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Post by m4vrick on Jul 22, 2021 7:54:18 GMT
Hello  I want to share with you the building of my first (but not last) module for my upcoming synth. It's called additive VCO and it's based on this project : note.com/solder_state/n/n30b3a8737b1eI'm only adapting it to the AE modular format and to my needs in term of building capabilities. As you'll see I'm getting ride of the Arduino card and integrating the 328P directly to the board with the minimal needed component, so I can keep it small enough the for the AE modular format. All my work is done with Fusion 360 and you can follow it here: a360.co/3j92FYoLet me know if you can be interested in having the final gerber file and parts list to make one yourself, I'm open for sharing it when it's done and validated. Here is some view of the actual status:    Don't mind the male connector for IO instead of female ones, I could not find a suitable model in the Fusion 360 library. Same for the pot which are not in the 3D part. |
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Post by MikMo on Jul 22, 2021 11:29:50 GMT
Now that's a cool project!
Mikael
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Post by tIB on Jul 22, 2021 15:04:29 GMT
Out of interest could the code be run on grains?
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Post by m4vrick on Jul 22, 2021 15:26:34 GMT
Out of interest could the code be run on grains? I have no idea, I dont know grains and if there is some kind of compatibility with the Arduino libraries. The Mozzi library is really optimized for the Atmega plateform and used some low level function to adress the output quickly enough to generate the sound. So I guess it'll not work on grains but feel free to try |
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namke
wonkystuff
electronics and sound, what's not to like?!
Posts: 654
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Post by namke on Jul 22, 2021 16:36:01 GMT
Out of interest could the code be run on grains? It could be possible - Grains is basically an arduino, and is programmed from the arduino environment. The latest Grains version also has a switch for Mozzi compatibility... wiki.aemodular.com/pmwiki.php/AeManual/GRAINS |
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Post by tIB on Jul 23, 2021 6:51:09 GMT
Thanks for the info - I should do some googling around mozzi, since other than the switch on my grains I know nothing of it. Good luck with the project btw - looks fun.
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Post by admin on Jul 23, 2021 7:01:01 GMT
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Post by m4vrick on Jul 23, 2021 7:46:23 GMT
It's interesting, I was not aware of this module.
As I see on the wiki page you could probably directly put this additive VCO on the grain module with a few changes in the source code.
The main change is not having CV and pot control separatly for all 3 parameters.
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Post by m4vrick on Aug 22, 2021 17:03:17 GMT
Hi everyone Finally back to this project after fighting Covid. I received the PCBs and most of the parts. Only missing the Atmega which will arrived this week. The first working module should be running before next weekend.  |
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Post by keurslagerkurt on Aug 31, 2021 14:23:48 GMT
Just started working in Arduino myself. Very interested in how this project develops & the hardware/coding stuff, might want to try building one myself too once you have sound demo's!
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Post by m4vrick on Sept 1, 2021 7:47:30 GMT
Thanks For now I have some issues, seems that finalizing the routing while having covid was not a good idea  I have 4 big mistake and I need to order new revision of PCB. But it basically work, I have some sound coming from the part of the module which is working. |
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Post by pt3r on Sept 1, 2021 7:57:05 GMT
This thing could be built with the DIY module, if you manage to squeeze all the caps on there along with your arduino.
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Post by keurslagerkurt on Sept 1, 2021 8:09:32 GMT
Thanks For now I have some issues, seems that finalizing the routing while having covid was not a good idea I have 4 big mistake and I need to order new revision of PCB. But it basically work, I have some sound coming from the part of the module which is working. I feel your pain! Just now testing the Fourth revision of my new pcb, still have a mistake somewhere... (But progress was made!) |
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Post by m4vrick on Sept 20, 2021 14:01:09 GMT
Finaly received to good PCB and builded the first proto.
And here is the sound of this module :
How does is sounds for you? interesting ?
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Post by m4vrick on Oct 8, 2021 8:47:11 GMT
It seems the sound output does not makes you reacting a lot  Anyway I'm continuing to work on this project, I'm using the same hardware to another module from the same guy he called Chord : note.com/solder_state/n/n681d2e07e324And I'm facing a strange problem: the sound is very bad with this one. It's noisy and with lots of artefacts. Everything is working perfectly on the Uno board, sound clear and very interesting. On my board with the same microcontroller it's awful. I've made lots of tests for now: - Directly on the Atmega pin : same result, very bad sound. - Exchanging the Atmega between my board and the Uno board: no changes. So it's not a problem from the µC itself. - The power comes from the master module and it seems as good as possible The only hardware difference between the Uno board and my reduced implementation is the frequency generator. I'm using a Ceramic resonator instead of a crystal oscillator. Does anyone have some experience with this kind of issue? do you think the resonator could generate some issues with the mozzi library ? |
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Post by keurslagerkurt on Oct 9, 2021 14:10:01 GMT
Cool to hear you are continueing further! I'm very interested in the Chord module. The Additive VCO sounds great, but about the same as the FMOS, so I've got my Additive fun already covered in the rack. the Chord module tho... That sounds like something i'd use all day!! For the troubleshooting, i'm not very specialized in atmega etc. However, maybe namke has an idea? I know he uses that microcontroller for his modules 😃 |
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namke
wonkystuff
electronics and sound, what's not to like?!
