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Wolfgang's Residency Archive

U.F.O. (Under the FlyOver)

by Yashas Shetty and Wolfgang Spahn

Under The FlyOver at Maximilian Forum Munich (2017)

As part of Double Road 2017 (Germany meets India), filmed by Fabian Hesse, supported by Goethe-Institut, and the city of Munich (Kulturreferat) and Indian Sonic Research Organization (ISRO).

AGAINST any monolithic definition of beauty

AGAINST quantifying success in any way possible

AGAINST giving space to neoliberalism in subculture

A meeting. A laboratory. Sounds from Indian tribes influenced by western radio music and sounds of Kraut musicians from Bavaria that traveled to Bangalore in the 70s. Surprise collaborations between subcultures. On the menu : Live performances and DJ sets that comment on cultural exchanges in a post-colonialism world.

Under the FlyOver under a flyover in Bangalore

Yashas Shetty, Shreyasi Kar and Wolfgang Spahn (2016)

With support of Goethe-Institut Max Mueller Bahvan Bangalore, Jaaga and The ISRO.

Under the FlyOver - Schloss Solitude (2016)

With support of Akademie Schloss Solitude.

Under The FlyOver at Gallery Palermo, Stuttgart (2016)

Filmed by Antoni Rayzhekov, with support of Akademie Schloss Solitude


Paper Bits is a small, modular synthesiser system voltage controlled, created by Wolfgang Spahn. The start was at the Art Science BLR and the Indian Sonic Research Organization with support of Goethe-Institut Max Mueller Bhavan in 2016.

Its further elaboration was done with help of Angelo Thomaz, Ioana Vreme Moser and many many more.

Its simple design, accessible interface as well low price, offer a powerful sound tool dedicated to learning, experimenting, and playing.

Currently, there are 19 modules online that can be put together in different ways and patched. However the system is growing and changing as we are currently working on it.


Here you find the “stl” files for the Paper Bit Frames:


All filters and oscillator use the OpAmp LM358. But for a better sound and a better peap to peak range one can use the rail to rail OpAmp MCP6002-I/P or the TLC 2272. And instead of the LM324 the MCP6004-I/P or the TLC2264.



PB101 Sync VCO

PB104 Wien Bridge

PB105 Saw Sync

PB106 VC Oscillator

PB107 Sync VCO II



PB201 Step Sequencer

PB204 Sync Sequencer

PB206 Sequence (Total) Recall

PB202 MIDI to CV

PB203 IR Terminator


PB401 VC Echo

PB701 Electric Intonarumori

Power and Output

PB301 Power Board

PB302 Audio Output

PB311 Power Brick

PB321 Supply Unit


PB702 Midi Synth

PB703 Pick Up

PB705 VCCC (Voltage Controlled Chua Circuit)

PB808 Kick Drum

Euro Rack to Paper Bit Adapter

For Developing and Indication

PB303 Level Meter

PB303 Bread Bit

How to Patch

Paper Bits have two power lines for +5V and the ground and three connectors for the signal, two general busses and one gate bus. Every module several in and outputs. With jumper one can select them to connect the module to the bus or send the signal through without effecting the module or the signal.

All in and output can also be connected via patch cables at the in and output instead of the jumpers.


These boards are designed by Wolfgang Spahn 2016-20.

They are licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License.

Pop Neuron - An Analog Artificial Neural Network

The Analog Computer Confetti is a modular system that makes it possible to perform all kind of computations and operations on base of electrical voltage.

Pop Neurons are special modules to implement an analog artificial neural network into the multi-connect system of the Confetti. Both systems have been and still are designed by Wolfgang Spahn, the Confetti system since 2015 and the Pop Neurons since 2017/18.

The Analog Computer Confetti was used in combination with nearly 100 Pop Neurons for the installation Symbolic Grounding by Christian Faubel and Wolfgang Spahn. Also, the analog computer was key for the installation Strange Attractors by Wolfgang Spahn.

The analog computer Confetti was first presented at the residency at Art Science BLR and the Indian Sonic Research Organization at a Srishti Institute of Art, Design and Technology, courtesy of Goethe-Institut Max Mueller Bhavan in 2016.

The development of the Pop Neurons was supported by Künstlerdorf Schöppingen in 2017, where Christian Faubel and Wolfgang Spahn conducted preliminary work.

