electronics

syntjuntan

i got to design and build version 2 of syntjuntan's sewable synthesizer circuit. for this version they wanted to add an on-board amplifier that could drive a passive speaker element.

the circuit now has three schmitt triggers and can run on 3-12V. the amplifier is the classic lm386 and the connector pads around the board are made to fit needle and conductive thread as well as being crocodile friendly.

there are some options as standard through-hole soldering pads (a fourth schmitt trigger and x10 extra gain). the circuit can also be used as a standalone audio amplifier - just ignore the schmitt triggers and connect your own signal to the in pad.

anyway, lots of fun mass producing this and in the process i learned how to do hot-air smd soldering with stencil and solder paste plus got to know kicad a bit better.

i also built a test rig with an arduino and some pogo pins. it both scans for short-cuts and tests the sound.

syntjuntakrets 2 2

syntjuntakrets 2 4

syntjuntakrets 2 5

dragspel

this board is using an old raspberry pi 1 to control the speed of computer fans. the electronics are pretty simple (see attached schematics below): it takes 7-36V input power, has twelve mosfets for pwm control and finally a dc/dc converter to power the rpi.
it was built for controlling pc cooling fans but can also drive other types of dc motors, lightbulbs or solenoids.
the off button is there to safely power down the raspberry pi.

the trick with this though is that the system can be livecoded over wifi using supercollider, maxmsp or any other osc capable program. so when you start the board the rpi sets up a wireless access point and starts a python script that accepts incoming opensoundcontrol messages. at startup the rpi1 will also start supercollider and load a file (dragspelFans.scd) that is meant to contain whatever code you'd like to run as default. this file you later overwrite with your own sc code that you've developed/livecoded using your laptop.

dragspel

below are step-by-step instructions on how i set this up plus the relevant python and supercollider code. it should work on all rpi models but here the rpi1 or rpi0 is assumed.

//--preparation
* download and install raspbian-stretch-lite onto a 2gb sd card
* to enable ssh create an empty file on the sd card. call it ssh. (this terminal command touch /Volumes/boot/ssh will do it on osx or just create an empty textfile and save it without any file extension)
* connect your rpi to your home router via ethernet and type the following in terminal on your laptop:
* ssh-keygen -R raspberrypi.local
* ssh pi@raspberrypi.local #default password is raspberry
* sudo raspi-config #change password to _____, set memory split to 16 under advanced, change hostname to fans under network, update, finish and reboot (sudo reboot)
* ssh pi@fans.local #log in again from your laptop
* sudo apt-get update
* sudo apt-get upgrade
* sudo apt-get dist-upgrade

//--python
this section will install osc and gpio libraries for python and also set up the python script to automatically start at system boot.
* sudo apt-get install python-liblo pigpio python-pigpio
* sudo crontab -e #and add the following line at the end (use ctrl+o and ctrl+x to save and exit):

@reboot /usr/bin/pigpiod -s 5 && /usr/bin/python /home/pi/dragspelFans.py

* nano ~/dragspelFans.py #and copy&paste in the following:

#f.olofsson2016-2018
#pwm control for 12 fans/motors/leds

#NOTE: make sure to run this in terminal first...
# sudo pigpiod -s 5

import sys
from os import system
from time import sleep
import pigpio
from liblo import *

inport= 9999  #for osc commands to this python script
pinoff= 2  #bcm numbering
pins= [3, 4, 14, 15, 17, 18, 27, 22, 23, 24, 10, 9]  #bcm numbering - more can be added here
target= ('127.0.0.1', 57120)  #for osc to sclang
hz= 800  #pwm frequency in hz - note may need to adapt -s option in sudo pigpio -s 5 above
range= 100  #duty cycle range 0 to 100

pi= pigpio.pi()
pi.set_mode(pinoff, pigpio.INPUT)  #no internal pullup needed
for pin in pins:
  pi.set_mode(pin, pigpio.OUTPUT)
  pi.set_PWM_frequency(pin, hz)
  pi.set_PWM_range(pin, range)
  pi.set_PWM_dutycycle(pin, 0)