Posts: 654
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Post by namke on Oct 10, 2021 14:32:46 GMT
It seems the sound output does not makes you reacting a lot Anyway I'm continuing to work on this project, I'm using the same hardware to another module from the same guy he called Chord : note.com/solder_state/n/n681d2e07e324And I'm facing a strange problem: the sound is very bad with this one. It's noisy and with lots of artefacts. Everything is working perfectly on the Uno board, sound clear and very interesting. On my board with the same microcontroller it's awful. I've made lots of tests for now: - Directly on the Atmega pin : same result, very bad sound. - Exchanging the Atmega between my board and the Uno board: no changes. So it's not a problem from the µC itself. - The power comes from the master module and it seems as good as possible The only hardware difference between the Uno board and my reduced implementation is the frequency generator. I'm using a Ceramic resonator instead of a crystal oscillator. Does anyone have some experience with this kind of issue? do you think the resonator could generate some issues with the mozzi library ? If the resonator is not running at the expected frequency then I might expect some potentially harsh sounds; I don't know whether you have to program the chip differently when using a resonator vs. crystal... For mega328 things i usually use a crystal, and for ATTiny things I use the internal clock, so I've no experience with resonators in this case, sorry! |
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Post by pt3r on Oct 10, 2021 15:58:03 GMT
AFAIK resonators are more prone to cause possible issues with the ATmega chips, at least that's what I was told back in the days when I built my own arduino clone.
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Post by m4vrick on Oct 12, 2021 8:42:25 GMT
Thanks for you advices guys  I think I can't do anything else than a new revision for the PCB and changing the resonator for a crystal oscillator and adding decoupling capacitor around the Atmega. It's the two main differences between my board and a regular Uno board. |
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namke
wonkystuff
electronics and sound, what's not to like?!
Posts: 654
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Post by namke on Oct 12, 2021 10:25:30 GMT
I just took a look at the ATmega328P datasheet and it looks like a resonator needs more 'startup time' than a crystal (Page 28 of ATmega328P data says +4.1 or +65 ms), so perhaps this is something to consider? In that same table there is a column about clock-register values (CKSEL0 and SUT1..0). This might be configurable in the Arduino settings menu? Another alternative would be to try the internal RC oscillator (not as stable perhaps, but this won't be affected by the external crystal/resonator) - although this will only run at 8MHz it seems (section 8.6 of the datasheet) Wishing you luck! It would be nice not to have to re-run the PCB (See also things like this: ATmega328p, converting to internal clock from 16MHz) |
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namke
wonkystuff
electronics and sound, what's not to like?!
Posts: 654
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Post by namke on Oct 12, 2021 10:29:38 GMT
... the register values that I referred to above are actually 'fuse values' it seems, so this will be updated as part of the 'burn bootloader' task in the Arduino IDE ( see here) |
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Post by m4vrick on Oct 12, 2021 11:45:14 GMT
I really think the issue is around the clock and supply voltage. The Chord sketch is pushing the mozzi library very far so timing is critical and audio artefact is more likely to come from a lack of it. Fortunalty (more or less) I had issues with the first batch of PCB and I have a store credit so the new PCBs will be 'free'. And I hope this will be the final revision. |
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Post by girault on Oct 13, 2021 11:59:02 GMT
Finaly received to good PCB and builded the first proto. And here is the sound of this module : How does is sounds for you? interesting ? I like what I hear |
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Post by m4vrick on Oct 26, 2021 11:38:24 GMT
Here they are ! New version of the PCB, and I hope the last one.  |
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Post by m4vrick on Oct 26, 2021 20:17:16 GMT
and ... it's another fail.
Still have lots of artifact in output sound, can't figure out where is the issue. It's working perfectly on the Uno board, but not on mine.
It's not on the output filters as the artifacts are already there on the Atmega pin before the filters.
It's not the timing, I'm using a crystal oscillator like on the Uno board.
I guess it's not the power supply, I'm using the same for the Uno board.
Already tried to exchange the working Atmega on the Uno board with one I bought, in case I had fake ones or bad quality despite I got them from a good shop.
any ideas guys ?
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I have 4 big mistake and I need to order new revision of PCB.
