Cheap Expandable Floor Piano

None I created design to build a big and expandable floor piano (1 to 8 or more octaves) with learning mode (led will light the keys), driven by phone (first with midi file and great sound banks only). The project must be cheap (I'm doing it for free, but it will be used in a music school and I'd like to have it used in more than one), strong (we will have hundreds of kids that will play on it, it can't be made of materials that will not last in time), and expandable (size and price matter, 3 octave makes it more than 3 meters long and around 1000$). I'd like to be able to keep price under 250$ each octaves using open source and as cheap as possible hardware.

I already have 2 different release, and am working on the third one, with fully redesigned board.

Side story They were plenty of challenges with this piano.

I had a lot of trouble but got all bullet ticked:

- Cheap (using micro-controllers for the piano)
- Big but could fit in a car (from 1 to 8 meters long)
- Expandable (from 1 to 8 octaves now)
- Strong (it's for kids, even if adults love to play too)
- No moving parts (same reason as above)
- Easy to use alone
- Added a Raspi to use the piano as a Midi controller, and added a accompaniment mode and a learning mode.

I started to think about this project after having seen the movie Big (with Tom Hanks). I started small building one onote and trying a zillion things to detect contact between a translucent sheet of plastic (contactor, spring, sheet of reactive to pressure plastic, ..), I finally found the solution using capacitive detection will be the best for the constraints I have to take into account. Finding the Silver Fabric trick took quite long, there are plenty of other solutions there, spray, electrolysis,... but Fabric is cheaper while being the simplest to implement.

The Piano is used now in the music school especially to work on rhythm, Biggest play has been on 7 octaves, with 4 kids playing, but it has not been recorded...

At this day, I built 8 octaves, 4 are mine and are in my music room, and 4 are used in the music school.

Frequently Asked Questions
What inspired you to do this?
The movie Big with Tom hanks inspired me in 93. Since then I wanted to make one, but I gave myself a lot of constraints that were not easily solved before microcontrolers become so popular.
How long did it take to make it?
20 year to think about technical solutions for the constraints I placed to the project. 2 years when I really started.
How long have you been doing things like this?
For as long as I can remember. I started to fix Radio and TV when I was 10, and never stop to try to make things better, and to bring electronics and software to my various passions.
How much did this cost to do?
Have you done other things like this?
I made plenty of small tools, tuner, pianos.
What did you wish you knew before you started this?
Are there plans available to make this? Do you sell this?
The full construction detail is explained in
What’s next?
This project will evolve a bit more, but nothing big now.

Frederic Tachet : Maker, Senior director of software dev
The maker Frederic Tachet
Software dev since 78, electronics since 1980, started DIY kind of stuff since then. As musician, I wanted to create a big piano to offer it to a music school, so I made it and present it today. I'm working on laser harp now.

Connect with Frederic Tachet
How I can help you:
let me know, I can basically work on any subject
How you can help me:
You can visit to get more information, and you can add yourself to the team on hackaday if you want to participate to next version.

Picture of the builds :
The whole build, and explanations :