The Musical Handrail is plays a set of mp3 files as someone's hand touches the railing at each step. The set of mp3s can easily be switched out from playing musical piano notes to drum beats or anything other sound effects you may want to drop in.
This project was made to demo a new SparkFun product called the Mux Shield from Mayhew Labs. The Mux Shield expands an Arduino to have 24 IO pins so that one microcontroller can easily control many things. 

A while back I saw a musical staircase use for a guerrilla marketing campaign for VW and wondered if I could recreate the musical staircase in less than 24 hours for under $200.

The one thing I wanted to change is the option to not trigger any sounds, so instead of using pressure sensors or lasers on the steps, I thought it would be a good idea to put it in the handrail and detect the changes in light as someone's hand passes over the railing. 

I also though this would be more fun since one person could easily trigger multiple nearby sounds by drumming or covering various parts of the railing. 

Since SparkFun is all about open source hardware and software the Arduino and Processing Code is below. 

The entire thing came together pretty smoothly and I recorded the process to show to SparkFun customers one of the many things they could use the Mux Shield for. 

The Mux Shield quickly sold out and continues to sell out regularly even a year after it was introduced. 

Processing
Arduino
Light Sensors
Mux Shield

Software - Chris Rojas
Hardware - Chris Rojas
Hardware - Mayhew Labs