class MyServer(ServerThread):
        def __init__(self):
                ServerThread.__init__(self, inport)
        @make_method('/pwms', 'i'*len(pins))
        def pwms_callback(self, path, args):
                #print args  #debug
                i= 0
                for pin in pins:
                        pi.set_PWM_dutycycle(pin, min(max(0, args[i]), range))
                        i= i+1
        @make_method('/shutdown', '')
        def shutdown_callback(self, path, args):
                stop('sudo halt -p')  #turn off rpi
        @make_method('/reboot', '')
        def reboot_callback(self, path, args):
                stop('sudo reboot')  #reboot rpi
        @make_method('/start', '')
        def start_callback(self, path, args):
                send(target, '/start', 1)  #start default program in supercollider
        @make_method('/stop', '')
        def stop_callback(self, path, args):
                send(target, '/stop', 0)  #stop default program in supercollider
                for pin in pins:  #and also set all pwm to 0
                        pi.set_PWM_dutycycle(pin, 0)
        @make_method(None, None)
        def fallback(self, path, args):
                print 'received unknown message "%s"' % path

def stop(cmd):
        pi.stop()
        server.stop()
        system('killall pigpiod sclang')
        system(cmd)
        sleep(1)
        sys.exit()

try:
        server= MyServer()
except ServerError, err:
        print str(err)
        sys.exit()
server.start()

def main():
        while True:
                if pi.read(pinoff)==0:
                        print 'shutting down...'
                        stop('sudo halt -p')
                sleep(0.5)

if __name__ == '__main__':
        try:
                main()
        except KeyboardInterrupt:
                pi.stop()

again use ctrl+o and ctrl+x to save and exit. now sudo reboot and then try to send osc commands to the rpi. here's how to send some test osc messages from your laptop to the rpi using supercollider...

n= NetAddr("fans.local", 9999);
n.sendMsg(\pwms, *[50, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0])  //the number of integers should match the number of pins and range in your python code (here 12 pins, 0-100)
n.sendMsg(\pwms, *[25, 50, 75, 0, 0, 0, 0, 0, 0, 0, 0, 0])  //first pin 25%, second %50 third 75%, rest 0
n.sendMsg(\pwms, *[0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0])  //all off

you can also try to connect pin bcm2 to ground. that should now act like an off button and turn off the rpi in a safe way.

//--supercollider
this section is optional. only install supercollider if you want to run your rpi as a standalone installation or something similar. so if you plan to always remote control the system you can skip over this step.
note: this is for rpi0&rpi1, for rpi2&rpi3 change all references to supercolliderStandaloneRPI1 below to supercolliderStandaloneRPI2
see https://github.com/redFrik/supercolliderStandaloneRPI1#stretch-lite for more details (this page also show how to install jackd if you need audio from your rpi).
* sudo apt-get install libqt5webkit5 libqt5sensors5 libqt5positioning5 libfftw3-bin libcwiid1 git libasound2-dev libsamplerate0-dev libsndfile1-dev libreadline-dev xvfb libjack-jackd2-0
* cd ~
* git clone https://github.com/redFrik/supercolliderStandaloneRPI1 --depth 1
* mkdir -p ~/.config/SuperCollider
* cp supercolliderStandaloneRPI1/sc_ide_conf_temp.yaml ~/.config/SuperCollider/sc_ide_conf.yaml
* cd supercolliderStandaloneRPI1
* nano autostart.sh #and change the script to look like this:

#!/bin/bash
./sclang -a -l sclang.yaml ../dragspelFans.scd

* nano share/user/startup.scd #and add the following two lines:

OSCFunc({"/home/pi/dragspelFans.scd".load}, \start).permanent= true;
OSCFunc({CmdPeriod.run}, \stop).permanent= true;

* mkdir share/user/Extensions
* nano share/user/Extensions/DragspelFans.sc #and copy&paste in the following:

//f.olofsson2016-2018 - for controlling 12ch computer fan switch board
DragspelFans {
        var <rpi, num, vals, lastv, <>debug;
        *new {|debug= false, rpi, num= 12|
                ^super.new.initDragspelFans(debug, rpi, num);
        }
        initDragspelFans {|d, r, n|
                num= n;
                if(r.notNil, {
                        rpi= r;
                }, {
                        try{
                                rpi= NetAddr("fans.local", 9999);
                        } {|err|
                                "could not connect to rpi.\n make sure you are connected to the wifi network 'dragspel'.".warn;
                                rpi= NetAddr("127.0.0.1", 9999);  //temp just for testing
                        };
                });
                debug= d;
                vals= 0!num;
        }

        setAll {|val= 100|  //val should be 0 to 100
                vals= val!num;
                this.prSend;
        }
        clearAll {
                vals= 0!num;
                this.prSend;
        }
        val {|index, val|  //index should be 0-11, val 0-100
                vals= vals.put(index, val);
                this.prSend;
        }
        arr {|arr|  //arr should be 12 numbers in an array
                vals= arr;
                this.prSend;
        }

        shutdown {
                rpi.sendMsg(\shutdown);
        }
        reboot {
                rpi.sendMsg(\reboot);
        }
        start {
                rpi.sendMsg(\start);
        }
        stop {
                rpi.sendMsg(\stop);
        }

