3 ms·

And here's a MIDI-to-CV controller built with a $3 microcontroller instead of a $40 computer: https://github.com/elkayem/midi2cv https://github.com/elkayem/midi

And here's a MIDI-to-CV controller built with a $3 microcontroller instead of a $40 computer: https://github.com/elkayem/midi2cv https://github.com/elkayem/midi2cv

monocasa 6y ago
I'm not sure that has the automatic feedback system to calibrate voltage to note on arbitrary synths like is the bulk of the work listed in the article.
- kennywinker 6y ago
  this is the real win they got from using a raspberry pi - they could throw a cheap usb audio interface on it and get a feedback system. They could, of course, have done this using an ADC on a cheaper microcontroller - but it would have been a lot more coding to write the audio input and calibration from scratch.
XMPPwocky 6y ago
An Arduino Nano? What a waste... Just use a PIC or an ATTiny. Spending even $1 for something so simple is unnecessary. For personal projects, it's not often the case that you need to get BOM cost as low as possible and disregard other factors (like debuggability, or having enough DSP available to run the FFT for tuning calibration (though I suspect they'd be better off with autocorrelation...), or room for future expansion (adding multiple channels, adding a sequencer, adding control over the filter, implementing envelopes, running the Pi's audio output through the filter too...) Plus, they might have had the Pi before, and still have it afterwards. That's the nice thing about general-purpose computers- you can put a whole bunch of different software on them, and then switching between uses just involves moving the board itself and plugging cables in.
- deleted 6y ago
  [deleted]
- ChickeNES 6y ago
  I remember when I built my Minimoog clone in highschool I had to not only etch and drill a board for the midi2cv convertor, but also one for a parallel port PIC programmer to program the PIC it required. I think the parts for the two together would be around $100 adjusting for 15 years of inflation (of course, that was dwarfed by the parts cost for the synth).
- ssalazar 6y ago
  One functional advantage of a microcontroller over a single-board computer is lower latency due to not having the overhead of an operating system. Also, the Pi's built-in audio output is basically unusable, but easily replaced. However if you dont have floating point arithmetic like many microcontrollers, fixed-point DSP for FFT or autocorrelation presents its own set of challenges, which can be either a good thing or a bad thing.
qrv3w 6y ago
I get that my solution is a little more expensive. But, actually the whole thing costs ~$25, not $40, if you buy the three components thriftly (used Pi ~$15, usb audio adapter $5, mcp4725 $5). In contrast, that link you mentioned has over 15 parts instead of 3 parts, and it needs to be on a PCB/breadboard. The total cost is cheaper (probably $10 if your thrifty) but requires way more effort IMO than using a Pi. Crucially, I've never seen any MIDI to CV that provides a method for automatic tuning which is very time consuming. Using a Pi provides that easily and automatically with sox.
tessierashpool 6y ago
My suspicion is you didn't read the article, because the README for this otherwise quite awesome-looking project doesn't mention anything about doing FFTs on a $3 microcontroller, like the article author did on their Pi. Then again, if I missed it and you can do those FFTs with this project, that's pretty cool.
jacquesm 6y ago
That's actually not an equivalent. If you're going to bitch and try to diminish someone's achievement then at least do them the favor of reading the article and understanding what makes it unique.
- daneel_w 6y ago
  There was no bitching or diminishing intended, you have completely misread me.

And here's a MIDI-to-CV controller built with a $3 microcontroller instead of a $40 computer: https://github.com/elkayem/midi2cv https://github.com/elkayem/midi2cv

monocasa 6y ago

I'm not sure that has the automatic feedback system to calibrate voltage to note on arbitrary synths like is the bulk of the work listed in the article.

kennywinker 6y ago
this is the real win they got from using a raspberry pi - they could throw a cheap usb audio interface on it and get a feedback system. They could, of course, have done this using an ADC on a cheaper microcontroller - but it would have been a lot more coding to write the audio input and calibration from scratch.

XMPPwocky 6y ago

An Arduino Nano? What a waste... Just use a PIC or an ATTiny. Spending even $1 for something so simple is unnecessary. For personal projects, it's not often the case that you need to get BOM cost as low as possible and disregard other factors (like debuggability, or having enough DSP available to run the FFT for tuning calibration (though I suspect they'd be better off with autocorrelation...), or room for future expansion (adding multiple channels, adding a sequencer, adding control over the filter, implementing envelopes, running the Pi's audio output through the filter too...) Plus, they might have had the Pi before, and still have it afterwards. That's the nice thing about general-purpose computers- you can put a whole bunch of different software on them, and then switching between uses just involves moving the board itself and plugging cables in.

deleted 6y ago
[deleted]
ChickeNES 6y ago
I remember when I built my Minimoog clone in highschool I had to not only etch and drill a board for the midi2cv convertor, but also one for a parallel port PIC programmer to program the PIC it required. I think the parts for the two together would be around $100 adjusting for 15 years of inflation (of course, that was dwarfed by the parts cost for the synth).
ssalazar 6y ago
One functional advantage of a microcontroller over a single-board computer is lower latency due to not having the overhead of an operating system. Also, the Pi's built-in audio output is basically unusable, but easily replaced. However if you dont have floating point arithmetic like many microcontrollers, fixed-point DSP for FFT or autocorrelation presents its own set of challenges, which can be either a good thing or a bad thing.

qrv3w 6y ago

I get that my solution is a little more expensive. But, actually the whole thing costs ~$25, not $40, if you buy the three components thriftly (used Pi ~$15, usb audio adapter $5, mcp4725 $5). In contrast, that link you mentioned has over 15 parts instead of 3 parts, and it needs to be on a PCB/breadboard. The total cost is cheaper (probably $10 if your thrifty) but requires way more effort IMO than using a Pi. Crucially, I've never seen any MIDI to CV that provides a method for automatic tuning which is very time consuming. Using a Pi provides that easily and automatically with sox.

tessierashpool 6y ago

My suspicion is you didn't read the article, because the README for this otherwise quite awesome-looking project doesn't mention anything about doing FFTs on a $3 microcontroller, like the article author did on their Pi. Then again, if I missed it and you can do those FFTs with this project, that's pretty cool.

jacquesm 6y ago

That's actually not an equivalent. If you're going to bitch and try to diminish someone's achievement then at least do them the favor of reading the article and understanding what makes it unique.

daneel_w 6y ago
There was no bitching or diminishing intended, you have completely misread me.