SCOTTYCHORD

Battery-powered mini piano. Play a song on a virtual piano and see

it performed on the Scottychord real-time.

The goal of our project was to build a physical piano-like instrument that could play a

song inputted by a user. In order to play the piano, the user presses keys (on laptop) in

order to play notes on a virtual piano UI. The Scottychord then plays the song back with

the same melody and rhythm that was played. The instrument is built with lyre strings

hit by small wooden hammers. These hammers are glued to motors which spin and hit the

strings to make music. Each motor is connected to a relay, and each relay is connected to

a single 9V battery source. The relay trigger is connected to an Arduino MEGA’s digital

output pins. The piano interface is built using pygame and serial. It sends the song to the

Arduino MEGA as a string. MEGA receives the string via USB and runs code that parses

the string and plays the song.

We ended up changing much of our implementation. Previously, we designed and 3Dprinted a mechanism to pluck the lyre strings, taking inspiration from guitar picking and

a harpsichord (the precursor to the modern piano). However, we found out that the

mechanism was too heavy and required too much precision for the motors. We pivoted to a

wooden hammer mechanism to directly hit the strings to produce sound. The relays ended

up being used to control which keys are played and when. The strings were strung across

the top of the instrument similar to a lyre. We used hot glue to hold the wood together

and a small breadboard to share the battery source.