        //--private
        prSend {|v|
                if(debug, {
                        vals.postln;
                });
                v= vals.clip(0, 100).round.asInteger;
                if(v!=lastv, {  //filter out repeats
                        lastv= v;
                        rpi.sendMsg(\pwms, *v);  //send to dragspelFans.py
                });
        }
}
*/

* nano ~/dragspelFans.scd #and copy&paste in the following:

//demo autostart script - put your own standalone code in here
d= DragspelFans.new;
Event.addEventType(\fans, {d.val(~index, ~val)});
Pbind(\type, \fans, \dur, 0.5, \index, Pseq([0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11], inf), \val, Pwhite(0, 100, inf)).play;

* crontab -e #and add the following to the end (note no sudo here this time)

@reboot cd /home/pi/supercolliderStandaloneRPI1 && xvfb-run ./autostart.sh

now sudo reboot and supercollider should automatically start the code in dragspelFans.scd. it'll take a while so give it a minute or two.

to test it more run the following supercollider code on your laptop...

n= NetAddr("fans.local", 9999);
n.sendMsg(\stop);  //first stop the dragspelFans.scd script
n.sendMsg(\pwms, *[25, 50, 75, 0, 0, 0, 0, 0, 0, 0, 0, 0]);  //set pwm manually

//install the DragspelFans.sc class on your laptop sc and also try the following example code

a= DragspelFans(true);  //might take a moment or two
CmdPeriod.doOnce({a.clearAll});  //optional

//version0 - all on or off
a.setAll
a.clearAll
a.setAll(50)  //set all to some value 0-100
a.clearAll

//version1 - using an array
a.arr([0, 0, 100, 0, 0, 100, 0, 0, 100, 0, 0, 100])  //turn on some
a.arr([0, 100, 0, 0, 100, 0, 0, 100, 0, 0, 100, 0])  //turn some other fans
a.arr([30, 0, 0, 40, 100, 0, 40, 0, 0, 80, 0, 0])  //a few slower
a.clearAll

//version2 - set index to value
a.val(9, 100);
a.val(9, 0);
a.val(11, 100);
a.val(11, 0);
a.val(11, 60);
a.val(11, 0);

//fade in each fan in order
(
r= Routine.run({
        12.do{|j|
                100.do{|i|
                        a.val(j, i);
                        0.05.wait;
                };
                100.do{|i|
                        a.val(j, 99-i);
                        0.05.wait;
                };
        };
});
)
r.stop;

//using patterns
a= DragspelFans.new;
Event.addEventType(\fans, {a.val(~index, ~val)});
Pdef(\test, Pbind(\type, \fans, \dur, 0.125, \index, Pseq([0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11].scramble, inf), \val, Pwhite(0, 100, inf))).play;
Pdef(\test).stop;

a.start;  //start the dragspelFans.scd script on the rpi again
a.stop;
a.reboot;
a.shutdown;

or test it using the attached maxmsp patch.

fansStandaloneController

//--wifi softap
this section is optional. it will set up a wifi access point served from the rpi. basically taken from https://www.raspberrypi.org/documentation/configuration/wireless/access-point.md
* sudo apt-get install dnsmasq hostapd
* sudo systemctl stop dnsmasq
* sudo systemctl stop hostapd
* sudo nano /etc/dhcpcd.conf #and add the following to the end:

interface wlan0
    static ip_address=192.168.4.1/24

* sudo service dhcpcd restart
* sudo nano /etc/dnsmasq.conf #and add the following two lines to the bottom:

interface=wlan0
dhcp-range=192.168.4.2,192.168.4.50,255.255.255.0,4h

* sudo nano /etc/hostapd/hostapd.conf #and add the following (remember to set passphrase 8-64 characters):

interface=wlan0
driver=nl80211
ssid=dragspel
hw_mode=g
channel=6
wmm_enabled=0
macaddr_acl=0
auth_algs=1
ignore_broadcast_ssid=0
wpa=2
wpa_passphrase=________
wpa_key_mgmt=WPA-PSK
wpa_pairwise=TKIP
rsn_pairwise=CCMP

