Table of Contents
Raspi Bit
A Raspberry Pi Zero board for the Paper-Bits to rule all GPIOs in Pure Data.
Schematic
change the PWM audio pins
https://www.raspberrypi.org/documentation/configuration/pin-configuration.md
https://www.raspberrypi.org/forums/viewtopic.php?f=91&t=86609
https://www.raspberrypi.org/forums/viewtopic.php?f=44&t=39138
Or like on https://othermod.com/raspberry-pi-zero-audio-circuit/
Open:
$ sudo nano /boot/config.txt
Add:
dtoverlay=pwm-2chan,pin=18,func=2,pin2=13,func2=4
DAC
DAC0808: http://www.ti.com/lit/ds/symlink/dac0808.pdf
MC1408: http://pdf.datasheetcatalog.com/datasheet/philips/MC1408-8_3.pdf
Example: https://people.ece.cornell.edu/land/courses/ece4760/FinalProjects/s2003/gsh7/ECE476/archive.htm
Negative Voltage Source
https://www.allaboutcircuits.com/projects/build-your-own-negative-voltage-generator/
http://www.stephenhobley.com/blog/2011/03/28/creating-a-negative-voltage-from-a-positive-one/
Pure Data
PD WiringPi:
http://dernulleffekt.de/doku.php?id=puredata:gpio