blog :. joão costa

@ Interactive Telecommunications Program

project development studio : fabrication update

For the last couple of weeks I’ve been working on the fabrication of the instrument. I have two modules fully assembled and working as expected. Since I have all the pieces for the modules ready, now it is only a matter of assembling each one of them.

Right now I’m working on the mount for the modules. I thought of making stands out of steel rectangular tubes and wood. Each stand will group five modules, therefore preserving the mobility of the project.

– Below are some pictures of the two modules and some renders of the mount –

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project development studio : update

After figuring out the dimensions I’ll be working with, I bought the final wood, which is Poplar, and started working on the CNC router. I’ve done ten out of twenty pieces of wood. This week will be dedicated to fabricating the wheels that’ll hold the horsehair and play the strings. Also, I’ll be trying some different finishes for the wood pieces.

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project development studio : quick update

For the past two weeks I’ve been working on a prototype on the CNC router with 2″x3″ pine studs. Right now I am trying to figure out the correct dimensions and measurements so I can move on and build the final system.

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project development studio : update

I have finally defined how the instrument will look like. I’ll be working with a modular installation consisting of twenty modules. Each one of them will have two guitar strings, making it a forty strings total. I think working with modules will end up being a good choice since, as soon as I figure out how to build one, I’ll just need to replicate the others.

At first I thought of having the motor on top of the guitar pickup to cause the interference I experienced on my first experiment for NIME, but I soon realised this could cause too much confusion as I’ll be dealing with twenty different motors and pickups, so I might move the motor to a different position in order to get a clean sound. The pickups will be connected to a mixer and to an analog reverb pedal.


I built a prototype to get an idea of the dimensions I’ll be working with. This will help me sketch out a file for the CNC, and also to visualize the placement of all my components.


Prototype |


Later, I’ll add a switch for the motor, and a pot for the pickup.

Wheel and horsehair |


I’m coming up with a solution for attaching the horsehair to the edge of the wheel that’ll be fixed on the motor.


project development studio : update

I find it really challenging to fit my project in questions like ‘what?’, ‘why?’, ‘for whom?’ and ‘how?’. I think of it as a challenging exercise because of the context and concepts which I often work with. The public, even though plays a big role in this context is not, by any means, the target of my work, or even for whom I design for. All the work that I do sort of feel like silence – and here I face silence in two ways that constantly merge. First I cite what Italo Calvino said about nothingness in his Six Memos for the Next Millennium ‘The poetry of the invisible, the poetry of the infinite unpredictable potentialities, are born from a poet that doesn’t nourish any doubt regarding the physical characters of the world’. Secondly, I’ll quote Susan Sontag in her Aesthetics of Silence: ‘Silence is the furthest extension of that reluctance to communicate, that ambivalence about making contact with the audience which is a leading motif of modern art, with its tireless commitment to the “new” and/or the “esoteric”. Silence is the artist’s ultimate other worldly gesture; by silence, he frees himself from the servile bondage to the audience, antagonist, arbiter, and distorter of his work.’ (By the way, this touches on the conversation we had last class on how Ryoji Ikeda chooses to not discuss his work). Taking into account these two statements, I hereby position myself as someone who articulates those two definitions and will humbly define me, for now, as a poet of silence.

The choice of not communicating, of this state of silence, although may seem so is not a synonym for inertia. It is keeping the animal state, as Deleuze would say, of being in the lookout. A wild detective of the world. Trying to articulate subjects that have this potential of existence, of being, that without the artist’s perception would be unnoticed.