* sudo nano /etc/default/hostapd #and change one line to the following:

DAEMON_CONF="/etc/hostapd/hostapd.conf"

* sudo systemctl start hostapd
* sudo systemctl start dnsmasq

now sudo reboot on the rpi, log on to dragspel wifi network from your laptop and try to send some osc commands.

update 180225: major rewrite to use pigpio instead of RPi.GPIO and also raspbian stretch instead of jessie. pwm works much better.

paper speakers

here's some technical information on a collaboration with visual artist Jenny Michel. it's an sounding art installation that has previously been shown at galerie feldbuschwiesner and städtische galerie wolfsburg, and is now (sept2016) up and running at smac project space in berlin. also exhibited in wiesbaden and at kunstverein-tiergarten in berlin.

'traps', as the piece is called, consists of speakers made out of paper and enamelled copper wire. the wire is embedded into the paper in the shape of a coil and two strong magnets are situated on the back. the paper is manually layered and filled with prints and later perforated with cutouts. behind the paper is also a small circuit with a microcontroller, an amplifier and an antenna - all hand soldered dead-bug style. power comes from a shared 5v wall adapter.

traps consists of around 30 individual speakers and they all react on each other via their antennas. they also pick up different electromagnetic fields - but we can't say in exactly which frequency range they are sensitive as the antennas are made with arbitrary lengths and shapes (they're also copper wire).

the sound is synthesised with the microcontroller (attiny45). loudness and quality varies depending on the shape of the speakers - they're all individual - but in general the resulting sounds are quite noisy and piercing. the code was written to create a lot of variation and not just sonify the raw antenna input. so it's more of an interpretation than a direct translation of trapped radio frequency signals to sound as we first had planned. we also wanted harsher electronic sounds as it both fits better with the visual impression and that that type of square wave audio work very well in these non-linear lo-fi speakers.

there are also two modes: if one quickly turn the power on-off-on, the installation will start in 'vernissage mode' and play more sound than if one just turn the power on as normal (look for the eeprom part in the code below to see how it works more in detail).

in total we built 50 circuits and many more paper speakers. though ~30 are enough to fill medium sized gallery.





here's the code...

//f.olofsson 2015-2016
//select ATtiny, 1MHz (internal)
//decreased durMax in two places from 80000 to 8000

#include <EEPROM.h>

int durPause;
unsigned long durMax;
byte pausePer;
void setup() {
  randomSeed(analogRead(3));
  pinMode(4, OUTPUT);
  byte magic = EEPROM.read(0);
  if (magic == 123) { //lots of sound - chaotic opening mode
    durPause = 15000;
    durMax = 8000;
    pausePer = 67;  //percentage
    for (byte i = 0; i < 3; i++) {  //beep three times at startup
      prgStatic(100);
      prgPause(100);
    }
  } else {  //default - soft gallery mode
    durPause = 30000;
    durMax = 8000;
    pausePer = 75;  //percentage
    EEPROM.write(0, 123);
    delay(3000);  //power on for <3sec & then next time mode 1
    prgStatic(1500);  //make a tone at startup to know all working
  }
  EEPROM.write(0, 255);
}
void loop() {
  prgNoise(analogRead(3));
  if (random(100) < pausePer) {
    prgPause(durPause);
  } else {
    unsigned long dur = random(durMax);
    switch (analogRead(3) % 7) {
      case 0:
        prgPause(dur);
        break;
      case 1:
        prgNoise(dur);
        break;
      case 2:
        prgNoise(dur);
        break;
      case 3:
        prgChunks(dur);
        break;
      case 4:
        prgChunks(dur);
        break;
      case 5:
        prgBitbang(dur);
        break;
      case 6:
        prgImpulses(dur);
        break;
    }
  }
}
void prgPause(unsigned long dur) {
  analogWrite(4, 0);
  pinMode(0, OUTPUT);
  digitalWrite(0, 0);
  delay(dur);
  pinMode(0, INPUT);
}
void prgStatic(int dur) {
  analogWrite(4, 127);
  delay(dur);
}
void prgNoise(unsigned long dur) {
  unsigned long stamp = millis();
  while (millis() - stamp < dur) {
    analogWrite(4, analogRead(3) >> 2);
  }
}
void prgNoise2(unsigned long dur) {
  unsigned long stamp = millis();
  while (millis() - stamp < dur) {
    analogWrite(4, analogRead(3) >> 2);
    delay(1);
  }
}
void prgChunks(unsigned long dur) {
  unsigned long stamp = millis();
  byte base = (analogRead(3) >> 10) * 255; //either 0 or 255
  while (millis() - stamp < dur) {
    int val = analogRead(3);
    analogWrite(4, val >> 2);
    delay(val);
  }
}
void prgChunks2(unsigned long dur) {
  unsigned long stamp = millis();
  byte base = (analogRead(3) >> 10) * 255; //either 0 or 255
  while (millis() - stamp < dur) {
    int val = analogRead(3);
    analogWrite(4, val >> 2);
    delay(val / 2);
    analogWrite(4, base);
    delay(val / 2);
  }
}
void prgBitbang(unsigned long dur) {
  unsigned long stamp = millis();
  while (millis() - stamp < dur) {
    int val = analogRead(3 >> 2);
    for (byte i = 0; i < 8; i++) {
      digitalWrite(4, val >> i & 1);
    }
  }
}
void prgImpulses(unsigned long dur) {
  unsigned long stamp = millis();
  while (millis() - stamp < dur) {
    int val = analogRead(3);
    digitalWrite(4, 1);
    digitalWrite(4, 0);
    delay(val);
  }
}

