Help needed with project

#1

Hi there fellow axolotians.

I have built myself a portable jamming device, with a mixer, midi thru, clock sync, midi/usb, speaker and last but not least, an axoloti.
I have spent a lot of time on the actual build and I'm yet to go deep into the Axoloti patching.
In the first pic you can see the actual "box", with the breakout for the axoloti in the top right corner. The second pic shows the case it will be housed in.

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The axoloti will sit in the lid of the case, probably behind acrylic glass and wooden panels surrounding it, where there will be pots and buttons for it. I'm working on a Sketchup of the lid, but so far I'm not sure about the number of pots/buttons, and this is the part i need help with.

I want to be able to use it as a stand alone synth, and being able to cycle through a number of patches without having it connected to a computer. But I'd also like to be able to use it as an effect, where I could run some other synth through it. Normally I'm too much of a "do it yourself guy" to ask for help, but I figure there are plenty of wisdom to be drawn here, and some of you might have run in to some problems which I could avoid.

Obviously, the dream scenario would be to have an OLED for navigation (and waveform visualization). But sadly that would be far above my current level in electronics/programming. I'm normally up for a challenge, but I think my GF would hang me by my balls if I take on another project of that size (might leave room for a display in the panel though, for future endeavors :wink: )
So if I understand it correctly, I can use 15 analog inputs plus 4 digital in/outs. Read about using a analog rotary switch in another thread, I think I won't have that many patches loaded at a time, so that'll probably be enough. I aim to build my patches in such a way that the panel with pots make sense with different patches..

Feel free to brainstorm with me, I'd love suggestions of all sorts since I'm still in the planning stage.

  • What would be the best way to toggle through patches?
  • Use a button to switch between synth/effects?
  • Thoughts on pot groupings (i.e x for waveform manipulations, x for filters, effects etc.)?
  • I'm thinking about having the Axo behind acrylic glass. Would be nice to get the logo on the glass maybe? Some leds?
  • Visual feedback for selections, is it needed? Leds take up pins..

Well, gotta go to bed, but it would be really awesome if anyone has ideas how to make this as good as I want it to be :slight_smile: Cheers!

#2

That wood work looks really cool.
I am using exactly the same case and concept for my build, but rather than building a Synth (as I am not a Synth man) I am building a bass guitar effects system, that will use Synth concepts to drive and control the effects.
I probably can't offer any insight to Synths but maybe if I give you a basic rundown on what I am doing, might give you some idea's.

In the lid of my case I have mounted a used VGA monitor which will be driven by an Arduino due, which will be mounted into the main case with the Axo in a small wooden box, just enough to fit it all in which I can remove and connect to my desktop pc when working on patches etc.. Then the rest of the case will be made up of various external pre-amp and effect units I will also connect. To control it all, I will have a 10 footswitch board I built, 2 of the switches are for changing the banks, and a delayed option in the switch for switching between parameter adjustment and patch selection. Everything has been designed to be foot controlled. The parameter adjustment uses the other 8 switches as follows.. +16, -16, +4, -4, +1, -1, select parameter +1, select parameter -1. The select parameter option will allow me to select up and down between 32 parameters and change their values up and down by the increment level, all linked through the patch by "Internal Midi" objects. When not in Parameter adjust mode, the 8 momentary switches of 4 banks total 32, can switch on and off as I wish etc through the patch. All these changes will be reflected on the VGA Monitor. All the objects required to do this, will all be setup as a subpatch to be used in every patch.

One last thing I have done / doing, maybe a bit unusual, as much of the build as possible except the case, will be painted in black chalk board paint, I thought this I could use this to use signs of what is what, could also draw in a colored 6 legged Axo mascot, and can remove, update and change whenever I want.

:grin:

#3

Thanks man! Not my best woodwork though, I haven't got any good tools at home and had to make some compromises.. I'm a bit sad I chose that case though, bought it first and designed the speaker and everything after it. Now it seems stupid to use a cheap case for 20 bucks when I've spent hundreds on the rest..

I've seen a couple of posts showing your monitor and interface, how far have you come and do you have any new videos/pictures? How much work is it with the arduino to get it to work with a monitor? And how hard is it to make an interface? I'd really like a display for my Axoloti as I said, but I'm a bit afraid of the workload:)

The blackboard idea is really cool! There are some thin pens with liquid chalk, so you could also write the parameter names and stuff!

#4

Great Project, nice idea the case. I'm thinking of a similar system too.
I've found myself needing some visual display for my axoloti boxes. As I've already wired up 7 boxes, and not put more than one led on each box, I needed to do something smart. So I'm thinking of making a simple box using a arduino, a Graphic LCD 84x48 - Nokia 5110 screen and a midi in and out. As I rarely use the midi din ports on my axoloti, they would send over a midi information that would be read by the arduino and printed onto the LCD. It would work on a 9V battery and could be used on any of my boxes. The simple version would just be a midi in, and a more elaborate version would have extra buttons, a few extra pots and a few leds that could send information via midi out.
I know it's a bit of a strange solution, but it seems do-able with my limited knowledge and not too expensive.

