Low Frequency Publication

Materialising the Blackbox

Introduction

In this special issue we will explore the physicality behind slick black boxes as for example found in everyone's pockets today. Be it hardware or software. The goal is to make the interactions, interfaces and connections explicit through hands-on research and play. Informed by the fact all modern day electronics still adhere to the paradigm of modularity, like the earliest computer designs we will collaboratively build one or more devices that explore notions of modularity, complexity/simplicity, interfaces, darkpatterns, input/output while explicitly giving insight into the black box, but this time including a manual.

To encourage affection with the materiality of the blackbox we will create our own. Starting of by constructing the building blocks of a synthesizer, allowing the creation of complex outputs by interfacing/combining relatively simple operations. As a clear framework we will start off by working with sound, your fastest sensor. Compatible with the possibly familiar 'Eurorack' format (as developed by Doepfer) we will be constructing several electronic modules that allow the output of one module to be the input for the next. Expanding upon the original discrete, or analog approach, each of our modules offer a programmable interface, eventually allowing for interfacing beyond the blackbox.

As single modules perform one job and one job well, you will have to anticipate and even require the output of someone elses module in order for yours to work. Coinciding with your research we will create one or several 'outputs' consisting of an interface, electronics and a manual.

Guests

Dennis de Bel Dennis de Bel (1984, NL) is an applied artistic researcher, educator, radio amateur (call sign PD0WNED). In his practice he positions himself as producer, consumer, observer and distributor of critical knowledge focussed on technology. His work has been exhibited at Siggraph Los Angeles, Transmediale Berlin and hosted workshops in various collaborations at, for example, ISEA Hong Kong, Radical Networks New York. He participated in the Relearn summer schools and Libre Graphics Meetings besides being a guest tutor at the Design Academy Eindhoven and the Willem de Kooning Academy Rotterdam University of Applied Science. In 2017 he co-founded Varia, a Rotterdam based space for developing collective approaches towards everyday technology. De Bel holds a MA from the Piet Zwart Institute (NL) and most recently (Jul-Dec 2018) participated in the artist in residency program of the Institute for Provocation in Beijing.

http://dennisdebel.nl/

Olli Aarni

Olli Aarni (Oulu, Finland) makes experimental electronic music with vivid timbres and textures, static and slippery harmonies. He has released more than 20 records on four continents with labels like Aguirre, Flau and Lal Lal Lal. He has played in various European countries and Japan at events such as Flow Festival (Helsinki, Finland), Jauna Muzika (Vilnius, Lithuania) and The Gathering of Trans-Medial Publishers (Antwerpen, Belgium).

Aarni holds an MA in Finnish Language. Combining his passion for linguistics and music, he has created a sound poetry piece, consisting of the Finnish sound alphabet, and two sound poems created with this alphabet. He has created music with plants as part of the multimedia artist group Band of Weeds. Currently he is working on a site-specific music piece for electronic instruments and the Finnish traditional instrument kantele.

de Player Nor a white cube (read gallery) or black box (read: theater) but a 'grey dome' where production meets performance meets possibilities..and everything in between http://deplayer.nl

Martin Howse Not sure where to begin, techno-shaman would cut his practice short. Check his 'micro research' here: http://www.1010.co.uk/

Schedule

The program consists of three main sections, building, interfacing and coding and going public. Bring headphones to every class!

Building

Getting your hands dirty.

Week 1 - Sept 17

Today you will become modules of a modular synth! First we need to construct them though:

Construct: Meergranen (Optionally + LFO)

pad: https://pad.xpub.nl/p/lfp1 (Keep build notes, address points of improvements, happy accidents and tips)

git: https://git.xpub.nl/XPUB/special-issue-x

build manual: File:Manual-meergranen.pdf (20MB PDF)

 BEFORE YOU POWER YOUR MODULE, LET ME TAKE A LOOK

arduino firmware: Arduino Firmware (ZIP file)

software: Arduino IDE + Driver

PLEASE BRING A MINI USB CABLE (with power + data lines) and Headphones (3.5mm jack)

homework:
-Play with the various Arduino Firmware (ZIP file) found in that zip file. Note some codes might need an external trigger (control voltage, 0-5v) in order to produce sound. Other codes might only produce triggers (no sound), used to sequence/trigger other modules. Make notes on the pad above what you find interesting, what functionality you would like to have, what sounds?
-Record your own sample, using the 'Memphis' example firmware and script below: http://pzwiki.wdka.nl/mediadesign/Category:Lfp#Adding_custom_audio_samples

---

Week 2 - Sept 23,24,25,28

Workshop with Olli Aarni

Notepad: https://pad.xpub.nl/p/olliworkshop

During the first part of the workshop the participants will learn about different interfaces of making sounds and music. We will explore such questions as: How do restrictions lead to creative solutions? How does technology affect the outcome of the creative process? How does the interface itself relate to its output?