note the use of the lm386 n-4. it is more powerful than the n1, n3 variants.

stine

next week in Bucharest we'll be setting up the subjective frequency transducer for the third time. i described the sound/vibration generating part of this system before but didn't write much about how the controllers work.

so for each sound channel (i.e. each bass transducer) there's a wireless controller that enables the audience to set their preferred frequency. technically it's done with a rotary encoder, a esp8266 wifi module, a mega168 and a big 7-segment lcd. the circuit runs off two AAA batteries.

when someone touches the rotary encoder, the circuit wakes up and starts sending osc messages to a laptop running supercollider. supercollider receives the values, starts playing an oscillator and sends the sound to the corresponding audio channel. when done, sc fades out the oscillator and sends an off message to the circuit and the controller goes back to sleep mode.

i spent quite some time optimising the microcontroller (atmega168) code. it was hard to both reduce power consumption and still being able to quickly wake up and react on user input as well as on incoming osc messages. it's a common problem with battery powered radio devices.

also getting the esp8266 to handle osc messages was a pain. here and here are some more info and simplified versions of that.

in the end, the code for talking to these circuits in supercollider looked like this:

//sc example: sending. turn off circuit 3 and set it back to initial frequency
~encode= {|id, on, hi, lo| (id&255<<24)|(on&255<<16)|(hi&255<<8)|(lo&255)};
~encode.value(3, 0, 0, ~initFreq);
//sc example: receiving. decoding data from the four esp8266
OSCdef(\sti, {|msg, time, addr|
        var id= msg[1]>>24;
        var onoff= (msg[1]>>16)&255;
        var freq= (msg[1]&65280)+(msg[1]&255);
        [\id, id, \onoff, onoff, \freq, freq].post;
}, \sti);

the microcontroller code could still be improved. i'd like it to wake up on both wdt and uart. at the moment the circuit is drawing 22mA average in off+idle state, and 33mA average with display set to '20' which is okey but not optimal. and when sending osc you get current spikes of a few hundred milliamps but there's no way around that.

//f.olofsson 2015-2016

#define ID 3
#define FREQ 0 //start frequency
#define FREQ_MIN 0
#define FREQ_MAX 9999
#define WLAN_SSID "MYNETWORK"
#define WLAN_PASS "MYPASSWORD"
#define WLAN_ADDR "192.168.43.99" //laptop static ip
#define WLAN_PORT 1112
String tag = "/tap"; //incomming osc addy

#include <avr/sleep.h>
#include <avr/power.h>
#include <avr/wdt.h>

#include <Encoder.h>

Encoder myEnc(3, 2);
float freq = FREQ;  //starting frequency
int freqLast = -999;

byte state = 0;
int enc = 0;
byte dig = 0;
byte cnt = 0;
boolean resp;

uint8_t buf[16];  //osc message

void setup() {
  pinMode(2, INPUT_PULLUP);  //encoder a
  pinMode(3, INPUT_PULLUP);  //encoder b
  pinMode(4, INPUT_PULLUP);  //encoder button
  DDRB = B11111111;  //segments
  DDRC = B00001111;  //digits selector

