Floor Piano




Introduction: Floor Piano

About: I'm a Software Developer with a background in education. I love art, museums, art museums, and building stuff.

I made this floor piano as a project for work. We were inspired, of course, by the movie BIG - you know the scene - where Tom Hanks and Robert Loggia play on a giant floor piano at FAO Schwarz.

It gave me a great deal of trouble, and took a very, very long time. I had no idea what I was doing in the beginning, but slowly, borrowing ideas from smart people online, it finally came together. It's got 11 keys (the black keys are just for show), and uses a Makey Makey, Scratch, and pressure plates to complete the circuit and activate the sound. Hopefully, my instructable will be thorough (and clear) enough that you can make one too!

Step 1: Stuff You'll Need

For this project, you will need the following:


Makey Makey - If you don't know what a Makey Makey is, here's their website: https://www.makeymakey.com

Account for Scratch: https://scratch.mit.edu - totally free and easy!

Whole lotta cardboard for your keys (22 pieces, cut to 10" x 40" rectangles - preferably with no folds in them - also, if you use the same thickness of cardboard throughout, it may save you some headache later)

Roll of aluminum tape (you will probably use two of these)

Large sheet of thick foam (I used something like this, which we happened to have on hand, but you could also use foam exercise mats, which might be easier all around) - you're going to cut this into 22 strips, 40" long x 1 1/2" wide

Glue gun and glue sticks

Wires of two different colors - I used black and red

Wire cutter and stripper

Soldering iron and solder

Duct tape (and a lot of it)

White blackout cloth (you'll need about 3 1/2 - 4 yards)

Sewing machine

Black acrylic paint (plus whatever colors you desire)

Adhesive Velcro strips

Step 2: The Keymaker: Part One - Adding the Aluminum (or Aluminium, If You Live Across the Pond)

Each key of your piano will use two pieces of cardboard. You're going to put them together like a sandwich, with a small space in between the top and bottom sandwich layers. The first picture is a front view of one key, sitting on a table - notice the small gap between the layers.

To prep your keys, first off, you need to put a layer of aluminum tape on the inside of each key piece, leaving a narrow strip uncovered on either side (this is where you'll glue down your foam strips).

*You'll notice in the picture above that one of my key pieces is shorter than the other - this is because I had a hard time finding single pieces of cardboard that were long enough. I finally settled for some shorter pieces, and oriented the keys so that the shorter ends would be at the tops of the keys. (I imagined that kids stepping on the piano would be more likely to step on the bottoms of the keys.) I also decided to save myself some aluminum tape and kept the aluminum layer on the opposite key piece (the longer one) short as well. Once I put the keys together, I filled in that extra space with leftover pieces of foam. If you're able to find enough cardboard that is long enough, then you don't have to worry about this. Ideally, both pieces of your key will be 40" long, and the aluminum layer will extend all the way from the top edge to the bottom edge. I also decided to add a little extra aluminum tape to the fronts of my keys, wrapping it around that edge. (This is why you see aluminum on the fronts of my keys in the first picture).

*You might also be able to use aluminum foil rather than aluminum tape (and maybe save a bit of $), but we anticipated that our piano might get some heavy use, and opted for more durable materials. Aluminum tape is a whole lot thicker than aluminum foil. Also, the adhesive on the aluminum tape made the process very easy.

*My vocabulary is limited, so I use the terms top and bottom a lot. Each key is made like a sandwich, so sometimes I'm referring to the top sandwich piece or the bottom sandwich piece. Also, as you're constructing the piano, you want to decide beforehand which key edges are which in reference to the orientation of your piano. Which edge of the key will be the top, and which the bottom. If I'm still confusing you, you can check out my drawings.

Step 3: The Keymaker: Part Two - Gluing Down the Foam

Now it's time to glue down the foam strips on either side of the bottom sandwich portion only of your key. In my first attempt, I used Elmer's glue, and though it worked, it didn't take a whole lot of effort to loosen the strips (they came up if I tugged gently), so I switched to a good ol' reliable glue gun. Each strip of foam is 40" long (the same length as the key) and about 1 1/4" to 1 1/2" wide. The type of foam I used cut quite easily with a regular (but sharp) pair of scissors. To mark your foam, you'll want to use a marker (a pencil or pen will tear it).

Step 4: The Keymaker: Part Three - Attaching the Wires

Before you tape your piano key sandwich together, you need to attach the wires. Each key has two wires attached - a ground wire for the bottom sandwich piece (I used red for my ground wires), and another wire (I used black) for the top sandwich piece. (I'm sure this wire has a special name too, but I'm not an electrician, so I don't know what it is).

