question (in line with this whole post kchkch):

am i getting it right that i simply need to adjust the values (and reproduce the circuit) on this page to convert CV also for arduino / teensy etc? i really know nothing about this stuff and am super eager to learn some more, but i’ve read that a good route to get analog voltage into the rPi is via one of these microcontrollers…

and what would happen if my input-signal over/understeps the voltages (-5/5) i’m preparing the circuit for? apparently this happens in eurorack-land?

thanks for this link, very appreciated!

#11

I certainly can’t claim to be an expert. Just now learning about these things for the first time myself.

And that calculator leaves a ton of wiggle room, so I’m not 100% confident about the best way to use it.

But you’d want to put your input ranges into the top two fields (for eurorack that’s usually going to be -10V to +10V or -5V to +5V) and the output ranges into the next two fields (0V to +4V for Bela.io). Then you want a reference voltage. I use an IC to get this and I’ve ordered 3.3V reference voltage ICs, if I remember correctly (all this stuff is sitting next to my breadboard right now waiting for me to get around to it). Then you play with the resistor values until everything lines up. You want to choose resistor values that allow you to use simple and common resistors, so you aren’t overspending on weird resistor values.

The circuit scales voltages. So, in the example above, -10V becomes 0V and +10V becomes +4V. You can make them scale to whatever you want. Just use the values appropriate for your use case.

The consequences of getting it wrong can involve releasing the magic smoke. For example, you really don’t want negative voltages of any kind going into a Bela analog input. It will fry the board.

As for out-of-expected-range voltages, I think you can protect yourself from that using diodes. This is something I haven’t investigated as deeply yet.

#12

this is great!!!, i just got two raspis for devel so i’ll do this for sure. I have already set up l2ork/purr I am also going to add Analog knobs and ins for them but i would love to use my monome stuff as an interface for the raspis. FUN

#13

BTW, it is essential to run headless for any heavy lifting [SPECTRAL/FFT, Long Sampling] IMHO

#14

@shreeswifty, any good tips / tuts for running this config headless?

#15

@dan_derks – i’ve updated the manual for the auto-booting procedure
(as i’m so terrible with this stuff, it took me aaaages! there are like gazillion ways to boot and this is the only one that worked for me after loads of approaches)

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#16

I really need to try this.

As I happen to only have a arduinome 8x8 at hand, I wonder, if your PD patch could be converted to run with an 8x8 grid.

Any chance to get a copy of that patch file?

#17

sure… but it’s super chaotic and barely tested! it’s really only a quick sketch of the big one one for now, to see how PDs working for me :slight_smile:
pdpatches v04.zip (38.0 KB)

#18

Thanks a lot, this will be quite helpful.
Some learning ahead, though.

#19

Great!
I tried this years ago on a 1st Gen raspberry PI and some python scripts (no way that thing would run PD smooth enough) This seems like a good approach. Haven’t got a Pi lying around but trying it on a PocketCHIP. So far so got, I’ve got the crashing serialosc deamon, but if I keep retrying it eventually looks stable…

to complete the pd-l20rk i had to “apt-get install libnss3”

PD lork installed and runs, but I can’t find monome, I will try and recompile serialosc as suggested above

#20

what’s that? :open_mouth: :face_with_raised_eyebrow:

#21

I haven’t found the right combination yet, I did checkout and compile the commit you suggested
still trying, tips apreciated, keep hitting the segfault

#22

this little toy :slight_smile:
https://getchip.com/pages/pocketchip

#23

are you booting into serialosc(d)? i started thinking that using some pauses in the bootscript before launching it helps – may have been imagination, how ever :slight_smile:

#24

this looks pretty neat! – am i understanding you right that you’re connecting the grid to it?

#25

yes, it has a USB port, and I got output while pressing monomebuttons while running “cat /dev/ttyUSB0” so it’s possible :slight_smile:
it runs some kind of Debian, lot’s of RPi packages also work for it (like the pd-l20rk arm7 version)

#26

Thanks for this tutorial, it’s been really helpful !
However, the Purr-Data part is a little bit problematic for me.

I’m trying to instal p2-2lork on Raspbian Stretch, at the moment there’s an issue with the dependencies (pd-l2ork : Depends: libgsl0ldbl (>= 1.9) but it is not installable).

I think there’s no release compiled for Stretch & Arm7 yet. I’ve tried to compile the program but this generates some errors and I can’t get a correct .deb

Anyway, it almost works with pd-l2ork-2.4.6-debian_jessie-armv7l.zip if I avoid the sudo apt-get -f install and to install some dependencies manually.

sudo apt-get -f install simply removes the pd-2lork package . I’m new to Linux, Debian and Raspberry Pi, so that was a surprise, it took me a few trials before I realize what’s going on.

Correcting dependencies… Done
The following packages will be REMOVED:
pd-l2ork

:open_mouth:

Do you know where I can post issues and ask questions about this software ? Is there a dedicated forum ? Or do you know how to make a clean install of pd-2lork on a pi3 with Raspbian Stretch ?

(I’ve tried PureData vanilla on Stretch, it works but it doesn’t seem to load Cyclone…)