Joel holds a Blurring the Boundaries board with crocodile clips attached.

This post is a work in progress and will be updated as we are able to upload new footage from our archives…

Our frequent collaborator and newly appointed project partner Joël Dazé has been getting to know our custom boards following a brief development session last year.

The result: the beginnings of a new instrument he calls the Octobox, featuring eight light sensors currently mounted to a cardboard box as a chassis. Shining light onto each sensor fades in the sound of a musical note through a website.

Joël has plans to create a custom chassis to make this a more permanent instrument, but it also represents a prototype and conversation-starter for future sensor-based instruments to be developed in workshops.

Assembling the Octobox

You can check out some of Joël’s development footage in the video below.

Video access: closed captions in English, currently no audio description.

Scene: Joel’s workspace featuring a desk with a cardboard box, a circuit board around the size of a mobile phone with holes in the shape of figure of eights to enable crocodile clip connections, and eight light sensors connected via crocodile clips.

If you’re interested in finding out more or would be interested in hosting a workshop using this kind of approach, please leave a comment on the YouTube video.

Remote music making with the Octobox

The circuit board sends out MIDI by default, which means it can either trigger musical notes or move virtual faders. At Blurring the Boundaries, we tend to gravitate towards the kind of expression you can get from a continuous control, meaning that our default is to map the intensity of light from a sensor to the dynamics of a tone — making a digital equivalent of perhaps a violin bow or a theremin, rather than a piano.

Since we started our work during the pandemic, we’ve also become accustomed to controlling music through the browser, and it’s just as natural for us to send information over the internet as it is to make sound in the same room. This also means that although we’re located in different cities, we can continue developing the software side of the instrument in between our in-person meetings.

Here’s a quick clip from one of our remote development sessions, in which each light sensor in Ottawa controls the volume of an individual note on a computer in Montreal.

Video access: closed captions in English, currently no audio description.

Scene: a messy desk featuring a screen with Charles and Joel on a Zoom call, alongside a website with eight coloured boxes that respond to the volume of eight musical notes. Joel is shining a flashlight into an array of light sensors, while Charles is editing code in another window.

Under the cardboard hood: the Blurring the Boundaries custom boards

The circuit board used to gather information from the sensors is a custom PCB we have been working with for the last few years. Like Joël, we’ve been using these in workshops as the heart of various prototype musical instruments, with light sensors, arcade buttons, faders, dials, joysticks, and other components. The typical approach is to prototype as quickly as possible by raiding our recycling for supplies on the way out — cereal boxes, tin foil, and poster tubes are firm favourites — and cutting holes to insert the sensors and mount the circuit boards. The next step (unless cardboard is preferred, which is of course perfectly valid!) can be to replace the crocodile clips with soldered connections, and move the housing to 3D printed or laser cut enclosures. At this point, the design can be refined, and the sensors can be fine-tuned or replaced. Depending on the boards used inside a given project, the whole instrument can be self contained with an internal synthesiser or sampler connected to an audio jack or a built-in speaker for around $200. For a more cost-effective solution (as affordable as $20 in some cases), a USB cable or Bluetooth can connect to a computer to create a MIDI controller.

The hands of a visitor to the exhibit turn dials on a cardboard box with an embedded set of dials, cables and arcade buttons.
“Hidden Sounds” end of year exhibition at City Lit, London in 2018, featuring student-created instruments with Bela inside.

Our approach was inspired by open source off-the-shelf solutions like the Bare Conductive Touch Board and the MaKey MaKey, which both feature access points for crocodile clips or banana clips…or even conductive thread and paint, to trigger events on a computer. In the case of the MaKey MaKey, this enables an on-off, whereas on the Touch Board, it’s possible to measure a continuous movement from a capacitive sensor (a bit like having twelve theremins at your disposal).

These boards are particularly great for education and rapid prototyping of musical instruments. Our aim is to get practical and experiential with playing straight away, as much as demystifying the technology. And in the spirit of “blurring the boundaries”, we’ve found the most engagement through a fluid hands-on approach to sculpting the physical object, be it out of tin foil or cardboard, helps build ownership, understanding, and that all important sense of play. Having simple crocodile clip connections enables us to focus on what you could describe as a more access-oriented way in to building a custom instrument…how it’s shaped, how you interact with it…hopefully challenging expectations around the emphasis on technicality over musicality and personality.

But it’s a bit more complicated to connect something less conventional like a light sensor — it involves creating a circuit known as a voltage divider, and while this is one of the simpler circuits out there, there are already a few potential barriers as we ask musicians to start getting to know bread boards and resistors before we can even make a sound. Not to mention juggling eight of those. The result? Well, maybe we’ll be making music at the end of a weekend-long workshop…and guests often come away thinking they need a degree in electronics to make something outside mainstream solutions.

So we wanted a board that would provide the same crocodile clip connections to measure analog signals from these sensors, so we went ahead and created our own “shields” to fit on top of existing boards. Our boards can currently be used with Arduino, Micro:Bit, and Bela. Please get in touch if you would like to check them out — we are currently in the process of making the source available.

A black and white circuit board features flowing line art of artists' faces merging with abstract shapes, with the blurring the boundaries logo at the centre. Around the edges of the board are eight sets of two "figure of eight" shaped holes to accomodate crocodile clips.
The board used in the Octobox features a printed collage of line-art to bring personality to the circuit, including images of John Kelly, Robyn Steward, and other collaborating artists.

The boards feature artwork, including representations of ourselves and collaborating artists in the studio — our way of emphasising that this technology is a means to make music, to communicate…and that while we’re connecting sensors, the human connections are the most important….

A wooden box holds a custom circuit board with holes for crocodile clips to attach sensors. Around the box sit instructions for coding the musical element using the Pure Data graphical programming language.
An early version of our kits featuring a Rasperry Pi for sound, which Charles Matthews and Gift Tshuma put together in collaboration with MilieuxMake at Concordia University in 2019 for a short run of workshops. The accompanying instructions show the Instrument Maker library developed for Pure Data.