Gate/Trig Output from Axoloti Pin outputs

#1

Hi,

I've just started my journey into the world of microcontrollers so apologies if my post doesn't make a lot of sense.

After taking apart an audio damage neuron module and noticing an ARM STM32 chip on it, a few google searches later and I found axoloti! So i'm keen to start learning the world of DSP... I've done some very basic stuff with arduino and have now started doing some video courses on Udemy for C++ using the eclipse IDE. My goal is to prototype something using axoloti and eventually if things go well - develop a eurorack module in the future using a Nucleo/Discovery development board.

As a starter I'm wanting to design an extremely basic 2 track 8 step drum sequencer. I would like to generate a gate/trig signal from the sequencer, an LCD for tempo display, and two buttons to switch between each track along with a basic start/stop button.

The thing i'm having trouble with the most is integrating circuits with a development board. Would i build the sequencer in axoloti, take a pin out and boost the voltage up to 5v, would it run off 2 pin outs (1 for each track.)

If anyone can point me to some basics it would be greatly appreciated!!

Thanks johannes for creating this great piece of kit! :smiley:

P

#2

I've just ordered some of these boards to do something similar:

The idea would be to use the Axoloti as a sequencer and output 3.3V pulses/gates on the GPIO, and convert them to 5V using the SparkFun boards so I can trigger eurorack modules.

Here's an overview of the GPIO pins:

You can use just about any pin as digital in/out. So these will be used for buttons and output jacks.

Haven't done anything with screens yet, but this thread might be a good start:

#3

Thanks janvantomme this helps a lot. Will check those sparkfun boards and draw a schematic will post to make sure i'm getting things right if you can check. Sounds like what you have planned is similar to what I want to achieve! :smiley:

I noticed the sparkfun board needs both supplies to work - could i take the 5v direct from my eurorack psu and plug into my breadboard?

I'm thinking of building the mutable instruments module tester to get eurorack power into a breadboard - does anyone know if theres anything else on the market I can use to do this?

Thanks
P

#4

Hey @planckepoch :slight_smile:

Depending on how deep you want to go and how much you want to solder, you could also take a look at this solution. Its for people like me who doesnt like soldering :slight_smile:

All though it is not based on the pin outs, I think it could be a simple solution for getting a bunch of gate/trigger outs from axoloti. You get 12 gates and 4 CV outputs, via midi.

But I guess it depends on the project.

Anyway, check it out, its called CVOCD. I got one of his USB hubs, its awesome;

#5

This is just what I've been looking for. If you have succes with it, please let me know and provide some info about the setup! :slight_smile:

#6

Was it an easy setup on the axoloti to send v/oct?

#7

Oh the one I have from hothkiss is not the CVOCD one, it was this one below. SOrry I cant tell you how the OCD CV works I dont have one as I dont have any eurorack to hook it up to, I just noticed it cause i had a plan to buy some euro rack at some point. But dropped that again, Axoloti is fine for me :slight_smile:

I have one similar to this one. He doesnt sell the one I have anymore, but htis one is the sam, ecept it doent provide internal midi clock:

#8

I think it might be possible to take the 5V from the Axoloti as well. Will do some tests when I receive my boards and other parts.

There's also this kit to get eurorack power to a breadboard, but they are sold out at the moment.
https://www.thonk.co.uk/shop/transient-breadboard-kit/

#9

Hi

jaffa thanks for the input - that unit looks good but im more wanting to learn design/circuits :smiley:

janvantomme - I checked that unit out, just waiting for it to come available again :frowning: do you have a schematic for it?

#10

Nope. It's on my wish list as well.

#11

Hi all. New Axoloti owner.

I'd lke to control a XOX HEART with CV/GATE from Axoloti, sending midi to Axoloti.

I can't find anything to start with, don't want to buy CVOCD...

#12

Hi Sezare check out this thread for quite a deep discussion on cv on Axoloti, it also refers back to some other threads that also deal with the same topic, hope it helps. There was a project that piggybacked off the back of this one called Akso which had cv capabilities without any additional circuitry, unfortunately it is completely dead in the water, but this thread and the work by Kaos and others should get you where you need to go....

#13

Ok thanks. Checking that thread.