I spent part of the weekend playing with my kalimba prototype. You may have seen it at the end of my Instructable “Designing for Ponoko Laser Cutting With SketchUp and Inkscape (a study in cubes)“.

A kalimba is a percussion class of instrument, originally from Africa, which has evolved to suit different cultures in modern time. My particular evolution is a laser cut design – and I’m playing around with a C-major tuning at the moment (although I am finding improvisation in this key boring).

I started off with the plain box that you see below. It’s an oversized design so that I could play around with the placement of tines, bridge, the tuning and have lots of room to hand drill the holes I needed. The design has been laser cut from 6mm Eurolite plywood, and doesn’t need the small screws that you see to stay together. However, the screws do aid in rigidity and the vibration of the sound box.

Not knowing much about what materials would work for tines, I decided to repurpose a rake – cutting and filing 12 tines to 20cm in length. I then used two pieces of acrylic offcuts from my other laser cut creations to sandwich the tines and produce a note. 3mm bolts between every tine make sure that each is fastened down – but these have to be tight, so 3mm acrylic is used on the other side of the plywood, under the head of the screws so that the plywood is not compressed.

Once I had the bridge in place I tuned the kalimba and realised that I had to secure the ends of the tines with another piece of acrylic offcut to reduce the buzzing sound. Now the tonal quality is pure and mellow (I just wish I could play something on it).

The prototyping process is not quite over (there are some electronics and some software to come), but I already have a list of design improvements:

• Smaller, thinner, and tines closer together
• Etching on bridge and incorporated around sound hole rather than under tines
• Revise box design and not use miniature screws
• Hide ends of tines (like a baffle)
• Improve upon the screws in the bridge – use a allen\hex head, or similar, for easier tuning
• Raise the tines near the sound hole for easier plucking

To show you how a kalimba (and similar instruments) should look and sound, following are a few videos:

This entry was posted on Monday, August 11th, 2008 at 7:45 pm and is filed under Laser Cutting, SketchUp. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.