Regarding some of the critiques and feedbacks given during our sessions, I was able to notice that many of the viewers of this work in progress would argue that the concept that touches on the Mongolian history, Genghis Khan and the choice of using Mongolian horsehair should be, in some way, more explicit; something more than the title and description. I have considered those comments carefully, but what I honestly think is that the viewer, in most cases, have an aversion for researching and reading about the work, they usually want the concept expressed in its entirety right there, so they won’t have any homework to do. In Portuguese there’s a saying that I’ll poorly translate and use here – most of the public wants the artist to do all the ‘chewing’, so they can only ‘swallow’ the work. What I believe is that the act of ‘chewing’ should be played by both parts; the artist definitely creates a space in place and time where the process can begin its exchange process, something that Nicolas Bourriaud named an insterstice (the exchange domain), but the public should create a new layer of knowledge and ask themselves what is the right way to “””consume””” a work of art – since it is usually consumed as some other kind of product. The approach needs to be reinvented, and the projection most have of the artist as someone who is paying some kind of debt or working as an employer of the public needs to end. The public in a general pale acts on the artist’s position, but this shouldn’t be done in a commercial-like attitude. The pondering must come from the artist’s process and not by a public demand of will.


After my brief rant I will try to answer the questions I see myself facing right now:


A musical instrument/installation that is a metaphor of Genghis Khan’s funeral.


Projects come to me in a rhizomatic way that everytime I fail to define. I honestly don’t know why I do what I do, but I don’t think this is a pejorative thing. I feel like the state of uncertainty and of constant questioning could be the answer to this question.


After some experiments, I can see clearly now that the project will follow the leads of the first prototype, borrowing some characteristics of the others. That said, I will build an instrument consisting of forty strings being played by motors with wheels covered by horsehair. I still don’t know if i’ll have one motor per string, or if two or more strings will share a motor.  I’ll keep using the guitar pickups and will definitely try to incorporate the interference caused by the placement of the motor on top of the pickup. Another thing that still need to be defined is the input I’ll be using. I thought of having some kind of proximity sensors, or sensors that detect footsteps (or maybe both) in a way that various people could play the installation simultaneously. I enjoy the idea of not giving total control to a single individual.

I have been thinking of creating four modules of ten strings. I could experiment with different strings, each module would have a different instrument string. eg.: violin, cello, viola, upright bass, etc. This would contribute for the creation of a big soundscape. I still need to define the proportions and the form of the modules though.


Schedule and Milestones


07 – 14 |

work on what is missing for the concept.

define input.

sketch and define formal aspects.

generate prototypes / consider different scales.

14 – 21 |

work on a solid prototype for midterm / maybe one module.


work on final instrument.


09 |

present instrument.


videos and pictures of the last week’s experiment.

It consists of a metal box with a vibration motor attached to the bottom plate. As a capacitive sensor is touched, the motor increases the amount of vibration, consequently vibrating the metal plate. On the other hand I hold a guitar pickup that reacts to the vibration of the metal plate and the proximity to the motor. By changing the position of the pickup I can vary volume, by changing the amount of vibration I can change the pitch, and if I place the pickup really close to the plate without touching it, the magnet inside the pickup starts to resonate with the plate making it vibrate even though the motor is not vibrating, in that way I create beautiful harmonics!



homemade hardware : first board

For my first board I decided to make the bootloader shield we’ve made in the previous weeks. Since I’ll probably be using this shield a lot, I thought making it look nicer than the one in the purfboard would be a step forward and a great exercise for learning how to use the OtherMill. At my first attempt I noticed that the OtherMill software ignored some of the routes I’ve made on the Eagle file, so I had to change that to make sure the software would mill all my paths. After the second run it was good to go; just soldered the components and it was done!

Finished board:

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EAGLE file:

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project development studio : update

This past week I worked on the second instrument for NIME. After observing the effect that the DC motor had on the guitar pickups, I decided to incorporate that in this second prototype. So, for this one I didn’t use any strings to produce sound. By altering the speed of the motors I realised the pitch of the sound changed, so I thought it could be fun to experiment with various motors – four in total – over pickups. In the end I had four pairs of motors and pickups  connected to a simple transistor circuit and to Arduino. At first I thought of controlling it with an interface made of wood and horsehair attached to vibration sensors, but that didn’t work at all, so I changed it all to potentiometers.


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homemade hardware : 2-3

Last week’s circuit turned into an schematic on Eagle.


