rpi audio codec

here's how to set up the proto WM8731 based audio codec module from MikroElektronika and use it with supercollider on a raspberry pi 3.

power off the rpi and connect the proto board to the rpi with jump wires like this...

proto               raspberry
-----                -----
sck           ->    rpi 12
miso         ->    rpi 38
mosi         ->    rpi 40
adcl+dacl  ->    rpi 35  //both proto pins go to the same rpi pin
sda           ->    rpi 3
scl            ->    rpi 5
3.3v         ->    rpi 1
gnd          ->    rpi 6

see pinout diagram for help with the rpi gpio numbering.

power on the rpi and open a terminal and type...

sudo nano /boot/config.txt

find and uncomment the first line and add the second...


press ctrl+o to save and ctrl+x to exit.

sudo reboot

again open a terminal and type...


first press F5 to show all controls, then...
* enable item 'Mic' (space)
* set item 'Mic Boost' to 100 (up arrow key)
* enable item 'Playback Deemphasis' (m key)
* disable item 'ADC High Pass Filter' (m key)
* set item 'Input Mux' to Mic (arrow keys)
* enable item 'Output Mixer HiFi' (m key)


now you should be able to start jackd with for example...

jackd -P75 -dalsa -dhw:0 -r48000 -p256 -n2

and get decent in/out sound at 5.3ms jack latency.

Image icon alsamixer-proto.png126.01 KB

solar powered supercollider

here's how to run supercollider on power coming from the sun...

the main component is a raspberry pi zero with wifi that at startup creates a wireless access point, starts jackd+supercollider and launches a default sound patch.
to play around with the system and change the default sound log on to the access point with a laptop and start livecoding supercollider via the terminal or use the standard scide via vnc. one can for example also set up a couple of osc responders and let friends log on with their phones to control sounds.



the connections are pretty straightforward...

solarpanel -> dcdc converter -> battery -> rpi0 -> soundcard -> amplifier -> speaker(s)

the dcdc converter is taking the higher voltage coming out of the solar panel (~6v) and turns it into a stable 5v. this is then either charging the battery, or directly powering the raspberry pi. note that the amplifier also needs 5v and here i have taken that from pins 4 and 6 on the pi.

the powerbank battery is optional and can be omitted but then the solar panel will have to stay in the sun at all times - else the system will turn off or reboot when the power from the panel drops. the battery acts like a reservoir for when clouds are passing by but not only that - it also lets the system be used for a couple of hours in the evening.

material/modules needed:

* rpi zero w
* 8gb micro sd card
* 5v usb powerbank (best if it can charge and output power at the same time)
* 6v 6watt solar panel ( www.adafruit.com/product/1525 )
* dc-dc converter ( www.olimex.com/Products/Power/DCDC6-16-TO5 )
* usb sound adapter
* pam8403 stereo amplifier module
* two full range speakers
* wooden board, double adhesive tape + various cables and screws

download raspbian jessie (here jessie desktop 2017-07-05-raspbian-jessie.zip) and burn it onto the sd card with etcher.

do the usual setup (change default password, activate ssh), optionally activate vnc and then install supercolliderStandaloneRPI1.

to set up a wifi access point do the following (basically the same as this)...

* sudo apt-get install dnsmasq hostapd
* sudo systemctl stop dnsmasq
* sudo systemctl stop hostapd
* sudo nano /etc/dhcpcd.conf  #and add...
        denyinterfaces wlan0
* sudo nano /etc/network/interfaces  #and make sure wlan0 looks like...
        allow-hotplug wlan0
        iface wlan0 inet static
* sudo service dhcpcd restart
* sudo ifdown wlan0
* sudo ifup wlan0
* sudo nano /etc/dnsmasq.conf  #and add the following...
* sudo nano /etc/hostapd/hostapd.conf  #and add the following...
* sudo nano /etc/default/hostapd  #and change to the following...
* sudo service hostapd start
* sudo service dnsmasq start

last change the file mycode.scd and add this default sound (tweet0340)...