Explaining the Circuit

The roots of the Pop Neuron lies in the bicore oscillator used by the BEAM (Biology, Electronics, Aesthetics, Mechanics) robotic group for their BEAMbots. This bicore oscillator is a classic Schmitt-Trigger oscillator, with all components used twice.

With each Pop Neuron one can build one half of this circuit by plugging in the resistor-capacitor components to the board.

Some characteristics of the Pop Neuron design are the use of “pure” analog components. For example to avoid “digital” CMOS chips in the analog computer Confetti the Schmitt-Trigger (respectively the inverting Schmitt-Trigger) is build out of OpAmps similar like the Confetti Schmitt-Trigger and the Confetti Inverting Schmitt-Trigger boards. The TL072 chip that is used in the design of the Pop Neuron includes actually two OpAmps. This second OpAmp is used as an extra input buffer circuit.

The option to plug a Resistor-Capacitor-Circuit with different values in the sockets of the board - like used in many other designs of Confetti modules - makes the Pop Neuron more flexible to use in all kind of applications.

Thus one can use the Schmitt-Trigger in combination with the plug-in slots of the Pop Neuron module to create an analog neuron. In adding resistors and capacitors to it one can build an excitatory or an inhibitory neuron out of a Pop Neuron 001 module, depending on the jumper setting.

The Pop Neuron 002 and 003 can be used in the similar way, but they have a prefixed behavior setting, i.e. they are always excitatory or inhibitory.

The core ides of the analog computer Confetti was to provide a highly flexible system for using and combining all individual boards of this system. One can patch all modules via a build in bus or in using the patching wires in combination with the sockets on the boards. With these ideas also realized in the Pop Neuron, one can easily use two different neurons to build an oscillator, or with some more neurons one can build a whole analog artificial network.


These oscillator and network behave similar to the one described in Dynamics of Pattern Formation in Lateral-Inhibition Type Neural Fields by Shun-Ichi Amari. The implementation of the analog neuron was described in Implementation of Artificial Neural Oscillators in 2009 by Pavlo V. Tymoshchuk, Yuriy I. Paterega.

Like already mentioned one important origin of the Pop Neuron is the bicore circuit of the BEAM.

A digital implementation on syncing and desyncing processes of two mutually coupled systems one can find on Netze/Networks Neural Oscillators by Lab3 - Laboratory for Experimental Computer Science at the Academy of Media Arts Cologne.

An other example of an electric implementation of an analog neuron for controlling robots one can find in Neurodynamische Module zur Bewegungssteuerung autonomer mobiler Roboter by Manfred Hild.

Neural Sound Synthesis

One can use these neurons to generate pattern and structures for all kind of sequencers and also for synthesize sound for musical instruments similar like the one David Tutor used for his Neural Synthesis Nos. 6-9 in 1993. A description of his work by Forrest Warthman and Mimi Johnson is on the artist web-side: The Neural Network Synthesizer. His neural synthesizer was based on a RC-circuit in combination of the 80170NX Electrically Trainable Analog Neural Network chip by Intel.

For the installation Symbolic Grounding Wolfgang Spahn designed a musical instrumental synthesizer with Confetti and Pop Neuron modules.

The Confetti Neuron

Because the Pop Neurons have some fundamental problems when it comes to use in audible realm Wolfgang Spahn designed a complete new board in 2019, the Confetti Neuron.

Some of the problems were for example the much to high power consumption of the Pop Neurons. That leads regularly in hear able voltage fluctuations every time some other neurons - beside the ones one wants to listen - started to fire. An other problem were the big capacitors one had to use in the RC-circuit. To get some nice low frequency oscillation one needed sometimes 2000µF capacitors or higher. And an other serious downside of the Pop Neurons were the ugly shaped capacitor charging curve - that's a bad precondition for nice sound synthesis.

And also the theoretical model of the Sun-Ichi-Amari neuron demands for an internal feedback and that is missing in the Pop Neuron.

These problems are solved with the design of the Confetti Neuron and the new board also comes with some more benefits like an extra output for the nice triangle wave that one can use for audio signals and the need of just one jumper to set the behavior from excitatory to inhibitory.

All other Pop Neuron boards also have a newer and better equivalent in the Analog Computer Confetti.

All Pop Neuron boards are obsolete!

Use the Analog Computer Confetti boards instead.


