jorgevelez / ports

Ports is an OSC to CV/Gate and MIDI converter. Built to run on raspberry pi zero w (or other variants), using max11300 chip over SPI.

Ports

Ports is an OSC to CV/Gate and MIDI converter. Built to run on raspberry pi zero w (or other raspberry pi variants). It listens for incoming OSC messages on port 5000.

It will convert them into CV/Trigger and gate on the MAX11300 chip or MIDI messages (see API section of this readme)

Installation

During this procedure we assume that you have access to your pi, using a screen + keyboard, or over SSH.

get your raspberry pi setup:

• download the raspbian lite image. you only need the lite version (no need for X windows and similar things) https://www.raspberrypi.org/downloads/raspbian
• Install raspbian on your pi. https://www.raspberrypi.org/documentation/installation/installing-images/
• Enable sshd by putting an empty file called ssh on the boot partition. touch /Volumes/boot/ssh on mac.
• get your pi connected on the internet
  • use a wired ethernet connection. just plug the pi into your router.
  • or setup wifi as described https://www.raspberrypi.org/documentation/configuration/wireless/wireless-cli.md

Ports could work on other linux flavours such as osmc etc, but the automatic WLAN fallback might not work as expected as WLAN is distro specific.

/install.sh (below) assumes the system is a raspbian jessie.

install ports

Clone ports repository git clone https://github.com/hdavid/ports.git

• if git is not installed, just run sudo apt-get update && sudo apt-get install git

Then from the ports directory run ./install.sh

This will:

• download and install the SPI broadcom drivers
• install liblo osc lib package
• install dnsmsaq package (dns, dhcp for accesspoint mode)
• compile ports
• configure fall back access point ssid: ports, psk: portsports
• configure ports to start at boot time automatically

you can also install pink, to provide ableton link. run ./install-pink.sh

Accessing

If no known wifi network is in range, ports will create an access point :

• ssid: ports
• psk: portsports

You can add your own wifi networks in /etc/wpa_supplicant/wpa_supplicant.conf. Make sure to enter your network before the one added by ports (identified by ssid="ports" and mode=2), as wpa_supplicant try the networks in the order they appear in this configuration file.

Example of network configuration :

network={
	str_id="myNetworkFriendlyName"
    ssid="myNetwork"
    psk="MyPassword"
}

Running

Port must run as root on order to access SPI bus used to communicate with the MAX11300. Note that ports is started automatically at boot time. (done by ./install.sh)

you can however start manually from

sudo /usr/local/bin/portsd no-daemon

OSC API

OSC Port: 5000

CV Outputs

/out/<[1-20]>/<mode> <float>

mode is one of : trig, gate, flipflop, cvuni, cvbi, lfosine, lfosaw, lfotri, lfosquare

unipolar is [0v 10v]. bipolar is [-5v +5v]. LFO rates are in Hertz. other input values are in the range [0 1] and mapped to the cv voltage.

MIDI Output

for now the MIDI device is hardcoded in the code to be the first usb device plugged. /dev/snd/midiC1D0 is easily changeable in Ports.cpp.

/midi/<channel>/cc/<midiCC> <value>

/midi/<channel>/noteOn/<noteNumber> <velocity>

/midi/<channel>/noteOff/<noteNumber> <velocity>

channel: 1-16

noteNumber, midiCC, velocity, value : 1-127

Possible Improvements

• mdns http://avahi.org/doxygen/html/client-publish-service_8c-example.html
• web server : https://github.com/cesanta/mongoose
• Ableton link : https://github.com/shaduzlabs/pink-0 http://shaduzlabs.com/blog/23/pink0-an-ableton-link-to-clockreset-hardware-converter.html