||[Build Thread] Arduino based String Machine
| br>Hi everyone,
as announced here, I'm giving this little device published in these two blogs...
... a chance. I'm adding the LPF described in the second one, and will also include a MIDI-In jack so I can sequence it. Hopefully, since I have absolutely no programming skills whatsoever and must rely on the sourcecode as published in Jan Ostman's blog.
Anyway - the total (!) costs come up to about 40 Euros or slightly less, so there's not too much risk should I fail .
I got a good-as-new Garagekeys Mini for about 15 or 16 Euros off German Ebay, took off the upper part of the case, and built a wooden case very similar to the one in the second blog mentioned above - the keys need to be removed for dismantling it, and I re-installed the outer ones so I coud properly fit the top cover a bit later on:
Since I didn't like the gaps between the lowest and highest keys and the wooden case, I made the top cover cover them:
Some support construction for the top cover (the wooden parts on the sides turned out to be impractical so I removed them again):
Inbetween doing the woodwork, I designed, etched, drilled and populated the PCB for the little LPF (the plastic pot will be replaced with an Alpha pot, however):
The upper part of the now keyless-for-mounting keyboard sitting in the painted case:
The keys are back in place:
And finally, that's how the top cover is placed. The 'gap' will be covered by an aluminum plate (cut to size and drilled yesterday).
| br>Dan Lavin
| br>Nice job! Excellent documentation of the mechanical parts of the build! br> br>
| br>Some update here as well .
The LPF and the output jack are mounted in the case:
The front panel - anodized sheet aluminum, and self-adhesive foil. It has to be assembled from two parts (the foil, that is) as the length exceeds ~ 30 cm/12 in.
I mounted the Arduino clone plus the opto coupler components on a small piece of perfboard to make handling easier. The keyboard connections are already made on this picture. I simply soldered them instead of using some connector:
At this point I'd like to point out that I encountered some problems in compiling the software: C&P from the PDF plus inserting the MIDI lines from Jan's site didn't work out. I was actually about to abandon the project since I have no programming skills nor knowledge whatsoever, making it impossible to fix any bugs. I was very lucky (and am so glad and thankful) someone on another forum helped me by fixing the file and providing it for me (thanks Lars and Jens!) .
Anyway, here's how the 3 "left" pots (the other two ones plus a bypass switch are connected to the LPF) are connected. I just attached a bit of cardboard to make handling easier again. The wipers of the pots go to the Arduino, the 'outer' connections go to 0 and + 5 V, respectively.
The little machine is mostly ready by now. I hope I'll have it finished by the end of the week. br> br>
| br>Can the keyboard size be extended I wonder ? br> br>
|Synesthesia wrote: |
|Can the keyboard size be extended I wonder ? |
I doubt it (at least with the software as is) since the software is kinda fine-tuned to that specific keyboard. Maybe someone with programming skills can adapt other keyboards ?
However, hopefully the MIDI in allows for an extended range (sequencer, external keyboard). br> br>
| br>I finished the build on Saturday .
I use a common 9V wall wart, from which I take the original 9V for the LP and (via a 7805) 5V for powering the Arduino clone:
Time for powering it up, connecting it to my little practise amp I always keep near my workbench, and to my utter amazement the thing actually works .
OK, that means mount the aluminum panel to the wooden cover part, put the pots and the switch in their positions, and place the upper panel on the boat:
Does it sound like a real Solina?
Nah, that'd be a bit too much to say. But considering the total costs of under € 40 (or $ 50) - which made it a no-brainer for me - it is definitely not bad, even without using the LPF (which I actually prefer at the moment). The three parameters regulated by the "original" pots do a nice and really effective job.
So, all in all: Not replacing an original 70s string machine, which easily costs 40 - 50 times as much. But still a nice gadget, and surely even more so when played through some big fat effect - I'll of course try it through the Oakley SRE330 once this one is finished .
Programming (or at least debugging) skills are certainly of advantage, as I pointed out before.
That's it from my side so far. br> br>
| br>Cool. I approve! br> br>
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