Category: Builds


Hacking at the summer cottage

A typical mökki (~summer cottage) moment of a hacker.

Act 2: The Spirit of a Real Life Avatar is the second part of a living media project The New Degrees of Freedom by Jenna Sutela with collaborators. The essential part of this performance are ten larynx players that are used in transforming audience members to copies/avatars of the main protagonist (Jenna Sutela). Audience can then witness a dialogue (conceptually more like a monologue) between her and the avatars. The trailer/documentation shot at the art biennial Antagon in August 2013 will hopefully give you some idea.

My task for this project was to design a mobile sound system that would consist of several independent audio players and would allow the dialog to be reproduced in sync with the live speech of protagonist. Basically a bit of hacking, some sound design and a few hours of audio engineering. I’m giving here a brief peek of the final system, but as there is a bit of magic involved I’m not able to reveal all the secrets here. However, below, you will get a glance of the core of the larynx player electronics. Larynx player enclosures are custom 3D prints (semi) accurately modeled after human voice box by Emmy Maruta. We worked closely together to ensure that electronics could be fit and installed to the final print.

Mutilated X-mini MINI II capsule speaker with VS1000 OGG player.

Mutilated X-mini MINI II capsule speaker with VS1000 audio player.

The electronics for this project needed to be cheap, small and mobile. Requirement of mobility means that there has to be battery or accu of some sort involved. When the budget for the electronics is fairly small, usually the best route is to find a product that does something pretty similar you want to be done and hack it. After checking through several products I bumped into product called X-mini MINI II capsule speaker. It is basically a cheap mobile speaker that was able to give just enough volume to match level of loud speech. As it had an inbuilt accu, it had already all the electronics required for loading it. When gutted (and parts of the circuit board amputated in order to minimize the footprint) and equiped with a stamp sized VS1000 Audio module (more info on this at my previous post) it was still possible to fit it into a fairly small enclosure. After the speaker electronics board was reverse-engineered, it was quite straight forward to connect line outs of VS1000 audio player to the inputs of the player and take the 3.8V power — just enough for the player — from the accu. Power switch had to be moved to another location on the board for better accessibility. Of course I needed to make a bunch, which went quite nicely even with minimal amount of tools I had with me at the summer cottage where the final build took place.

Hard work demands sturdy tools.

An old school soldering stand I found under the barn.

Sense Disorder

Sense disorder installed in Helsinki Taidehalli.

Sense disorder installed in Helsinki Taidehalli.

This is an installation I built for artists Paola Livorsi and Hilda Kozári based on their concept. Livorsi is sound artist and Kozári is known for her smell oriented pieces. This piece, to be used in workshops for children, combines these both aspects. The installation itself is a wooden box with four doors. Each door has different color, smell and sound attached to it. In this project I was in charge of industrial and electrical design, programming and carpentry. This explains why this post will be highly technically orientated.

This was the first installation I designed with 3D modeling program SketchUp. The design challenge here was to come up with design that can be put together with minimal amount of tools and with a minimal budget while still creating something fairly professional. After initial design I took the measurements to woodware shop and took a pile of ready cut plywood pieces back to my shop. After two days of glueing, drilling, sawing and painting the box itself was ready.

Each door has a small magnet embedded to them. Magnet is triggering a reed magnet switch that is read by a custom built electronic player board. Board consists an Atmega328 microcontroller that is controlling four VS1000 audio modules. Microcontroller was programmed with Arduino IDE. I could have used computer with multichannel sound card, but as the application was fairly simple, building a stand alone audio player from scratch makes more sense. Compared to a computer it is cheaper, boots immediately and is more robust.

