I made a guitar that plays itself.
It has nothing to do with this competition, but I felt I should share it on here because it deserves some recognition from an audience who can actually appreciate it.
Here it is playing the only song it knows how to play: Mr. Jones by Counting Crows.
Because I'm sure you're curious, I'll explain the important bit - how the chords are formed:
To make a chord, fingers have to be pressed on the frets in a particular order. For example:
C = 0 3 2 0 1 0
G = 3 2 0 0 0 3
F = 1 0 3 3 2 1
Am = 0 0 2 2 1 0
Because fingers are dextrous, a human can play all of these (with practice).
To get the robot to do them, I've got three coordinated axles running across the first three frets.
Each axle has four more axles - let's call them N S W and E.
Each axle handles only its own fret, and knows it's in sync with the other two.
All the "North" axles coordinate to play a C chord.
All the "South" axles coordinate to play a G chord.
You get the idea.
So this:
C = 0 3 2 0 1 0
G = 3 2 0 0 0 3
now becomes this:
Axle 1 N: 0 0 0 0 1 0
Axle 2 N: 0 0 1 0 0 0
Axle 3 N: 0 1 0 0 0 0
Axle 1 S: 0 0 0 0 0 0
Axle 2 S: 0 1 0 0 0 0
Axle 3 S: 1 0 0 0 0 1
Then you have to reshuffle to group the axles. And - here's the hard part - build them in such a way that the "fingers" don't bump into each other while spinning around.
It's not perfect by far, but still, I'm pretty pleased with it!