where particular notes can be found. Being a MIDI
instrument, a small software change allows you to
tune the lyre however you want, and I will indicate
how to do this later. For now, I’ll describe the default
The MIDI lyre is a diatonic instrument. It’s tuned
according to a C Major scale with no sharps or flats,
i.e., the white notes on the piano keyboard. Diatonic
tuning is very common for both lyres and harps
and is particularly common for folk instruments.
Diatonic instruments are easy to play because it’s
impossible to play a “wrong” note that is not in
whatever scale they are tuned to. The tuning of
the 12 strings of the MIDI lyre is shown in Table
String 0 is G and therefore a C Major scale
starts on string number 4 as shown in Table 2.
For any musical theorists, this puts the MIDI lyre
in Mixolydian mode (like the mountain dulcimer)
because although it is tuned to a C Major scale,
the strings actually start at G.
You get a mode by playing a C Major scale beginning
on different white notes as shown in Table 3. The normal
C major scale happens to be Ionian mode.
Now let’s mark some notes. Take some red insulating
or masking tape and wrap it around the top and bottom
of strings 3 and 10. This marks the C notes. Next, take
some blue tape and wrap it around the
top and bottom of string 6. This marks
This is a standard way of marking
the strings of a harp or lyre because it
tells you where you can find lots of
1. The red strings are the tonic, C.
2. The string before the blue string
is the third, E.
3. The blue string is the fourth, F.
4. The string after the blue string is
the fifth, G.
You can see that the thirds and
fifths are either side of the blue string;
this makes it very easy to find the C
Major chord, CEGC.
Now that you have “strung” the
lyre, you can connect the strings to the
Connect each string to the
appropriate pin of the MPR121 using
30 cm male-to-male Dupont jumper
wires. These usually come in ribbons of
40, and the best way is to break off two
ribbons with six wires in each.
One end of the wire is fastened in the terminal block
and the other end plugs into the breadboard at the
appropriate MPR121 pin. The MPR121 breakout board
has 13 pins down one side. The first pin is GND (don’t
connect this to anything); then we have pins labelled 0 to
11 that are the touch sensor electrodes. Connect string 0
to pin 0 and so on.
Everything should now be
connected correctly. A completed MIDI
lyre with electronics and strings is
shown in Figure 7. Check your wiring
again, and then you can program the
If you haven’t used an Arduino
before, I suggest you go to the Arduino
home page at https://www.arduino.cc
and do a little reading. In particular,
take a look at “Resources/Getting
Started” for instructions on how you
program the boards.
Arduino boards are best
programmed using the new online web
editor. Connect the Uno to your
computer via USB and go to the
Arduino Home at
“Arduino Web Editor.” The web editor
should open and automatically detect
your board. If not, select it from the
drop-down menu. Go to Examples/Built
in/01 Basics and load and run Blink.
July/August 2018 31
■ FIGURE 7. The completed
MIDI Lyre Default Tuning
Note GABCDE FGABCD
Color Red Blue Red
C Major starting on… Mode Scale
C Ionian CDEFGABC
D Dorian DEFGABCD
E Phrygian E F G A B C D E
F Lydian FGABCDEF
G Mixolydian G A B C D E F G (the MIDI lyre)
A Aeolian ABCDEFGA
B Locrian BCDEFGAB