        play{a=SinOscFB;Mix(AllpassN ar:a.ar(midicps(Duty.ar(c=a.ar(1/[12,8])+3/24,0,Dseq([0,8,5,1,5,4,5]*round(c*18),inf))+60),c*2)/4)}// #SuperCollider

if it is distorting try lowering the volume in alsamixer.


after many years i finally got around to rebuild one of these boxes.

so this old soviet made device is now a wireless controller that send out osc. there are in total 34 buttons, 16 knobs and an additional rgb status led. it automatically connects via wifi to max or supercollider and run on 5v (usb powerbank).

kicad schematics, arduino firmware, supercollider classes and maxmsp abstractions attached below.


the inside is quite a mess. i use an atmega168 together with six 4051 multiplexers to read all the inputs. the wifi module is an esp8266-01.


Package icon udssrKontroll_1.0.zip116.03 KB


this box can drive eight speakers (3watt each) and play soundfiles independently from eight micro sd cards (mp3 or wav). an arduino nano is programmed to do sequencing, randomise playback, control volume and set equaliser settings. it all runs on a single 9-12v power supply.


very cheap to build. the biggest cost are all the sd cards.

to send commands out to all eight mp3 players, i'm bit banging 9600 baud serial data out on eight digital pins.


here is another project built around the esp8266. it's a wireless osc controlled 100w led. as the led should act as a stroboscope and not be kept on for long durations of time, i could save space and cost using a smaller sized heatsink. via wifi (opensound control) the led can be turned on/off, the level, attack and release times adjusted etc. there is also a push button trigger input as well as a microphone input (both not connected in the picture). so the strobe can be triggered manually by the musician, by the sound of the nearby instrument or remotely by a computer.

the strobe also send out osc data from the button and mic so it can in turn be used to trigger additional sounds in the computer.

supercollider example code...


n= NetAddr("", 15555);
n.sendMsg(\led, 0.5, 0.1)   //val, fade
n.sendMsg(\led, 0.0, 0.01)  //val, fade
n.sendMsg(\micMode, 1);  //mic on/off
n.sendMsg(\micFade, 1.0, 0.1);  //mic atk rel
n.sendMsg(\butFade, 1.0, 0.1);  //but atk rel

OSCdef(\oscin, {|msg| msg.postln}, \f0led, NetAddr("", 15555));

f0led 1

the battery is a 12v sealed lead-acid and i measured up toward 8 amps current draw. it weights about 0.5kg.

f0led schematics

bill of material...

1       ESP8266-01
1       4x2 socket
1       heatsink
2       100uF cap
1       100 resistor
1       10k resistor
1       10k log pot     (reichelt ACP 6-L 10K)
1       regulator       (reichelt LF 33 CV)
1       mosfet          (reichelt IRLZ 34N)
1       mic             (reichelt MCE 101)
4       screwterminals  (reichelt AKL 101-02)
1       12v lead-acid   (pollin 94‑271194)
1       heatsink        (ebay 2.4x2.4inch Aluminum Alloy Heat Sink for 1W/3W/5W/10W LED Silver White)
1       dcdc            (ebay DC DC boost converter Constant Current Mobile Power supply 250W)
1       100w led        (ebay 100W Cool White High Power LED LIGHT SMD chip Panel 9000-10000LM)

thick wires
heat paste
screws and nuts

arduino code...

