Singing Toilet

By Nicola King. Posted

It may be the ultimate bathroom experience: wall-mounted toilet rolls that ‘sing’ various notes when the paper is pulled, thus creating an extremely pleasant and calming trip to the smallest room. But how did this very novel idea come to fruition?

Maker and artist Max Björverud explains that this custom installation was born from a request from a client: “Fredrik Öst at Snask (a creative agency) here in Stockholm wanted something for the toilet. I don’t remember how our conversation really panned out, but a week later I presented the first prototype. The build itself was quite quick, but it needed some iterations to find the best holder and roller. The most difficult part was to make it usable. They need to be able to switch toilet paper without a technician.”

You gotta roll with it

The system is built around a Raspberry Pi, a HiFiBerry AMP to output high-quality sound to a hidden speaker, and an Arduino Mega to take readings from eight Hall effect sensors. In each toilet roll holder, a 3D-printed part contains a circular four-pole magnet that triggers the Hall effect sensor when rotated. Whenever it receives data from the sensors via the Arduino, Raspberry Pi outputs the respective sound sample for each moving toilet roll.

“As long as a roll is rolling, the Arduino will send a continuous message telling the Pure Data patch to play that specific sample,” says Max. “It’s built in such a way so that the voice will sing as long as the roll is rolling.”

A 3D-printed part on the end of each roll holder contains a circular magnet that triggers a Hall effect sensor on the left when rotated

A few technical issues were encountered in the build process, including random instances of failure to work: “My audio patch (program) consumed 100% CPU and clogged the whole Raspberry Pi,” recalls Max. “That version used windowing functions to create seamless pitch shifting of the samples I used for audio playback. Had to abandon that…”

Max also had to fiddle with the Hall effect sensors for quite a while before he was happy with their placement, and a colleague assisted with the 3D prints, but all their efforts proved worthwhile.

When it comes to changing the rolls, this is just done normally and the only thing that people need to remember is to put the roll back in the correct direction: “The magnets inside the 3D print must face the Hall effect sensor on the left.”

Flushed with success

While Max has had great feedback on his creation, “there hasn’t been much interaction since people are out of office nowadays. I’m currently learning how to play it so I can hold toilet concerts.”

Raspberry Pi, HiFiBerry AMP, and speaker are placed in a wooden box, along with an Arduino Mega connected to the sensors

Integral to the Singing Toilet, and to all his work, has been Raspberry Pi. “[It’s] my go-to tool for interactive audio, mainly because I’m so used to it, but also because there’s such a great community where any help needed is out there to be found,” Max tells us. “My past projects with Raspberry Pi include a huge dance carpet, a synth made of steel, museum exhibits, and various interactive audio projects.”

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