You'll want to strip the insulation off the ends of your wires so that you can tape the exposed wires down directly onto the aluminum layers of your key (the conductive layers must be touching). I stripped about an inch of insulator off of each end.

Use pieces of aluminum tape to tape the exposed end of the red wire (the ground wire) to the bottom (sandwich) half of your key, at the top edge of the piano, and to tape the exposed end of the black wire to the top (sandwich) half of your key, also at the top edge of the piano.

All of these wires will connect to the Makey Makey, at the top center of your piano, so make sure that your wires are long enough (with some extra) to reach. We'll attach the opposite ends of the wires to the Makey Makey in the next step.

Step 5: Makey Makey

Now it's time to hook everything up to the Makey Makey.

The ends of all of your wires should now be taped down to their respective spots on the insides of your keys.

Now you need to strip all of the other ends of those wires. This time, we'll be soldering them down to the Makey Makey, and we don't want the ends of any of our wires to touch one another - so be conservative. Only strip a small bit off of these wires to leave only about a quarter or a half centimeter exposed.

The red wires are easy - they're all going to be soldered down onto the silver strip at the bottom of the Makey Makey labeled "EARTH." These are your grounding wires.

If you've labeled your keys from the left to the ride of your piano "key 1, key 2, key 3, etc." as I did, then this is how you will hook up your (black) wires to the Makey Makey:

Key 1: left arrow

Key 2: up arrow

Key 3: right arrow

Key 4: down arrow

Key 5: space

Key 6: w

Key 7: a

Key 8: s

Key 9: d

Key 10: f

Key 11: g

*Notice in my picture that only the arrow and space keys are on the front of the Makey Makey - the last 6 keys (w, a, s, d, f, and g) are on the back of the Makey Makey, and you have to use the wire pins that come with the Makey Makey kit to attach to these spaces. I soldered the exposed end of my black wire to one of the exposed wires on the pin (and then covered the solder with electrical tape) and then pushed the opposite end of the pin into the corresponding key I wanted.

The Makey Makey, once it's plugged into your laptop, will bypass the keys of your keyboard. You'll complete the Makey Makey circuit for each key by stepping on your key (sandwich) and pressing those layers of conductive aluminum together. These pressure plates, when pressed, will activate the sound - just the same as if you'd pressed a key on your keyboard.

Step 6: Programming in Scratch

Okay, now comes the fun part...

If you don't already have an account for Scratch - make one!

The reason I used Scratch is that it's already got a good range of piano notes in its audio database. All I had to do was assign each note a corresponding key on my laptop's keyboard, and I was good to go!

To set up a quick program for your floor piano in Scratch, first click on "Create" from the menu at the top of your screen. The gray program writing block on the right side of your screen should show three tabs at the top: scripts, costumes, and sounds. Select the "Scripts" tab if it isn't already selected for you. Now click on "Events" next to the sienna (or brown) bar underneath.

Drag and drop the "when space key pressed" event onto the program writing block. When you click on the small down arrow next to the word "space" a menu drops down, allowing you to choose from a set of keys on the keyboard. Choose "left arrow."

Now click on the "Sound" option next to the magenta bar under the Scripts tab. Drag and drop "play note __ for __ beats" so that it fits directly underneath the "when left arrow key pressed" command (they'll snap together automatically). Select note "55" from the drop down menu. Congratulations! You've just completed one piece of code!

*Notice that with Scratch, you can program the amount of time you want the note to play. You can play around with this to get it to where it suits you. I have mine set for 0.5 beats.

Now on to the rest: Here are the keys you want, with their corresponding notes (and a screenshot so you can see what it will look like when finished):

Left arrow: note 55

Up arrow: note 57

Right arrow: note 59

Down arrow: note 60

Space key: note 62

W key: note 64

A key: note 65

S key: note 67

D key: note 69

F key: note 71

G key: note 72

*Notice that all of the note numbers aren't sequential - that's because we're skipping the black notes on the piano.

*Also, this is just once particular section of a full piano (obviously). I'm not a piano player, but I knew (with my keys limited) that I wanted a good range on my giant (mini?) piano that included middle C. I can play the Itsy Bitsy Spider, or Old MacDonald Had a Farm with this range - you may want to choose a different range for your piano.

*Mess around with the programming just for fun! With Scratch, you can change the sounds of your keys at random, and replace them with some crazy things - bubbles popping or a cat's meow! That's something they couldn't do with the floor piano on BIG!

Step 7: The Cover-Up

By now, you should have a working piano that looks something like the first photo. Notice that we also found a set of small speakers that we hooked up to the computer to amplify our sound. Though this piano is already pretty darn awesome as it is, you may choose to present something a bit more appealing than a pile of cardboard, duct tape and wires.