// * install OSC from https://github.com/CNMAT/OSC
// * edit where it says EDIT below
// * choose board: "Generic ESP8266 Module" 160 MHz

//TODO: gamma correction

#include <ESP8266WiFi.h>
#include <WiFiUdp.h>
#include <OSCMessage.h>
#include <OSCData.h>

//pin3 (urxd) can do pwm out
//pin2 and pin0 can not do pwm
//pin2 and pin0 have to be 3v3 at powerup

#define PINMIC 0
#define PINBUT 2
#define PINPWM 3
#define PORT 15555
#define UPDATERATE 16
#define PINGRATE 600

const char *ssid = "mywlan"; //EDIT your accessPoint network name
const char *password = "mypass";  //EDIT your password
const char *espname = "f0led";
const unsigned int outPort = 57120;
IPAddress outIp;
float micFadeAtk = 1.0, micFadeRel = 0.1; //default fade times
float butFadeAtk = 1.0, butFadeRel = 0.1; //default fade times
float val = 0.0, valTarget = 0.0, fade = 1.0;
unsigned long nextTime;
byte micMode = 0;  //allow mic trigger led on/off
byte micState = 1;
byte butState = 1;
int cnt;
WiFiUDP Udp;
OSCMessage msgPing("/f0led");
OSCMessage msgMic("/f0led");

void setup() {
  WiFi.begin(ssid, password);
  while (WiFi.status() != WL_CONNECTED) {
  outIp = WiFi.localIP();
  outIp[3] = 99;  //send to ip x.x.x.99 on same network (e.g.
  Serial.begin(115200, SERIAL_8N1, SERIAL_TX_ONLY);
  pinMode(PINMIC, INPUT);
  pinMode(PINPWM, OUTPUT);

void oscLed(OSCMessage &msg) {
  valTarget = msg.getFloat(0);
  fade = msg.getFloat(1);
void oscMicMode(OSCMessage &msg) {
  micMode = msg.getInt(0);
void oscMicFade(OSCMessage &msg) {
  micFadeAtk = msg.getFloat(0);
  micFadeRel = msg.getFloat(1);
void oscButFade(OSCMessage &msg) {
  butFadeAtk = msg.getFloat(0);
  butFadeRel = msg.getFloat(1);
void sendOscBut(byte val) {
  OSCMessage msg("/f0led");
  Udp.beginPacket(outIp, outPort);
void sendOscMic() {
  Udp.beginPacket(outIp, outPort);
void sendOscPing() {
  Udp.beginPacket(outIp, outPort);

void loop() {

  //--osc input
  OSCMessage oscMsg;
  int packetSize = Udp.parsePacket();
  if (packetSize) {
    while (packetSize--) {
    if (!oscMsg.hasError()) {
      oscMsg.dispatch("/led", oscLed);
      oscMsg.dispatch("/micMode", oscMicMode);
      oscMsg.dispatch("/micFade", oscMicFade);
      oscMsg.dispatch("/butFade", oscButFade);

  //--mic input
  if (digitalRead(PINMIC) == 0) {
    if (micState == 0) {
      micState = 1;

  if (millis() >= nextTime) {
    nextTime = millis() + UPDATERATE;
    if (cnt % PINGRATE == 0) {

    //--mic input2
    if (micState == 1) {
      micState = 2;
      if (micMode == 1) {
        valTarget = 1.0;
        fade = micFadeAtk;
    } else if (micState == 2) {
      if (digitalRead(PINMIC) == 1) {
        valTarget = 0.0;
        fade = micFadeRel;
        micState = 0;

    //--button input
    if (digitalRead(PINBUT) == 0) {
      if (butState == 0) {
        butState = 1;
        valTarget = 1.0;
        fade = butFadeAtk;
    } else {
      if (butState == 1) {
        butState = 0;
        valTarget = 0.0;
        fade = butFadeRel;

    //--fade in/out
    if (val < valTarget) {
      val = val + fade;
      if (val > valTarget) {
        val = valTarget;
    } else if (val > valTarget) {
      val = val - fade;
      if (val < valTarget) {
        val = valTarget;

    analogWrite(PINPWM, int(val * 1023));


here is how i build super cheap wireless osc controlled rgb ledstrips. the main components for these are an esp8266, a 5v powerbank, a voltage regulator and some leds. the leds i've used so far are the SK6812 RGBW, but it is easy to adapt the arduino code to work with other models like the WS2812B.

f0neo 1

f0neo 2

f0neo schematics

a basic version of the arduino code shown here below. when it starts it creates a soft access point. connect to it with a computer or phone, figure out the ip address of the esp8266 and start sending osc commands to it.