For connecting the Pop Neurons one can use the bus on all boards or just use patching wires. Certainly, a combination of both is possible.

For a neural oscillator the output of one neuron has to be connected to the input of the other, and vice versa.

Because one can use multiple input and output connections more complex networks can be build. The Confetti302 Breadboard could be quit helpful for doing so.


All Pop Neuron boards and modules are obsolete!

Please use the Neural Network Modules of the Analog Computer Confetti

PN001 Pop Neuron

PN002 Excitatory Pop Neuron

PN003 Inhibitory Pop Neuron

PN012 Excitatory Pop Neuron 2

PN013 Inhibitory Pop Neuron 2

PN101 Opto Synapse (Osc)

PN102 Opto Synapse (Trig)

PN103 Fire Amp

PN104 Inter Neuron

PN201 Turn Connector

PN202 Connector

PN301 Energy Supply

The PCB version of the PN001 Pop Neuron the Pop Neuron Shenzhen Ready on

Made by Marc Dusseiller and the SGMK.

Confetti - An Analog Computer

The Analog Computer Confetti is a modular system that makes it possible to perform all kind of computations and operations on base of electrical voltage.

This stack able modular electronic analog computation system was and is still developed by Wolfgang Spahn since 2015.

The analog computer Confetti was further developed and presented at the residency at Art Science BLR and the Indian Sonic Research Organization at the Srishti Institute of Art, Design and Technology, courtesy of Goethe-Institut Max Mueller Bhavan in 2016.

The analog computer was key for the light and sound installation Strange Attractors by Wolfgang Spahn where he “calculated” a Lorenz System to modulate an other Lorenz System.

Confetti was the basic brick in the installation Symbolic Grounding by Ch.Faubel and W.Spahn.

And it was the core of the Installation Echo State Network, an analog neural synthesizer network build out of 150 Confetti Neurons.

Usage and Patching

Each module can run one operation, some boards together can be used for analog computing, designing synthesizer and all other kind of analog electronics.

For connecting the Confetti modules one can use the bus on all boards or just use patching wires. Certainly, a combination of both is possible. The connection boards are helpful for putting together a lot of boards.


The in- and outputs can be patched with normal breadboard patching wires. It's manly based on the operational amplifier TL072 and the operation voltage is 12V/-12V.


The analog computer was inspired by the articel “Die Chaos-Maschine: Analoge Computer wiederentdecken” Elector Magazine 09-10/2011 by Maarten H. P. Ambaum and R. Giles Harrison (Department of Meteorology, University of Reading, UK).

Further information and wiring examples one can find in the old manuals of analog computer of the online library of the Analogmuseum:

Analog Artificial Neuron Networks

One can implement analog artificial neuron systems in the analog computer with the Confetti501 Confetti Neurons as well as with the outdated boards of the Pop Neurons.

Confetti Modules

Neural Network Modules:

Confetti501 Confetti Neuron

Confetti502 Analog Junction

Confetti503 Digital Junction

Confetti504 Quad Indicator Buffer

Confetti505 End Stage

Confetti506 Monostable Pulse

Pop Neuron (obsolete)

Standard Operational Modules:

Confetti701 Absolut Value

Confetti702 Differential Amplifier

Confetti703 Multiplier

Confetti704 Non Inverting Summer

Confetti705 Inverting Integrator

Confetti706 Non Inverting Scaling Amplifier

Confetti707 Inverting Scaling Amplifier

Confetti708 Inverting Summer

Confetti709 Differentiator

Special Operation Modules

Confetti101 Gyrator

Confetti102 Chua'S Diode (with two diodes)

Confetti116 Chua's Diode

Confetti105 Instrumentation Amplifier

Confetti106 Quad Buffer

Confetti107 Inverting Comparator

Confetti108 Non Inverting Comparator

Confetti109 Schmitt Trigger

Confetti110 Inverting Schmitt Trigger

Connection Modules

Confetti302 Breadboard

Confetti303 Turn Connector

Confetti304 Connector

Confetti305 Simple Connector

Confetti310 Hexacorner

Confetti311 Hexaconnector

Confetti311 Hexaconnector II

Power Modules

Confetti003 PowerBrick

Confetti 9V Battery Supply

Miscellaneous Modules

Confetti103 Buffered Output (for audio output)


These boards are designed by Wolfgang Spahn 2015-20.

They are licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License.

Creative Commons License

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