features (a lot of TODO's)::

• 7 segment display to show current "program"
• 8x8 LED matrix to show settings and animations
• 2 rotary encoders to change settings
• 3 footswitches: turn effect on/off, change program up/down
• use of an external audio interface (I use a Focusrite 2i2)
• expression pedal

• raspberry pi rev b

• Adafruit blue 7 segment display (address set to 0x74 by shorting A2)

• Adafruit 8x8 LED display (address 0x70)

• mcp3008 chip for the expression pedal

• focusrite scarlett 2i2

• m-audio uno

WiringPi has its own numbering scheme. Let's see what's what.

mcp3008::

exp. pedals::

• • to pin 15 of mcp3008
• • to ground

• switches: one side to ground, other side to given pin.

• displays: 2 i2c pins to raspberry pi header, and ground and 3.3v

Neuktrik NAUSB-W

See::

http://learn.adafruit.com/matrix-7-segment-led-backpack-with-the-raspberry-pi/hooking-everything-up

d and c are in parallel for the 2 displays.

• install raspbian wheezy on an SD card (I used 2013-09-25-wheezy-raspbian)

http://www.raspberrypi.org/downloads

• git clone https://github.com/jackha/raspberry-stomp

• overclock /boot/config.txt

http://wiki.linuxaudio.org/wiki/raspberrypi

arm_freq=800 core_freq=350 sdram_freq=500 gpu_mem=16

Add audio repository::

wget -O - http://rpi.autostatic.com/autostatic.gpg.key| sudo apt-key add - sudo wget -O /etc/apt/sources.list.d/autostatic-audio-raspbian.list http://rpi.autostatic.com/autostatic-audio-raspbian.list sudo apt-get update

Install JACK (there is also a JACK2, for us it's no difference)

$ sudo apt-get --no-install-recommends install jackd1

• enable i2c communication

  $ sudo nano /etc/modules

add 2 lines::

• i2c-bcm2708

• i2c-dev

  $ sudo apt-get install python-smbus

Remove i2c devices from the blacklist::

$ sudo nano /etc/modprobe.d/raspi-blacklist.conf

Comment out lines by placing a '#' before it::

check if displays are OK::

$ sudo i2cdetect -y 1

Should display 70 and 74 somewhere

Setting permissions for the i2c devices::

$ sudo nano /lib/udev/rules.d/60-i2c-tools.rules 

change 0x660 to 0x666

After reboot it should display::

$ ls -al /dev/i2c-*

crw-rw-rwT 1 root i2c 89, 0 Oct 27 13:08 /dev/i2c-0 crw-rw-rwT 1 root i2c 89, 1 Oct 27 13:08 /dev/i2c-1

Now you can interact with the displays without being superuser.

We use the rotary encoder library from gaugette, which in turn uses wiringPi and WiringPi2::

$ sudo apt-get install python-dev python-setuptools

Modules that use GPIO require wiringpi and WiringPi2-Python.

To install wiringpi:

git clone git://git.drogon.net/wiringPi
cd wiringPi
sudo ./build

To install wiringpi2-python:

git clone https://github.com/Gadgetoid/WiringPi2-Python.git
cd WiringPi2-Python/
sudo python setup.py install
cd ..

trying this::

$ sudo apt-get install python-rpi.gpio 

https://code.google.com/p/raspberry-gpio-python/wiki/Examples

See if it is listed::

$ cat /proc/asound/cards 0 [ALSA ]: BRCM bcm2835 ALSbcm2835 ALSA - bcm2835 ALSA bcm2835 ALSA 1 [USB ]: USB-Audio - Scarlett 2i2 USB Focusrite Scarlett 2i2 USB at usb-bcm2708_usb-1.3, high speed

Set the Alsa USB audio device to have priority 0::

# sudo nano /etc/modprobe.d/alsa-base.conf

Change the line with snd-usb-audio to::

options snd-usb-audio index=0

$ speaker-test -c2 -D hw:0,0 -F S32_LE

(somehow only the sample format S32_LE works...)

For my M-audio Uno we need::

$ sudo apt-get install midisport-firmware 

Mcp3008

$ sudo easy_install rpi.gpio

Automatically startup and shut down::

$ copy boot.sh /boot

Add /boot/boot.sh to /etc/rc.local

If anything goes wrong in jackstart.sh, you can edit boot.sh from your windows/mac computer without mounting the ext4 volume. Yaay! (I got experience...)

I used overclocking to make the pi snappier and to make some patches work at all.

#arm_freq=900 #core_freq=350 #sdram_freq=500

force_turbo=1

arm_freq=1000 gpu_freq=350 core_freq=500 sdram_freq=500 over_voltage=6 gpu_mem=16

Started as a fork of::

Adafruit's Raspberry-Pi Python Code Library https://github.com/adafruit/Adafruit-Raspberry-Pi-Python-Code.git

Rotary encoder code from gaugette::

https://github.com/guyc/py-gaugette/blob/master/gaugette/rotary_encoder.py