We will listen to different sounds and develop our own concepts and categories for understanding, grouping and creating sounds. The process will combine language and sound in order to create a unique categorisation system, which will be used later as a basis for building a modular sound producing system.

Furthermore there will be a small introduction into modular synthesis and practical logic concerning your modules and demo of various in's and out's

Demo setup

28th September Excursion to Dutch Modular Festival
Please add your name if you are attending:
Dennis de Bel
Mika Motskobili
Mark van den Heuvel
Ioana Tomici

---

Week 3 - 1 Oct

Morning (Individual)

• Get everyones Arduino IDE to work
• Upload custom firmware

Afternoon (in groups of two)

• Arduino coding primer
• Arduino input/output primer/interfacing with the real world
• Interfacing with your neighbour

Assignment (individual or groups of two)

• Interface with physical world; manipulate your module with an input from the physical world or/and manipulate the physical world with your module. Think lights, plants, wind, sun, rain (ollie's examples of site specific audio works). Document on wiki (as these could be part of the publication)!

Week 4 - 8 Oct

PSU building, scavenge for 'test' case

Interfacing

Basics of arduino, interfacing with others, desiging interfaces (frontpanels) SOX

Laser cutter instructions (PDF)
Frontpanel source files (vector)

Week 5 - 15 Oct

Workshop with Olli Aarni (14, 15, 16) Arduino Basics

Week 6 - 5 Nov

DIWO - Interfacing with your neighbours

Week 7 - 12 Nov

Develop interactions

• DE PLAYER workshop Thursday 28.11

Publishing

Going public, manual

Week 8 - 19 Nov

Week 9 - 26 Nov

Week 10 - 3 Dec

Presentation at de Player

Resources

Software

http://pzwiki.wdka.nl/mediadesign/Arduino101

Arduino Firmware (ZIP file)

Hardware

Modules - Mult

A simple module; just a front panel and jack sockets connected to each other (tip to tip (+), sleeve (gnd) to sleeve). Creating a passive (non-powered/buffered/unsafe) crude kind of mixer! Notice the two sections of five jacks, distinguishing audio from CV. This is for safety, since our 'Meergranen' output (audio) is not protected from potential control voltages of -12v to 12v. SO always try to mix audio with audio and CV with CV (if you have spare arduinos you can igonre this message, because modulating audio with CV can be interesting!).

---

Modules - Arduino Tool 'Meergranen'

Meergranen, front+back, no frontpanel

NOTE: there is a bug in the IDC connection, pin 7 and 8 need to be bridged if you want to power the module through usb (for testing)
NOTE: the optional button is wired incorrectly and is not usable. It needs a jumper from 5v (arduino) pin and a jumper to any of the free digital pins see.
WARNING: the output port is UNPROTECTED agains overcurrent/voltage/reversepolarity. Use it as OUPUT and dont connect it to another output for example.

What can the jack inputs do?

The output of Meergranen (audio or PWM) delivers about 5v. Enough to easily light a LED (or activate another Meergranen!)

Adding custom audio samples

Download Arduino firmware examples here: Arduino Firmware (ZIP file) Indie the zip file you will find grains-sounds-master.zip, unzip and flash one of the arduino sketches found in the 'patches' folder. Grains-sounds is a basic sample player that allows you to manipulate pitch, start and end of a sample (using the potentiometers or control voltage). To add your own samples, just replace the 'sample.h' file with one of your own. To prepare an audio sample for this firmware:

-install sox (and Audacity ) (mac: install homebrew and then install brew install sox)
-make 3 second (loop) of a sound in Audacity for example
-convert stereo sound to mono
-export as wav file (16bit)
-in Terminal, navigate yo your exported soundfile and convert it to 8bit, 8000hz: (alternatively use the script below to convert your 16bit wav file exported from Audacity directly to sample.h!)

