Nurdspace eurorack raspberry pi hat: Difference between revisions

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=== specifications ===
=== specifications ===


The title says it all.
This will be an interface between [[eurorack]] signals ("control voltage" and "gates") and a raspberry pi (a "hat"). For that, the hat will have an ADC and a DAC (multichannel) connected via SPI (multichannel and not multiple devices as the rpi has only 2 SPI channels).
 


==== First version ====
==== First version ====
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* PDF of revision 001: [[File:001.pdf]]
* PDF of revision 001: [[File:001.pdf]]
=== to do ===
* double check 3.3V power consumption of parts
* check if a MCP6001 opamp can withstand not only -5/+5 but also -12/+12V





Revision as of 20:58, 15 July 2022

Eurocrack-hat
Nurd-euro-pi.jpg
Participants
Skills Electronics, Programming
Status Active
Niche Music
Purpose Fun
Tool No
Location
Cost
Tool category Electronics,Eurorack

Eurocrack-hat

Nurd-euro-pi.jpg {{#if:No | [[Tool Owner::{{{ProjectParticipants}}} | }} {{#if:No | [[Tool Cost::{{{Cost}}} | }}


specifications

This will be an interface between eurorack signals ("control voltage" and "gates") and a raspberry pi (a "hat"). For that, the hat will have an ADC and a DAC (multichannel) connected via SPI (multichannel and not multiple devices as the rpi has only 2 SPI channels).


First version

  • 2x analogue in (10 bit resolution, MCP3008, 0.5mA max power consumption )
  • 2x analogue out (12 bit resolution, MCP4922, 0.7mA max power consumption )
  • 2x gate in
  • being able to also run without a real eurorack powersupply (it produces its own -5V by using an ICL7660)
  • based oninspired on https://micro-twin.com/hardware.php

Second version

  • more analogue in, 12 bit resolution by using a MCP3204 or MCP3208 or so?
  • more analogue out, gates in
  • also gates out
  • LEDs for gate status
  • pins for neopixel connection (gnd + signal)
  • I2C breakout (for e.g. small displays)
  • SPI extender? (does something like that exist?)
  • SMD technology maybe?

schematics


to do

  • double check 3.3V power consumption of parts
  • check if a MCP6001 opamp can withstand not only -5/+5 but also -12/+12V


0...3.3V to -5/+5V

falstad circuitjs simulation

The opamp needs +5 and -5 for power.

calculated with https://masteringelectronicsdesign.com/differential-amplifier-calculator-2/

Circuit-20220715-2051.png


-5/+5V to 0...3.3V

falstad circuitjs simulation

The opamp needs +3.3V and 0V for power.

Circuit-20220709-1750.png


software

  • I've chosen a DAC and ADC with SPI to easily connect them to a raspberry pi.
  • gate signals can be toggled via e.g. wiringpi