// * install OSC from https://github.com/CNMAT/OSC
// * install Adafruit_NeoPixel from library manager
// * edit where it says EDIT below
// * choose board: "Generic ESP8266 Module"
// * upload and connect to softap with laptop
// * try to send osc messages to ip port 19999
//protocol: [\rgbw, index, red, green, blue, white] example red: [\rgbw, 0, 255, 0, 0, 0]

#include <ESP8266WiFi.h>
#include <WiFiUdp.h>
#include <OSCMessage.h>
#include <OSCData.h>
#include <Adafruit_NeoPixel.h>

#define PORT 19999
#define NUMNEO 12  //EDIT number of neo pixels in use
#define PINNEO 2

const char *ssid = "f0neo"; //EDIT softAccessPoint network name
const char *password = "mypass";  //EDIT password

WiFiUDP Udp;

//EDIT to match type of leds (see example/Adafruit_NeoPixel/strandtest)
Adafruit_NeoPixel pixels = Adafruit_NeoPixel(NUMNEO, PINNEO, NEO_RGBW + NEO_KHZ800);

void setup() {
  WiFi.softAP(ssid, password);

void rgbw(OSCMessage &msg) {
  pixels.setPixelColor(msg.getInt(0), msg.getInt(2), msg.getInt(1), msg.getInt(3), msg.getInt(4));

void loop() {
  OSCMessage oscMsg;
  int packetSize = Udp.parsePacket();
  if (packetSize) {
    while (packetSize--) {
    if (!oscMsg.hasError()) {
      oscMsg.dispatch("/rgbw", rgbw);

attached (zip file) are more elaborate versions of this code - also including maxmsp and supercollider examples and kicad schematics.

Package icon f0neo.zip26.95 KB


here is how i built a wireless isolated dmx controller that takes osc input. the box uses an esp8266 to create a wifi access point that one can connect to with a laptop (or phone or whatever). opensound control messages sent to the box are converted into standard dmx commands. multiple clients can be connected and send dmx commands at the same time.

f0dmx 1

f0dmx 2

below is arduino code for the esp8266, the kicad schematics and some supercollider test code.

//Generic ESP8266 Module, 80 MHz

#include <ESP8266WiFi.h>
#include <WiFiUdp.h>
#include <OSCMessage.h>
#include <OSCData.h>
#include <LXESP8266UARTDMX.h>

#define PORT 19999  //EDIT osc port
const char *ssid = "f0dmx"; //EDIT softAccessPoint network name
const char *password = "mypass";  //EDIT password
#define CHANNEL 3 //EDIT wifi channel

WiFiUDP Udp;

void setup() {
  WiFi.softAP(ssid, password, CHANNEL);

void dmx(OSCMessage &msg) {
  int channel = msg.getInt(0);
  int value = msg.getInt(1);
  ESP8266DMX.setSlot(channel, value);

void start(OSCMessage &msg) {

void stop(OSCMessage &msg) {

void loop() {
  OSCMessage oscMsg;
  int packetSize = Udp.parsePacket();
  if (packetSize) {
    while (packetSize--) {
    if (!oscMsg.hasError()) {
      oscMsg.dispatch("/dmx", dmx);
      oscMsg.dispatch("/start", start);
      oscMsg.dispatch("/stop", stop);

bill of material...

1       dcdc            ROE-0505S       reichelt
1       xlr female      XLR 3KU         reichelt
1       optocoupler     6N 137          reichelt
1       ic              SN 75176BP      reichelt
1       box             BOPLA KS 420    reichelt
1       resistor        10K
1       resistor        470
3       resistor        10
1       resistor        120
2       cap             10uF
1       cap             100uF
1       regulator       LF 33 CV
1       micro           ESP8266-01
1       socket          4x2
1       usb cable

f0dmx kicad schematics

example of how to send osc from supercollider to the f0dmx box. make sure you send integers and not floats.