 sox your_sound_file.wav -t u8 -c 1 -r 8000 output.wav 
 xxd -i output.wav > sample.h   

you end up with a hexadecimal encoded soundfile now in an array. C code needs to know the length of the array before hand: at the bottom of sample.h it says the length of the file, for example 27278.

in sample.h search and replace the first line:

 unsigned char out2_wav[] = {

with, note you have to change the sound_lenght into that of your sample:

 #define SAMPLE_RATE 8000
 const int sound_length=27278;
 const unsigned char sound_data[] PROGMEM= {

Script

You can use this bash script to automatize the creation of sample.h (instructions below):

#!/bin/sh
# Prepares a sample.h file
# sed not used, should just werk (TM) everywhere
# Usage: ./samplify.sh my_sample.wav
# Or you can install samplify.sh in your ~/bin and call it
# from anywhere you like

# Convert original soundfile and create sample.h
# A temp file is needed oftherwise xxd is unable to generate 
# sample length information?
sox "${1}" -t u8 -c 1 -r 8000 /tmp/sample.wav
xxd -i /tmp/sample.wav > sample.h
rm /tmp/sample.wav

# Extract sample length
SAMPLE_LEN=$(tail -1 sample.h | cut -d ' ' -f 5 | tr -d ';')

# Inject SAMPLE_LEN in new file header
NEW_HEADER="#define SAMPLE_RATE 8000
const int sound_length=${SAMPLE_LEN};
const unsigned char sound_data[] PROGMEM= {"

# Remove first line of sample.h
echo "$(tail -n +2 sample.h)" > sample.h

# Prepend new header to sample.h
echo "$(echo "${NEW_HEADER}"; cat sample.h)" > sample.h

The latest version will be updated on the trimester's git repos! https://git.xpub.nl/XPUB/special-issue-x/src/branch/master/utils/samplify.sh

How to use the script: Copy paste the text above in a texteditor (raw text, not Textedit) and save as 'samplify.sh'. Open a terminal and make the file executable:

 chmod +x samplify.sh

Put your wave file in the same directory as samplify.sh and in terminal run:

 ./samplify.sh yourfile.wav

This will generate the sample.h file needed for the sample player arduino firmware as in the 'memphis' example. Just replace the sample.h in that folder with your newly generated one. Flash the arduino with the memphis code again and it should now play our own custom sample!

Pro tip: 27278 bytes is about the maximum lenght of sample storage on arduino nano (+ the script that plays the sample). If sound sample is a bit too long/big you can simply speed it up in Audacity, the script allows for pitch bending, so you can make up for the increase in speed. Possiblt there is some head room in the sample rate (8000hz) in the above example. Reducing this will result in smaller file, but lower quality (resolution). Possibly the playback speed will increase as well (since the script anticipates the sample rate of 8000hz, ofcourse this is adjustable by yourself).

