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| rnd:projects:euromidi [2023-05-07 02:54] – asdf | rnd:projects:euromidi [2023-09-10 17:51] (current) – [Resources] asdf |
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| ==== Eurorack voltages ==== | ==== Eurorack voltages ==== |
| Eurorack voltages are generally 10 Vpp, typically 0--10 V for unipolar signals and -5--5 V for bipolar signals. 0--5 V should be sufficient for pitch CV, as that range will grant a 5-octave spread. Gate signals will need to be higher. A gain of around 3 is required to bring the microcontroller's 3.3 V logic up to a usable level. | Eurorack voltages are generally 10 Vpp, typically 0--10 V for unipolar signals and -5--5 V for bipolar signals. 0--5 V should be sufficient for pitch CV, as that range will grant a 5-octave spread. Gate signals will need to be higher. A gain of around 3 is required to bring the microcontroller's 3.3 V logic up to a usable level. An even better idea would be to use a comparator (with a threshold of 2 V or so) to drive the gate outputs to 10 V. |
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| The VCV docs contain a section on [[https://vcvrack.com/manual/VoltageStandards#Pitch-and-Frequencies|converting between frequencies and voltages]] in the 1 V/Oct standard; the basic formula is $f=f_0\cdot 2^V\implies V=\log_2\left(\frac{f}{f_0}\right)$, where $f_0$ is the reference frequency. This should default to C4, or 261.6256 Hz. [[https://newt.phys.unsw.edu.au/jw/notes.html|This page]] includes information on converting note names to frequencies to MIDI notes. | The VCV docs contain a section on [[https://vcvrack.com/manual/VoltageStandards#Pitch-and-Frequencies|converting between frequencies and voltages]] in the 1 V/Oct standard; the basic formula is $f=f_0\cdot 2^V\implies V=\log_2\left(\frac{f}{f_0}\right)$, where $f_0$ is the reference frequency. This should default to C4, or 261.6256 Hz. [[https://newt.phys.unsw.edu.au/jw/notes.html|This page]] includes information on converting note names to frequencies to MIDI notes. |
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| Special attention must be paid to the power header. Since we're working with unipolar voltages, we should only need the +12 V line. | Special attention must be paid to the power header. Since we're working with unipolar voltages, we should only need the +12 V line. **Be sure to clearly identify the -12 V side!** |
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| {{ https://division-6.com/media/featured-eurorack-power.gif }} | {{ https://division-6.com/media/featured-eurorack-power.gif }} |
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| Unfortunately, all the quad DACs I've seen are SMD. | Unfortunately, all the quad DACs I've seen are SMD. |
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| | ==== User interface ==== |
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| ===== Prototyping ===== | ===== Prototyping ===== |
| * Teensy | * Teensy |
| * [[https://www.adafruit.com/product/4470|MCP4728 breakout]] | * [[https://www.adafruit.com/product/4470|MCP4728 breakout]] |
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| | ===== Resources ===== |
| | * [[https://github.com/pichenettes/eurorack]]: design files for Mutable Instruments modules; the schematics for [[https://pichenettes.github.io/mutable-instruments-documentation/modules/branches/downloads/branches_v40.pdf|Branches]] and [[https://pichenettes.github.io/mutable-instruments-documentation/modules/yarns/downloads/yarns_v03.pdf|Yarns]] are particularly illustrative for this project |
| | * [[https://playground.arduino.cc/Main/InterfacingWithHardware/#ui]] |
| | * [[https://code.google.com/archive/p/m2tklib/]] |
| | * [[https://github.com/Spirik/GEM]] |
| | * [[https://github.com/olikraus/U8g2_Arduino]] |
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| {{tag>eurorack electronics midi}} | {{tag>eurorack electronics midi}} |