  //--set up wifi
  Serial.begin(115200);
  Serial.setTimeout(10000);
  resp = Serial.find("ready\r\n");
  progressDot(1);
  Serial.println("AT+CWMODE=1");
  resp = Serial.find("OK\r\n");
  progressDot(2);
  do {
    Serial.print("AT+CWJAP=\"");
    Serial.print(WLAN_SSID);
    Serial.print("\",\"");
    Serial.print(WLAN_PASS);
    Serial.println("\"");
    resp = Serial.find("OK\r\n");
  } while (!resp);
  progressDot(3);
  Serial.println("AT+CIPMUX=1");
  resp = Serial.find("OK\r\n");
  progressDot(4);
  Serial.print("AT+CIPSTART=4,\"UDP\",\"");
  Serial.print(WLAN_ADDR);
  Serial.print("\",57120,");  //supercollider default port
  Serial.print(WLAN_PORT);
  Serial.println(",0");
  resp = Serial.find("OK\r\n");
  Serial.setTimeout(1000);
  displayClear();

  //--osc message
  buf[0] = 47;   // /
  buf[1] = 115;  // s
  buf[2] = 116;  // t
  buf[3] = 105;  // i
  buf[4] = 0;
  buf[5] = 0;
  buf[6] = 0;
  buf[7] = 0;
  buf[8] = 44;   // ,
  buf[9] = 105;  // i
  buf[10] = 0;
  buf[11] = 0;
  buf[12] = ID;  // a high   (id)
  buf[13] = state; // a low  (onoff)
  buf[14] = 0;   // b high   (freq hi)
  buf[15] = 0;   // b low    (freq lo)

  //--timer
  noInterrupts();
  TCCR1A = 0;
  TCCR1B = 0;
  TCNT1 = 0;
  OCR1A = 32768;  //62.5Hz display updaterate
  TCCR1B |= (1 << WGM12);
  TCCR1B |= (1 << CS10);  //prescaler divide by 1
  TIMSK1 |= (1 << OCIE1A);
  interrupts();

  //--sleep
  MCUSR &= ~(1 << WDRF);
  WDTCSR |= (1 << WDCE) | (1 << WDE);
  WDTCSR = 1 << WDP0 | 1 << WDP1;
  WDTCSR |= _BV(WDIE);
}

volatile int f_wdt = 1; //watchdog wakeup
ISR(WDT_vect) {
  if (f_wdt == 0) {
    f_wdt = 1;
  }
}
void enterSleep(void) {
  set_sleep_mode(SLEEP_MODE_IDLE);
  sleep_enable();
  sleep_mode();
  sleep_disable();
  power_all_enable();
}

ISR(TIMER1_COMPA_vect) {  //update display periodically
  if (state == 2) {
    displayFreq();
  }
}

void sendOsc() {
  buf[13] = state;
  buf[14] = int(freq) >> 8;
  buf[15] = int(freq) & 255;
  Serial.println("AT+CIPSEND=4,16");
  Serial.find(">");
  Serial.write(buf, sizeof(buf));
  resp = Serial.find("OK\r\n");
}

void loop() {
  dig = 1 - ((PIND >> 4) & 1);  //encoder momentary button
  switch (state) {
    case 2:  //running (display on)
      enc = myEnc.read();
      if (enc != 0) {
        float incStep = enc / 2.0;
        myEnc.write(0);
        freq = max(FREQ_MIN, min(FREQ_MAX, freq + incStep));
        if (int(freq) != freqLast) {
          sendOsc();
          freqLast = int(freq);
        }
      }
      if (dig == 1) {  //TODO: or timeout here?
        state = 3;
      }
      break;
    case 0:  //sleeping (display off)
      f_wdt = 0;
      enterSleep();
      enc = myEnc.read();
      if ((dig == 1) || (enc != 0)) {
        state = 1;
        freq = FREQ; //reset
        sendOsc();
      }
      break;
    case 3:  //turning off when button released
      displayClear();
      if (dig == 0) {
        state = 0;
        sendOsc();
      }
      break;
    case 1:  //turning on when button released
      if ((dig == 0) || (enc != 0)) {
        state = 2;
        myEnc.write(0);
      }
  }