Bill of Materials

Label	Part Type	Properties
for arduino	Male Headers	1x16
for arduino	Female Headers	1x16
C1 104	Capacitor	104, 100nF package cap-pth-small2; variant pth2
J1 - A2	3.5mm Switch Jack	size 3.5mm; variant 1; part # PJ301M-12
J2 - A1	3.5mm Switch Jack	size 3.5mm; variant 1; part # PJ301M-12
J3TRIG - A3	3.5mm Switch Jack	size 3.5mm; variant 1; part # PJ301M-12
J4 - A0	3.5mm Switch Jack	size 3.5mm; variant 1; part # PJ301M-12
J4 OUT	3.5mm Switch Jack	size 3.5mm; variant 1; part # PJ301M-12
JP	Header 5x2	package 2x5-ra; variant ra
LDR1	Photocell (LDR)	resistance@ dark 300 kOhms@ 10 seconds; package THT; resistance@ luminance 16 kOhms@ 10 lux
LDR2	Photocell (LDR)	resistance@ dark 300 kOhms@ 10 seconds; package THT; resistance@ luminance 16 kOhms@ 10 lux
LDR3	Photocell (LDR)	resistance@ dark 300 kOhms@ 10 seconds; package THT; resistance@ luminance 16 kOhms@ 10 lux
LDR4	Photocell (LDR)	resistance@ dark 300 kOhms@ 10 seconds; package THT; resistance@ luminance 16 kOhms@ 10 lux
LED1	Red (633nm) LED	package 3 mm [THT]; color Red (633nm); leg yes
LED2	Red (633nm) LED	package 3 mm [THT]; color Red (633nm); leg yes
LED3	Red (633nm) LED	package 3 mm [THT]; color Red (633nm); leg yes
LED4	Red (633nm) LED	package 3 mm [THT]; color Red (633nm); leg yes
NANO	Arduino Nano (Rev3.0)	type Arduino Nano (3.0)
P1 = A2	Rotary Potentiometer (Small)	package THT; size Rotary - 9mm; track Linear; maximum resistance 10kΩ; type Rotary Shaft Potentiometer
P2 = A1	Rotary Potentiometer (Small)	package THT; size Rotary - 9mm; track Linear; maximum resistance 10kΩ; type Rotary Shaft Potentiometer
P3 = A0	Rotary Potentiometer (Small)	package THT; size Rotary - 9mm; track Linear; maximum resistance 10kΩ; type Rotary Shaft Potentiometer
R1	0Ω Resistor	bands 5; package THT; tolerance ±5%; pin spacing 400 mil; resistance 0Ω
R2	0Ω Resistor	bands 5; package THT; tolerance ±5%; pin spacing 400 mil; resistance 0Ω
R3	1kΩ Resistor	bands 5; package THT; tolerance ±5%; pin spacing 400 mil; resistance 1kΩ
R4	1kΩ Resistor	bands 5; package THT; tolerance ±5%; pin spacing 400 mil; resistance 1kΩ
R5	1kΩ Resistor	bands 5; package THT; tolerance ±5%; pin spacing 400 mil; resistance 1kΩ
R6	10kΩ Resistor	bands 5; package THT; tolerance ±5%; pin spacing 400 mil; resistance 10kΩ
R7	1kΩ Resistor	bands 5; package THT; tolerance ±5%; pin spacing 400 mil; resistance 1kΩ
R8	10kΩ Resistor	bands 5; package THT; tolerance ±5%; pin spacing 400 mil; resistance 10kΩ
R9	150Ω Resistor	bands 5; package THT; tolerance ±5%; pin spacing 400 mil; resistance 150Ω
S1	SWITCH-MOMENTARY-2	package tactile-pth; variant pth

Shopping List

Amount	Part Type	Properties
2	Male Headers	1x16
2	Female Headers	1x16
1	Capacitor	104, 100nF package cap-pth-small2; variant pth2
5	3.5mm Switch Jack	size 3.5mm; variant 1; part # PJ301M-12
1	Header 5x2	package 2x5-ra; variant ra
4	Photocell (LDR)	resistance@ dark 300 kOhms@ 10 seconds; package THT; resistance@ luminance 16 kOhms@ 10 lux
4	Red (633nm) LED	package 3 mm [THT]; color Red (633nm); leg yes
1	Arduino Nano (Rev3.0)	type Arduino Nano (3.0)
3	Rotary Potentiometer (Small)	package THT; size Rotary - 9mm; track Linear; maximum resistance 10kΩ; type Rotary Shaft Potentiometer
2	0Ω Resistor	bands 5; package THT; tolerance ±5%; pin spacing 400 mil; resistance 0Ω
4	1kΩ Resistor	bands 5; package THT; tolerance ±5%; pin spacing 400 mil; resistance 1kΩ
2	10kΩ Resistor	bands 5; package THT; tolerance ±5%; pin spacing 400 mil; resistance 10kΩ
1	150Ω Resistor	bands 5; package THT; tolerance ±5%; pin spacing 400 mil; resistance 150Ω
1	SWITCH-MOMENTARY-2	package tactile-pth; variant pth

---

Modules - Low frequency oscillator

Analog lfo frequency oscillator, delivers waves below the speed of sound. Usefull for triggering other things (beats, filters, etc). Based on quad-opamp, can deliver up to 2x square wave + 2x triangle wave. In this configuration/pcb only 1x square + 1x triangle. Speed of oscillation depening on potentiometer.

