Took me a couple of days to figure out the layout. This is going to be based on Arduino Mega (embed version), with 8 footswitches, 8 leds, 6 pots, 3 inputs for expresison pedals, and one encoder.
Gonna try it out on the cnc soon. This will be my first handmade double-sided pcb. Wish me luck guys
…more of a sidenote. As I said below in the comments, I’ve built two analog expression pedals in the aluminium chassis you can get on Aliexpress (God bless AliExpress!), based on the led-photoresistor pair. These are going to be used with the CC device I’m building. The pedals work quite smoothly with the CC device prototype and the MOD Dwarf, controlling plugins like volume and filters. I’ve just been soundscaping, totally lost track of time…
Folllowing the fantasy naming convention of the Dwarf, I’m going to call these ‘kobolds’, and the CC device itself an ‘Elf’, I guess.
@spunktsch, sure, once I have actually built it. I’m still not sure if I can pull this off - the trickiest part, I guess, would be milling an aluminium enclosure box on a cheap cnc machine from AliExpress…
@jon By the way, compliments to your hardware designers, the way they have designed the pin assignments of the ControlChain RJ45 connectors! Routing those was no mean feat: the traces were literally tying themselves in knots
On this, at this point, I’m personally a bit outdated on the status, yet I know that the plan is to move on with this side by side with the expression pedal release. Yet I can’t tell you exactly when that will happen.
Are you going to publish the hw design of the exp pedal, like, on a Git Hub maybe? I’m curious what hw solution you went with. I’m almost finished building an exp pedal (a regular one, not CC-type) based on a photoresistor, because the usual gear-type transmission of a pedal motion to a pot doesn’t allow for full rotation of a pot’s knob, hence the output voltage range is limited, and I don’t know how to bypass that limitation, except for using the pots with narrower rotation angle. So I wonder what kind of solutions the pros are using.
Photoresistor still does not give a full range of voltage (clean 0V to 5V, or 0.0 to 1.0 on an Arduino’s analog input) but at least I get 0.6 to 0.89, and that’s something.
Well, I don’t see any other option to make a square shape for a 20x4 LCD other than lots of drilling and filing, and that usually turns out rather ugly.
Also drilling 18mm holes for rj45 connectors can also be tricky, I don’t have a drilling station for that.
I’ve got a couple of smaller but similarly thick enclosures and a few spare milling bits to practice XD
Thanks for the info! If the design is not open, I’ll just have to buy it and reverse-engineer it
As I said, from what I’ve seen (not much though) usually gear-type transmission in a pedal does not give that 270-degree full spin that a usual pot requires to produce all range of voltages (zero to whatever’s in the circuit), so it’s either a special pot that gives a full range of voltages at, say, 180 degrees turn, or some way of compensating for it electronically, which I can’t figure out how to do 'cos I’m not that qualified.
Do you have e any other machines like a laser cutter or 3D printer? Does it need to be aluminium? Another option is folded sheet metal. If you can design it in can you can get it made as a one off through companies like 3D hubs
I only do the mechanical design so I can’t speak on this 100% but maybe @Jan can confirm. The way I understand it is like this. I think the control signal is digital, so you have a calibration mode where you tilt the pedal back and set the zero point at whatever voltage that is, then tilt it all the way forward and set the 100% point at whatever that voltage is. Then it just interpolates the 0-100 values between those 2 voltages. As I said, I’m not the electrical engineer so I’m just guessing here
Of course, this makes things easier; but I’m building (actually, already built) a couple of analog expression pedals. Indeed, digital calibration happens later on a CC device (that is on a breadboard yet), despite the fact that I get 0,3V-4,55V range out of a max 0,0-5,0V range (not bad huh) with a LED-photoresistor pair. Yet, call me crazy, but I still want to make the design as clean as possible without additional crutches like calibration.
No, I have no 3D priner (as much as I want one, my wife will kick me out of the house if I bring in another machine ). I want to use the device in a pedalboard in a real gig environment, hard stomping is expected, so plastic is not an option. Sheet metal would do, but it can be quite expensive for a single piece order (I have no plan for mass-production to enjoy economy of scale). I’ll give it a shot with aluminium: the enclosures are already on the workbench, it would be a waste not to try.
As for the laser cutter - my cnc machine came with a laser but I hardly think it is powerful enough to cut through 2mm aluminium.
In my experience (and I’ve used a few 3d printed on stage and band rehearsals) they are very durable - even when only using PLA and a non strength optimized (but still purposely constructed) enclosures. Plus when something breaks i’ll just print a new one. But I don’t know if its worth the the trouble with you wife.
I’m just thinking if you are going to cnc mill it from a big block if aluminium that will be pretty expensive. You could also cnc mill it from a strong plastic that is easy to mill like HDPE for example. With a laser cutter you could cut acrylic or something. A folded sheet metal enclosure might only be 50-100 euro as a one off which is not too bad considering the time saved
Hang on, I see where the confusion is coming from: I’m not milling a solid block of aluminium, that would be a waste indeed. I’ve got one of those aluminium boxes they sell on Aliexpress, and I’m just going to mill all the mounting holes in it!