//make sure you are connected to the f0dmx wifi network
n= NetAddr("", 19999);  //the ip and port of the f0dmx box
n.sendMsg(\dmx, 9, 255)  //dmx channel 9, value 255
n.sendMsg(\dmx, 9, 0)
n.sendMsg(\dmx, 7, 100)  //dmx channel 7, value 100
n.sendMsg(\dmx, 7, 0)

n.sendMsg(\stop)  //usually not needed

Package icon kicad schematics27.48 KB


here's some python code for reading serial input from optoforce's 3d sensor and sending it over osc to maxmsp or supercollider.

the slightly odd baudrate of 1000000 isn't supported in sc nor max under osx, so i had to use python for this.

#for the 3d sensor OMD-30-SE-100N
#f.olofsson 2017

#first argument is serial port, second ip and third port.  e.g.
#python optoforceOsc.py '/dev/tty.usbmodem1451' '' 9999

import sys
from struct import *
from threading import Thread
import serial
from OSC import OSCServer, OSCClient, OSCMessage, OSCClientError

osc= OSCClient()
if len(sys.argv)>3:
  osc.connect((sys.argv[2], int(sys.argv[3])))  #send to address and port
        osc.connect(('', 57120))  #default send to sc on same computer

serport= '/dev/cu.usbmodem1411'
if len(sys.argv)>1:
  serport= sys.argv[1]

ser= serial.Serial(
  port= serport,
  baudrate= 1000000,
  parity= serial.PARITY_NONE,
  stopbits= serial.STOPBITS_ONE,
  bytesize= serial.EIGHTBITS,
  timeout= 1
print('connected to serial port: '+ser.portstr)

def oscInput(addr, tags, stuff, source):
  print stuff  #for now do nothing

server= OSCServer(('', 9998))  #receive from everywhere
server.addMsgHandler('/optoforceConfig', oscInput)
server_thread= Thread(target= server.serve_forever)

print('sending osc to: '+str(osc.address()))
print('listening for osc on port: '+str(server.address()[1]))

###configure sensor (optional)
conf= bytearray(9)
speed= 10  #0, 1, 3, 10, 33, 100 (default 10)
filter= 3   #0 - 6 (default 4)
zero= 255   #0, 255
checksum= 170+0+50+3+speed+filter+zero
conf[0]= 170
conf[1]= 0
conf[2]= 50
conf[3]= 3
conf[4]= speed
conf[5]= filter
conf[6]= zero
conf[7]= checksum>>8
conf[8]= checksum&255

def main():
  while True:
    b= ser.read(4)
    header= unpack('BBBB', b)
    if header==(170, 7, 8, 10): #data
      b= ser.read(12)
      counter= unpack('>H', b[0:2])[0]
      status= unpack('>H', b[2:4])[0]
      xyz= unpack('>hhh', b[4:10])
      checksum= unpack('>H', b[10:12])[0]
      sum= (170+7+8+10)
      for i in range(10):
        sum= sum+ord(b[i])
      if checksum==sum:
        #print(counter, status, xyz)
        msg= OSCMessage()
        except OSCClientError:
          print 'osc: could not send to address'
        print 'data: checksum error'
        print checksum
      if header==(170, 0, 80, 1): #status
        b= ser.read(3)
        status= unpack('B', b[0])[0]
        checksum= unpack('>H', b[1:3])[0]
        if checksum!=(170+0+80+1+status):
          print 'status: checksum error'
          print checksum
        print 'header: serial read error'
        print header

if __name__ == '__main__':
  except KeyboardInterrupt:

optoforce 3d sensor with maxmsp from redFrik on Vimeo.

optoforce 3d sensor with supercollider from redFrik on Vimeo.


Subscribe to f0blog RSS