Build Instructions

Building this module is a soft introduction into the world of electronics where humans cannot handle, build, or see the components they are using. Introducing: Surface Mount Devices > SDM (or surface mount technology > SMT). In contrast to 'through hole type' components, these smd parts don't need drilling at all, efficient! Not designed to be handled by humans, but for space saving and efficiency, you can still try!

Use the BOM (Bill Of Materials) to see what components you need. This time we introduce IC's, Transistors and IDC connectors. They all have a specific orientation. The white silkscreen on the PCB hints at this, but sometimes its hard to see (LED +, long leg goes into square hole) or drawn incorrectly:

BUG: The white silkscreen of the IDC connector (marked 'JP2') is wrong, Refer to the example how it should be (hint, 180deg turn).

Soldering SMD -put a little bit of solder on 1 pad of the pcb
-check the orientation of the IC (Integrated Circuit, the SMD component)
-CHECK AGAIN WHERE PIN 1 SHOULD GO!
-place smd ic correctly on the pads, keep in place with finger
-touch the leg that corresponds with the pad containing some solder
-let the solder melt, and remove the soldering iron
-now the ic is fixed in place!
-check the orientation again, now is the time to make corrections (when all pins are soldered its very very hard to remove the IC withouth damaging the board and ic.) solder the rest of the pins:
-clean your soldering tip (do this for every pin)
-touch the pin+pad with soldering tip, add some solder, remove soldering tip
-repeat.
-the pin spacing is small, dont add too much solder, clean tip after soldering each pin (clean bridges with solder wick).

---

Modules - Power Supply

Use a usb wall wart adaptor or powerbank (laptop WILL die!)
Credits: https://github.com/TomWhitwell/StupidUSBPower

Meergranen powered by Power Supply hooked up to a powerbank.

Up to four Meergranen (or other Eurorack modules) can be powered through this device (max current is aroun 150mA though!).

---

Modules - ESP8266wifi

Coming soon...

---

Frontpanels

Temporary place for the front panel vector files: http://dennisdebel.nl/downloads/xpub/frontpanels/ (soon on GIT).

Cables

Flat cables with IDC connectors ('eurorack power cables') (Lint- or Bandkabel in Dutch)
Patch cable (mono TS (Tip-Sleeve)3.5mm Male Jacks) ,

Glossary

Patch Cables - mono 3.5 mm male jack-jack cables used to interconnect eurorack modules.

Control Voltage - or CV, a signal used to control synths. typically within the -15 to +15v range (DC or AC).

Breadboard - or solderless-breadboard is a plastic board with interconnected holes for prototyping electronic circuits using jumper cables instead of (semi) permanent solder.

Soldering tin - combination of low melting point metals and resin flux. Sticks to copper, various metals and itself (not to aluminium, stainless steel, plastic, wood etc.)

PCB - Printed Circuit Board - Fiberglass (FR4) coated with copper. Etching away the copper allows for creating traces for electrical circuits. Professionally made boards are silskreened with soldermask (only exposing the places where solder is allowed and protecting the fragile copper traces + lettering for component placement.

Resistor - Slows down electrons, reducing current and thus voltage (Ohms Law, U=IxR) by converting it to heat. Units in Ohms > 1k = 1 kilo Ohm = 1000 Ohm, 0r = 0 Ohm (can be used to bride traces on a PCB)

LED - Light emitting diode, Has polarity: a positive (anode) and negative (cathode) leg. The longest leg is the positive one, keep this in mind when placing the component!

LDR - Light Dependant Resistor, a variable resitor based on light. The more light the lower the resistance and vice versa. Also called light sensor. Units in Ohms

Potentiometer - Rotary or sliding (like on audio mixers) variable resistor. Resistance is changed by turning the knob. Units in Ohms

Ceramic Capacitor - No polarity. Stores enegry until full and then releases it (like a bucket). Can be used for filtering signals (high frequencies will chose to go over a capacitor, low frequencies rather choose to go through a resistor). Units in Farad (pico, nano)

Electrolytic Capacitor - Has polarity. Stores enegry until full and then releases it (like a bucket). (high frequencies will chose to go over a capacitor, low frequencies rather choose to go through a resistor)Units in Farad (mirco, milli)

IC - Integrated Circuit, a single component housing various circuits. Examples: 555 timer, CMOS logic, Opamps,

IDC Connector - Special 'solderless' connectors for ribbon cable, press fit. Use vice, not hammer, be gentle on the brittle material.