  //--receive osc
  while (Serial.available()) {
    String abc = Serial.readStringUntil('\n');
    if (abc.startsWith("+IPD,4,16:" + tag)) {
      //if(abc[22]==ID) { //optional filter by device ID
      if (abc[23] == 0) {
        displayClear();
        state = 0;
      } else {
        state = 2;
        myEnc.write(0);
      }
      freq = (abc[24] << 8) + abc[25];
    }
  }
}
void displayClear() {
  PORTC = B00001111;
  PORTB = B00000000;
}
void progressDot(byte index) {
  setChr(255, true);
  selDig(index);
}
void displayFreq() {
  int val = freq; //cuts off fraction
  switch (cnt) {
    case 0:
      if (val > 999) {
        setChr((val % 10000) / 1000, false);
      } else {
        setChr(255, false);
      }
      selDig(1);
      cnt = 1;
      break;
    case 1:
      if (val > 99) {
        setChr((val % 1000) / 100, false);
      } else {
        setChr(255, false);
      }
      selDig(2);
      cnt = 2;
      break;
    case 2:
      if (val > 9) {
        setChr((val % 100) / 10, false);
      } else {
        setChr(255, false);
      }
      selDig(3);
      cnt = 3;
      break;
    case 3:
      setChr(val % 10, false);
      selDig(4);
      cnt = 0;
  }
}

void selDig(byte index) {
  switch (index) {
    case 1:
      PORTC = B00001110;
      break;
    case 2:
      PORTC = B00001101;
      break;
    case 3:
      PORTC = B00001011;
      break;
    case 4:
      PORTC = B00000111;
  }
}

void setChr(byte chr, bool dot) {
  switch (chr) {
    case 255:  //clear
      PORTB = B00000000;
      break;
    case 0:
      PORTB = B11111100;
      break;
    case 1:
      PORTB = B01100000;
      break;
    case 2:
      PORTB = B11011010;
      break;
    case 3:
      PORTB = B11110010;
      break;
    case 4:
      PORTB = B01100110;
      break;
    case 5:
      PORTB = B10110110;
      break;
    case 6:
      PORTB = B10111110;
      break;
    case 7:
      PORTB = B11100000;
      break;
    case 8:
      PORTB = B11111110;
      break;
    case 9:
      PORTB = B11100110;
      break;
      /*
        case 10:  //A
        case 11:  //B
        case 12:  //C
        case 13:  //D
        case 14:  //E
        case 15:  //F
        case 16:  //G
        case 17:  //H
      */

  }
  if (dot) {
    PORTB |= B00000001;
  }
}

tamas

here another project. it's a box for replacing some old midi hardware. it can read 16 analog sensors, 16 digital sensors and control 16 leds via pwm. basically it is just a teensy plus a pwm breakout board from sparkfun. to easily access all the pins on the teensy, i also used the excellent Teensy 3.2 Breakout Board R3 by Daniel Gilbert.

attached are schematics, teensy code, and supercollider and maxmsp code for dealing with the serial communication.

tamas00

tamas01

update 161011: fixed a silly but severe error in the max patch

AttachmentSize
Binary Data TamasSerial.sc1.84 KB
Image icon tamas_teensy_schematics.png184.1 KB
Binary Data tamas_teensy.ino2.07 KB
Binary Data tamas_test.maxpat86.04 KB

mp3 speakers

for an upcoming installation we need a few speakers hanging on the walls playing back sound files in a loop. i found the dfplayer mini to work well. it's a small and cheap board that can play soundfiles from a sd-card and it has a built-in 3W amplifier. with a decent 5v batterybank (here 4400mAh) it can run for ~4 days continuously.

mp3speakers

esp8266 opensound control teensy

today i ported my opensound control esp8266 example for arduino to run on a teensy 3.

the version below is a bit simpler but still works the same. it is just to show how to send and receive osc messages directly in sc or max.

teensy code:

