Perpetual Chimes is a set of augmented wind chimes that offer an escapist experience where your collaboration composes the soundscape. Since there is no wind indoors, the chimes require audience interaction to gently tap or waft them and encourage/nurture the hidden sounds within – triggering sounds as the chimes strike one another. Since the chimes make little acoustic noise – essentially they’re broken until you collaborate with them.

With this guide I'll show you how I built my interactive musical sculpture.

Supplies

1x Raspberry Pi 3 B
1x MakeyMakey
6x Conductive chimes (copper or stainless pipes)
6x Jumper leads
3D Printer and filament
5m of 1.5mm diameter steel cable
12x steel cable grip

Step 1: 3D Print Your Case

The head unit of the chimes is where the brains are held, so as well as being big enough to hold all the equipment it must also have holes for all your power supply and headphone leads.

Case measurements

I printed mine with a diameter of 150mm and height of 60mm.

Holes to drill

8x holes for support cables (4 in base, 4 in lid) - 5mm diameter

1x hole for "earthed" pendulum in middle - 5mm

12x holes for chime supports - 5mm

1x hole for USB power and 3.5mm headphone cable (in lid) - 15mm

The size of these holes is simple a guide and will depend on the thickness of your cables. You may well need to drill the holes out and make them bigger.

The 3D printer I used wasn't able to print the case in a single pass because the walls were too thin - so we printed in two semi-circle sections.

Step 2: Securing and Supporting the Case

With all the holes drilled, we can now secure the case shut using the cable grips. These same cable grips also support to the chimes.

Drill holes through the top of each chime, around 10mm from the top, depending on their length of course. Thread the steel cable through this hole and then through the holes in the floor of the case. Secure these with the cable grips, placing one end of the jumper lead in at the same time. We'll use the other end to connect it to the makeymakey.

Step 3: Programming

In the last photo you'll notice I added an additional device on top of my Pi, originally I thought the headphone output of the pi wouldn't suffice but in hindsight its actually fine!

As such, all you need programme is the code which triggers the sounds. For my chimes I used Scratch + makeymakey, you can see my code here. Which each chime wired up to be a letter input (using the connections on the back of the board) I simply programmed scratch to randomly pick from an array of recordings I made in Logic Pro X. These were 16 different notes all from a scale I picked.

Additionally, theres a variable counting every time a chime strikes, when this number is a "modulus" (a bit like divisible) of 25 then a BIG bass note plays.

Step 4: Final Assembly

I would recommend setting up your Pi with SSH so you can remote access and make any adjustments, this means you dont have to carry around a screen/keyboard/mouse etc whenever you want to make changes to the code. Alternatively, have some spare SD cards at the ready to swap out if you make any changes.

Once your code is uploaded, and your makeymakey plugged in and wired up (remember, earth to the chime in the middle, and letters to the chimes on the outside) then run the USB and 3.5mm headphone cable through the hole in the lid and secure the box.

When my chimes first went on display I needed an additional loop of cable to reach the beam above, this also meant I needed a 3.5mm extension cable - thankfully this didnt affect the volume and it still worked.

BARE IN MIND. The sound quality of Scratch isnt ideal, in future installations I'm looking to switch to PureData for a higher fidelity sound. But as my first Raspberry Pi project, this more than sufficed!