7

LENS

parts of the guitar. In hindsight, mounting
everything on the top surface would have
made a lot more sense. Another decision
I would change in
retrospect would
be the circuitry for
the neck, which I
squeezed inside the
neck itself, making the
fretboard wide and
hard to play. Giving the
guitar a bigger body in
the first place would have made more room
for circuitry and allowed me to have a less
chunky neck.
One of the final parts of the build was
to decide the function of each knob. I
squeezed as many potentiometers onto the
body as possible, knowing I would want
control over a wide range of parameters in
the Teensy audio code. After many happy
hours experimenting, I settled on a layout
where the more frequently adjusted (i.e.
coolest) controls were within closest reach.
It’s nice to know that changing the layout in

future will require only a few lines of code

and some new labels.

CONCLUSIONS

I have become too attached to my guitar

to think of it as a prototype, yet I suspect

it is; it contains both too many flaws and

too much potential for there not to be

another iteration. I was proud to be able

to show off my guitar at Maker Faire UK

this year (and prouder still that it survived

a full weekend of testing by enthusiastic

children), but I learnt a lot about what I

would change next time.

While the sounds the guitar generates

are unique and interesting, the playing

style is definitely unintuitive. I had hoped

that any guitarist would be able to pick up

Bjarkardóttir and play it unthinkingly, but

Maker Faire disproved that. That said, there

is nothing stopping me from refining the

design, perhaps using something closer to

an existing guitar neck, and I would like to

have another go at making the right-hand

strings touch-sensitive. I would also like to

add a battery, possibly even a speaker, and

expand the range of sounds available, all of

which should be relatively simple.

Overall though,

I’m just happy to

have made a guitar

that – despite its

flaws – looks and

sounds unique, and

won’t break halfway

through a gig. I hope

that this project will

inspire people to have a go at making their

own instrument, because the technology

available today makes it easier and more

rewarding than ever to do so.

Adding unlimited inputs

Anyone who has attempted an ambitious microcontroller project is likely to have run out of analogue

inputs at some point. Even with the Teensy’s huge number of pins, I needed a way to read more

potentiometers. The solution was to use several 4051 multiplexer chips, which each take eight analogue

inputs and allow you to read them one by one. The process of switching between the chips’ inputs is so

quick that you can add an almost unlimited number of them to a project.

Above

All good projects start with a diagram

Right

The guitar is played with a conductive plectrum

Far Right

Are you ready to rock?

While the sounds the guitar generates

are unique and interesting, the playing

style is definitely unintuitive