//f0 150705 - modified for teensy3 160430
//sending and receiving udp osc with an esp8266
//for teensy + esp8266 with firmare 0.9.5.2
#define WLAN_SSID  "ssid"
#define WLAN_PASS  "pass"
#define WLAN_ADDR  "192.168.1.3" //laptop running sc EDIT
#define ADDR "/tap" //incoming osc addy
#define PORT  1112  //incoming osc port
uint8_t buf[16];
char indata[12];
char inbuffer[256];
char OKrn[] = "OK\r\n";
byte wait_for_esp_response(int timeout, char* term = OKrn) {
  unsigned long t = millis();
  bool found = false;
  int i = 0;
  int len = strlen(term);
  while (millis() < (t + timeout)) {
    if (Serial1.available()) {
      inbuffer[i++] = Serial1.read();
      if (i >= len) {
        if (strncmp(inbuffer + i - len, term, len) == 0) {
          found = true;
          break;
        }
      }
    }
  }
  inbuffer[i] = 0;
  return found;
}
void setup() {
  //--osc message
  buf[0] = 47;   // /
  buf[1] = 115;  // s
  buf[2] = 116;  // t
  buf[3] = 105;  // i
  buf[4] = 0;
  buf[5] = 0;
  buf[6] = 0;
  buf[7] = 0;
  buf[8] = 44;   // ,
  buf[9] = 105;  // i
  buf[10] = 0;
  buf[11] = 0;
  buf[12] = 4;   // a
  buf[13] = 3;   // b
  buf[14] = 2;   // c
  buf[15] = 0;   // d
  pinMode(23, OUTPUT);
  Serial.begin(115200);   //usb serial for feedback
  delay(400);
  Serial1.begin(115200);  //teensy hardware pins 0 and 1
  Serial.println("starting");
  Serial.print("hard reset...");
  pinMode(4, OUTPUT);
  delay(10);
  pinMode(4, INPUT);
  Serial.print("ready...");
  boolean resp = wait_for_esp_response(1000, "ready\r\n");
  Serial.println(resp);
  Serial.print("mode1...");
  Serial1.println("AT+CWMODE=1");
  resp = wait_for_esp_response(1000);
  Serial.println(resp);
  Serial.print("connecting...");
  do {
    Serial1.print("AT+CWJAP=\"");
    Serial1.print(WLAN_SSID);
    Serial1.print("\",\"");
    Serial1.print(WLAN_PASS);
    Serial1.println("\"");
    resp = wait_for_esp_response(3000);
    Serial.print(resp);
  } while (!resp);
  Serial.print("\nmux1...");
  Serial1.println("AT+CIPMUX=1");
  resp = wait_for_esp_response(1000);
  Serial.println(resp);
  Serial.print("udp...");
  Serial1.print("AT+CIPSTART=4,\"UDP\",\"");
  Serial1.print(WLAN_ADDR);
  Serial1.print("\",57120,");
  Serial1.print(PORT);
  Serial1.println(",0");
  resp = wait_for_esp_response(1000);
  Serial.println(resp);
  Serial.println("setup done");
}
void loop() {
  if (wait_for_esp_response(1000, "\r\n+IPD,4,16:")) {
    if (wait_for_esp_response(1000, ADDR)) {
      Serial1.readBytes(indata, 12);
      buf[12] = indata[8] + 1; //add one to incomming values
      buf[13] = indata[9] + 1;
      buf[14] = indata[10] + 1;
      buf[15] = indata[11] + 1;
      Serial.println(int(indata[8]));
      Serial.println(int(indata[9]));
      Serial.println(int(indata[10]));
      Serial.println(int(indata[11]));
      Serial1.println("AT+CIPSEND=4,16");
      if (wait_for_esp_response(1000, "> ")) {
        Serial1.write(buf, sizeof(buf));
        if (wait_for_esp_response(1000)) {
          Serial.println("reply sent!");
        }
      }
    }
  }
}

supercollider code:

(
//--call&response
var send= 0, last= Main.elapsedTime;
OSCdef(\sti, {|msg, time, addr|
        //should receive the values you sent +1
        ([msg[1]>>24, (msg[1]>>16)&255, (msg[1]>>8)&255, msg[1]&255]).post;
        (" % sec since last: %, % sec since sent").format(addr, time-last, time-send).postln;
        last= time;
}, \sti);
n= NetAddr("192.168.1.4", 1112); //esp8266 ip address EDIT
f= {|id, on, hi, lo| (id&255<<24)|(on&255<<16)|(hi&255<<8)|(lo&255)};
r= Routine.run({
        inf.do{|i|
                n.sendMsg(\tap, f.value(4, 3, i.asInteger%256, 1));
                send= Main.elapsedTime;
                0.5.wait;
        };
});
)

note: my new and better way to do this is described here

update 180212: removed an unneeded wait for response. thanks Niklas!

AttachmentSize
Package icon maxmsp example patch1.56 KB

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