And the homemade Arduino bootloader shield! I got the wrong crystal oscillator though, will change it as soon as possible.


project development studio : the funeral of horses

It all started with the proposal of creating a musical instrument and performing with it. At first, I was into Deleuze and Guattari’s A Thounsand Plateaus and their concept of rhizome. The idea, back then, was to come up with what I perceived as a “rhizomatic instrument”, that would have various points all connecting with each other, thus embracing the flux of information of a rhizome and overcoming the necessity of a root-like flow of information and actions. I wanted to add an organic factor to this project and my first thought was to bring silkworms into the mix and have it as the agent that would play the instrument.  But as Bachelard stated in his Air and Dreams, “imagination is, beforehand, the faculty of deforming the images provided by perception, it is, above all, the faculty that frees us from the first images”. Therefore I started to distort what I had, attempting to create a somehow controlled chaos in order to extract something from it. By then, I have been intrigued by the possibility of using a violin or cello bow in the mechanism of my instrument. In a rhizomatic way, I found myself deep into the history and origins of bows.

That lead me to the Mongol Empire – since most of the horsehair used in bows are from the mongolian horse – and to Mongol culture. It happens that the mongolian horse is of extreme importance in their culture. It is traditionally said that “a Mongol without a horse is like a bird without the wings.” Horses are the centre of various spirituals beliefs and has longed played a role as a sacred animal. It is used not only as means of transportation but also as a source of food. The Mongol horse is featured in many songs and even an instrument named Morin Khuur (or horsehead fiddle) was created after it.  In this case mare and stallion are represented by the two strings on the instrument, which were in the past made of mare and stallion horsehair respectively. And according to Columbia Professor Morris Rossabi’s article “All The Khan’s Horses”, Genghis Khan success was only made possible by the idiosyncrasies of the horses in Mongolia. But there is an specific fact that really took my attention.

Mr. Rossabi in his article says that at least forty horses were sacrificed and buried along with Genghis Khan. It is common to sacrifice the steeds after their owner has passed away so he will have a ride in the afterlife. That made the connection I was looking for: it had a symbolic meaning that might make the work interesting and more relevant; it was the step I was missing. The idea is to make an instrument composed of forty strings to play the song in this funeral of horses. Various references and inspirations have appeared since then, such as the mechanism of Leonardo Da Vinci’s Viola Organista, that uses horsehair in a wheel to make a gesture of infinite bowing; Sigur Rós sound aspects when Jónsi is playing guitar with a cello bow, such as the enormous amount of reverb; Andy Cavatorta’s Violina mechanism; among many others.


My main goal this semester is to combine all my classes and make one big project: the final musical instrument for NIME (New Interfaces for Musical Expression). This week I have made the first one-week instrument prototype, which consists of two violin strings being played by a motor with a wheel covered with horsehair. A serendipitous discovery was made when I  placed the motor over the humbucker pickup I used for amplifying the sound of the strings. The magnetic fields from the motor and the pickup caused an interference that made a creepy sound that I ended up enjoying. That was nice.

homemade hardware : week 1

For this week’s assignment we had to burn the bootloader on the ATTiny85 using the Arduino Uno as the programmer. The steps were pretty straight forward. It is cool to know that we can now reduce even more the size of our projects. I thought the Arduino Pro Mini was the smaller we could get on DIY projects, but with the ATTiny85 you can get the bare minimum of the Arduino to run your sketches. There are a few limitations though – it’s not the best tool for rapid prototyping, it is more useful when you have a project done and just need to make it small; that said, it doesn’t allow the monitoring via serial, which makes tweaking parameters challenging; it also doesn’t have support for a few of the Arduino IDE commands, such as the tone syntax. Other than that, it works perfectly and I’ll definitely incorporate it in some of my projects.

First I uploaded the Blink example from the Arduino IDE, just to make sure it was working properly.

Then I built a simple circuit using and LDR and a small speaker, and started messing around with the delay in the end of the sketch. Note that I couldn’t work with the tone command as I said before, so I just used the analogWrite for experimenting purposes.

Lastly, I disconnected the Arduino as a power supply and hooked up a 3.7V LiPo battery I used last semester for the Energy class and.. now it doesn’t need to be connected to the computer/Arduino!