VS1000 audio modules are quite nice alternative to Wave Shields or MP3 Player Shields commonly used with Arduino in applications such this. First of all, the price: at 16€ or cheaper they are way below the prices of neither of the alternatives. Audio wise VS1000 is able to output CD-quality stereo signal, something that Wave shield is not able to do. VS1000 module also is equipped with different outputs for headphones and amplifiers. MP3 player shield you cannot connect straight to external amplifier without additional circuitry. Another nice thing is that the source code of the firmware is available (although not open source). This allows you to modify the player functions, or even implement your application with VS1000 module alone as it has an array of I/O pins itself. Interfacing with ATMega328 can be done using UART serial connection (Though I needed to bring down the default baud rate from 115200 as SoftwareSerial library is not really able to read data stream that fast (wonder why this has not been documented anywhere)). I needed to use SoftwareSerial as I wanted to use only one microcontroller for controlling all four players. Last thing to mention is that one can update the firmware and even use the memory of VS1000 chip as a tiny harddrive to store audio files. Updating can be done easily by using the memory card, no external hardware is required. If internal memory of the chip is not enough, audio can be read from memory card instead.

Installation behind the scenes. The main logic board can be seen behind the light bulb at the left.

Installation behind the scenes. The main logic board can be seen behind the light bulb at the left.

The box will hide two pairs of cheap computer speakers, giving each door its own speaker. This way we are really able to bind audio to a single door. There is also two energy saving lamps installed inside the box to allow the colors of filters installed on each hole to become visible. The electronic player card can be seen behind left lamp. For the smell, essential oils are applied to tiny pieces of felt that are hidden in the space between the doors and color filters (not really visible in this shot).

Arduino code for the AVR can be found here.

Improvized super cluster setup in Coachella © Jenna Sutela

Improvized super cluster setup in Coachella © Jenna Sutela

Super Ball is a large scale balloon installation I was working on together with Jenna Sutela and Martti Kalliala based on their concept. Their initial idea was to animate a super sized balloon taking three giant leaps in the night sky. Installation was made for Coachella festival 2008. However, hostile wind conditions at the location made the implementation of the original concept impossible and Jenna and Martti cleverly refactored the installation into Super Cluster. I´m hoping that in the future the installation can be displayed in the Super Ball form, which it was designed for.

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Improvized super cluster setup in Coachella © Jenna Sutela

For installation my task was to implement a control unit for controlling a network of 49 1-Wire switches. The network itself was put together by Jukka Rehu. Each switch is basically a programmable microcontroller. In this application it was not necessary to actually program them, just alter value of one output pin on the chip. This would turn ultra bright LED connected to it on/off.

Finished Animator Unit. Knob may be used to control the speed of the animation. Buttons are used for selecting different animations.

Finished Animator Unit. Knob may be used to control the speed of the animation. Buttons are used for selecting different animations.

This was one of the first projects I used Arduino (first generation). Electronics were installed in a Hammond box. There are connectors for power supply, fuse, USB (so there would not be any need to open the box for re-programming Arduino) and for light chain itself. Below one blurry picture from the inside.

Animator unit contents. Those were the times of messy wiring.

Animator unit contents. Those were the times of messy wiring.

Luckily there is a ready made library for 1-Wire protocol. 1-Wire protocol is pretty straight forward but the command api of a switch was not. After some struggling I finally understood the order on 1-Wire commands to make the LED blink.

Super Ball network test run without balloons attached.

Super Ball network test run without balloons attached © Jenna Sutela

Testing the controller with the chain was a nightmare. It took hours of me to realize that innocent looking loops on a 150m light chain cable were actually forming coils which blocked the data stream inside the cable. The last switches in the chain were behaving badly and sometimes the whole chain could freeze.

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When network cable was not fully unwrapped, the data communication problems occurred © Jenna Sutela

I added more code for error checking but when we finally did spread the cable more straight in Jenna’s studio, the chain started to behave. On the video above you see the before behavior as two LEDs are on at the same moment. In retrospective, dividing the network to two networks each being significantly shorter than 150m would have helped a lot as well.

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When network cable was unwrapped, the data communication was working fine © Jenna Sutela

Designing and building the light chain part of the installation (1-Wire network, led-units, balloon valves etc) was done by Martti Kalliala, Jenna Sutela and Jukka Rehu.