In November 2014, we displayed our first completed project as a club, the Staircase Piano. The idea for the project was given to us by Professor Barry Brown before the club was even formed. Throughout the semester we worked towards putting the piano together for a final presentation before the end of the Fall 2014 semester.
We started out the project only using an Arduino for both the sensor readout and the sound creation. We were creating sounds using pulse width modulation on the Arduino and outputting that signal to a 3.5 mm stereo jack.
The sound coming out of the Arduino wasn’t producing quality sound so we looked into other options. We learned that creating the sounds on the fly wasn’t the best idea so we turned to using digital sound files and playing them with a Raspberry Pi. This drastically improved the quality of the sound and it allows us to expand the project in the future.
The sound is triggered using a optical switch. The switch works by aiming a laser at a photo resistor and reading out the value of the photo resistor. A photo resistor works by using the photo electric effect. When light photons hit the surface of a photo resistor, they push the electrons off of the semi-conductive plates on the surface which creates a current. This current can be measured by the Arduino to get an accurate readout of the light level on the photo resistor.
For More Detail: Staircase Meets Piano