Heatshrink - Tube that shrinks when heat is applied (use: lighter, paintstripper, soldering iron), handy for isolating wires, contacts and blocking external light when using LDRS

SMD/SMT - Surface Mount Device/Surface Mount Technology; components that are not soldered through holes, but directly to the PCB

THT - Through Hole Type: components that have long legs that go ...through holes before soldering

Trigger - a control voltage that gives a quick peak, used to trigger drums for example. Typically a harsh square wave.

Gate - a control voltage that follows a (ADSR) slope over time, useful for filters, pitch, notes. Typically a complex wave.

Transistor - Using a plumbing analogy: this is a tap: turn it open with a little effort (current) , allows many electrons to flow. Usable as switch (on off) and thus also to create oscillations (rapid on-off switches).

Ribbon cable - Also called flat cable, multiple parallel conducting wires. (Dutch: lint- or bandkabel)

Vactrols - Vactrols turn voltage into resistance. The 'hotter' the signal, the lower the resistance. Consist of one LED and one LDR, applying voltage to the LED creates light, influencing the resistance of the LDR.

Wire Wrap - before through hole and smd, there was wire wrap, wrap the components legs around a header pin for a airtight solderless, reverseable connection.

Inputs Outputs

Outputs

https://www.facebook.com/HARRYPL0TTER/ Harry Plotter (aka dennis verschoor akak mono-poly, maintainer of worm synth lab), using modular synths to control xy- pen plotters

Shops

Up until a few years ago it was not strange to bike a few minutes to a nearby electronics shop to buy a headphone jack input socket or battery holder. In 2015 the last electronics (component) shop of Rotterdam closed (DIL). Many preceded (2014 Van Der Bend) and many followed, leaving us with just a handful of physical shops to get (unwanted) advice and goods at a premium price without waiting for yellow envelopes from China. Besides not being able to physically examine the goods for sale (will it fit?) more important issues arise. Beyond supporting your local entrepreneur, the decline of DIY shops like the above signify a certain level of consumerism, painfully acknowledging planned obsolesce over DIY repair culture.

Local Shops

Rotterdams Electronica Depot a sporadic electronics shop near you...inquire dennis for more info

https://www.radiotwenthe.nl/ The Hague

https://www.hf-electronics.nl/ Haarlem

https://www.baco-army-goods.nl/ Ijmuiden

http://www.radiopiet.nl/ Arnhem

https://www.tinytronics.nl/ Eindhoven, semi public shop, sells Chinese knock-offs at a premium..

https://www.hobbyelectronica.nl/ Online only, quick delivery, expensive-ish

https://www.kiwi-electronics.nl/ Online only, quick delivery, expensive, recently burned down, sells adafruit stuff etc (expensive-ish)

European Shops

https://www.tme.eu/nl/en/ Member of the Shenzhen (China) Chamber of Commerce. That says everything, please forget box pushers like conrad, farnell, digikey who will rip you off

China

(Almost) EVERYTHING mentioned above comes from Shenzhen, China...so aliexpress.com (or taobao....good luck!). It even pays of to fly to HK, get a SZ port visa and buy what you need in case you want bulk items.

Pads

https://pad.xpub.nl/p/lfp1

Reading/Watching/Listening List

http://www.gieskes.nl/ databending circuitboard designs, owns his own pick and place machine, music on tape, vinyl, concrete and what not.

https://www.ciat-lonbarde.net/ taking modular synths in some direction

http://www.gjp.info/ originally radio amateur drummer, applying knowledge of electronics to make incredible noise

http://www.electronicpeasant.com/ discovered by accident, but most 'personal homepages' of early synth enthusiast will publish in this manner

https://www.mengqimusic.com/ friend from Beijing offers some nice interfaces

https://www.errorinstruments.com/ your local eurorack pusher, love bbq in Shenzhen, has infinite energy to make some seriously interesting devices

https://www.muffwiggler.com/forum/index.php the forum where all the action takes (took?) place. Terrible name, terrible place, all the goods you need, though scattered over 90+ forum pages, enjoy!

https://www.facebook.com/HARRYPL0TTER/ Harry Plotter (aka dennis verschoor akak mono-poly, maintainer of worm synth lab), using modular synths to control xy- pen plotters