#5

Using a VGA monitor is not for everyone, but I chose it because they get thrown away so they are free, and the circuit seemed very simple, and it you just download the library and of you go. But you will need an Arduino Due, they can be sourced off ebay quite cheap, but if you haven't used Arduino before then it might be slow to get started. The link with all the info is https://stimmer.github.io/DueVGA/
You don't even need a VGA monitor, you can even use an NTSC / PAL tv instead. The code controls are very simple, you can even build your own fonts if you don't like the default ones, I built my own smaller font to save space. All the communication between the Axo and Arduino is done via the serial pins. I just send 8 bit values from the Axo, which trigger certain conditions on the Arduino and change info on the display.
I have built many working scenarios, but none which I have been happy with. They just seam too much, I want to simplify it, the "Keep It Simple Stupid" approach. !:disappointed:
And I forgot to add, I have an SD card connected to the Arduino Due, it will hold button and parameter info for each patch which can also be displayed so I know what does what. I built a simple little desktop program to allow me to manage this info as things change. So I can update it as I am building the patches.

My biggest problem is as I continue to learn about stuff, my ideas get more complicated, and I get further away from completing something, and this is bothering so much, that everything is now in reverse. Pulling everything back to the bare minimum of what I need to complete the build with all the flexibility available to add without having to make major changes. :grin:

#6

I am myself still new here so I do not have to many specific tips for you but since I have done my fair share of hardware customization projects I might be able to give a few general pointers.

Basically the great thing about Axoloti is that you can decide on your interface yourself. The most logical path to choose would be to:

1 - select or program the instruments you want to use
2 - study what in- and out options Axoloti offers. Will you only work with hardware tie ins or is an existing MIDI hardware also an option?
3 - decide which parameters you want to control directly
4 - make a list of these
assuming you go for hardware tie ins:
5 - specify behind every item in your list what physical controller you need (switch, pot, slider, etc).
6 - check what specs each part must have to be "understood" by Axoloti
7 - make sketches to work out what would be an acceptable layout for you.
8 - Only when you have solved that whole puzzle: Get hold of the parts with the right specifications
9 - Build a wires only workbench prototype. So Axoloti with in and output devices attached.
10 - Test it thoroughly
11 - Make a drawing of your definitive interface in Sketchup or something similar
12 - Print that out on the correct size.
13 - Take over the hole positions
14 - start drilling, sawing, swearing, etc.

In other words: Building the actual interface surface will come last.

The best interface is the one that let's you do all the emediate stuff you find important without the rest being cluttered up with stuff you hardly ever use anyway. So if you are a typical live filter tweak man you'll propably not want a whole bunch of envelope generators on there (I would!). Such more esoteric stuff you can still tweak on your software host.

Does that help?

#7

Thanks for the input, all of you.

After reading brasso's post, I think I'll just have to calm down a bit. Just finished the "base" now, got it sounding real good and I'm only waiting for the last USB extension before I can tie all the cables down and close the panels for good:)

During that part of the project, I came up with new ideas all the time and did not have the amount of control I should have had. It turned out good after all, but anything could have gone wrong at any time. This time I should really take a step back and think through the interface before I start to build anything. Had to re-solder some things in the mixer since I was too eager to get it up and running, rather get it right from the start this time!

I think I'll consider a display of some sort after all, since I've decided to slow down the plans a bit. I'll have to take a dive into the deep end and look at the possibilities. I'll also start to look at my favorite synths and pedals and really boil it down to the components I want.

I'll try to keep this thread updated with my ideas and findings so I can get continuous feedback :wink:

#8

Well, I have to confess that I started to write a general set of tips but spent little time to consider that you had already taken a lot of hardware decissions up front. Do not take that as critisism though. There is nothing wrong with being intuitive becaue it might also lead to interesting experiences and discoveries (as long as you do not blow too much stuff up What I described is a more concious path to get the most out of the flexibility Axoloti is offering. But you know what: I do not yet have an Axoloti myslef so I was talking a bit before my turn anyway.:grimacing:

#9

I've ordered some I2C OLED panels, some rotary encoders, an oscilloscope and a Teensy 3.2. I'm going to start out on a breadboard and see if I can get the stuff to talk to each other. I've worked a lot in Matlab, so I have some coding experience, but I'm not sure how much that is going to help me here though.. It'll be fun at least and I guess I'll just have to keep the Axoloti on the outside of the box until it all makes sense. I have to start making some patches so I know what kind of interface would be best.

From what I gather, I can have several I2C displays on the same bus right? Just assign different addresses? I'm playing with the thought to have one display per potentiometer, and have the Axo send the name and value of the parameter that the pot controls. Then a little bit bigger display to show a list of patches, a clickable rotary encoder to choose patch etc..

#10

Theoretically the sky is the limit. Do however consider what I said about the best interfaces not being too cluttered. Using displays can however be good way to give a controller multiple functions without having to revert back to the programming software. Have a look at the FutureSonus Parva for inspiration. It has a very nice interface. graphically uncluttered but by the use of such small displays still very versatile.

As far as I am concerned it ticks all the boxes.

#11

Yeah, that interface is really nice, I'd like something like that. I'm getting really eager to try it out now :smile:

Found this, so I should be able to use multiple displays at least. Though it seems I2C is limitied to 2 displays when i dug a little deeper, but SPI should handle it fine.

#12

This reminds me of the Oberheim Matrix which was one of the first synths to provide such an adaptable interface.