Creating a footstep piano

Question

I have this idea for a project I'm working on but I'm not sure where to start.

The ideia is quite simple: there will be platforms on the ground, and when people step on them a musical note is played. Each platform produces a single note.

I was thinking about using a piezoelectric sensor along with a digital keyboard, but I'm not sure if this is the right path or if there's an easier way to do it.

Answer 1

For the sensing, you could use capacitive sensing, light sensing (e.g. block an IR beam or an LDR installed under the floor) or pressure pads (various types available or make your own with Al Foil)

So for example, you can do this easily with a small microcontroller with a cap sensing peripheral. A PIC16F1519 is an example with 28 cap sense channels (if you need more then there are other larger options) and only costs $1.37 in volume (so proabably ~$1.80 for 1)

You would install sheets of copper/aluminium foil under the keys, and attach to each channel. Tuning the setup probably wouldn't be too hard as you will likely get large changes compared to finger sized solutions.
For the pressure pad version, you can use something like these 1.75" x 1.5" resistive pads and attach directly to an input pin with largish pullup (or use a comparator):

Then you can either use the micro itself to generate the tones (e.g. Filtered PWM) or send a MIDI code for each key to something else (e.g. synthesizer, PC, etc) to play them.

Answer 2

Easiest approach would be to use the MIDI protocol, which is a very simple serial protocol that just about every microcontroller supports through UART and many keyboards and computer programs can understand. You can build your own, or use some of the many resources for hobbyists and hackers, like those found here.

For a sensor, this seems like a perfect application for a Sensitronics Force Sensitive Resistor! Extremely easy to use, and have good range for uses like this. You could do it cheaper, but I don't think you can do it easier. Piezo electric would work, but you'd need to build a charge amplifier for it, so it's a bit trickier.