Unfortunately, I didn't document this part of the process as well as the others, but hopefully I can explain myself well enough.

To finish my piano, I bought about 4 yards of white blackout cloth (you can find this at some Walmart stores). I bought it from a large roll that was 54" wide. Basically, I cut the fabric in half, creating two equally sized pieces, and sewed what amounts to a giant pillowcase to tuck my keys into. I then added a line of stitching between each key to create a sort of pocket to hold the keys in place and prevent them from sliding around (this stitching does not extend the full length of each key - it runs about 30" long, stopping about 5" from the tops and bottoms of each key. I'll lay out the steps in more detail shortly, but first...

A word about measuring -

We knew that we needed to be able to fold up the piano (accordion-style) to store it when not in use, so my keys are spaced a little bit wider to allow for this fold. To determine the final length that I needed for my cloth, I first sewed the bottom edge of my pillowcase (which runs along the bottom edge of the piano) and one side to create one corner. I tucked a key into that corner, and then, smoothing the fabric, pinched the opposite side closed. I then measured the distance between the edge and where I pinched the cloth to determine about how wide I needed the fabric to be to allow enough space for my keys. For most of my keys, this came out to be 11" wide. However, I had three keys made of a thicker cardboard, and so the pockets for these keys are about a half inch longer than the others. So you see, I'd love to give you exact measurements that you can use, but it really depends on how thick the cardboard is that you've used. To allow for the accordion folds, I added a small amount between each of the keys that is equal to the height of the key sandwich.

Sewing -

First, you need to sew your piano "pillowcase." The 54" width of the blackout cloth was perfect - it was just the right amount to cover both sides of my keys, and leave a little extra at the top to hide my wiring and Makey Makey. I cut the 4 yards in half, making two 2-yard pieces, both 54" in width. I sewed two selvage edges together to make the bottom edge of my piano.

*Remember when sewing that you place the right sides together (or the sides of the fabric that you want facing out when finished - you're going to sew the seams and then turn your pillowcase right-side out).

Now stitch one side together. It doesn't matter which side you choose, but you'll need to complete this step so that you can measure how long you need your fabric to be (see my note on measuring above).

Once you've determined your final length, you can measure it out, mark it, and then sew the opposite side edge, trimming the extra fabric. Congratulations, you've just sewn a gigantic pillowcase.

*Before turning your pillowcase right-side out, use duct tape to tape down those inside seams. (If you don't, it'll be hard to insert your piano keys because they'll catch on that extra fabric. By taping them down, it'll help make the process nice and smooth.)

The second step, now that you've got your pillowcase turned right-side out, is to add the stitching to create the key pockets. I've included a little drawing to help you (ignore the fact that my drawing has only 8 keys - I ran out of paper).

Notice that I have two stitches between my keys - that's because I added a little extra for that accordion fold. If you're not worried about folding up your piano, then you don't need to add that (but be sure to account for whatever you choose in your measuring). Notice also that the stitches are only about 30" long - they don't go to the bottom edge - if they did, you would have a hard time fitting the bottom of your key snuggly into the pocket.

Step 8: A Paint Job

I used acrylic paint for my piano - once it dries, it won't dissolve with water, or smudge. You can use painter's tape to mark off your lines, but I used simple masking tape, and it seemed to work pretty well. The black keys that I painted on are about 20" long (half the length of the white keys). I painted the spaces between the keys black to emphasize their separation, and also to cover up my not-so-neat stitches. You may want to have a bit of white acrylic paint on hand in case you need to do a few touch-ups (I had a few myself).

I also used adhesive Velcro strips at the top of each key to hold the top part closed when in use, but they also allow me to access the wiring and keys inside in case of any needed repairs.

Step 9: And Now It's Time to Play!

In this video you can hear that I replaced a note for one of the keys with a cat's meow!

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    8 Discussions


    Question 1 year ago

    I have created the keys and placed the wires on them. I have the makey makey but need help with the how it is attached. Can you please email me at dray@hancockschools.net?


    1 year ago

    Hi! I'm not real familiar with that material, but I think that as long as it is springy and bounces back to it's original shape after being stepped on time after time then it should work well. Foam mats are another option (like the foam mat tiles you might see in a kids' play area). If the insulated boards bounce back they may be a good option if they're more durable than the mattress foam that I used.


    2 years ago

    I really like the clever sandwich design for the keys. I am a bit worried about dents shorting the keys.

    You could save a bit of money by using an STM32F103C8 black pill board ($2) and a quick Arduino sketch instead of the Makey-Makey. Just connect the keys to digital pins, use the addMidiHID branch of the Arduino core for the STM32F1 to send keyboard events, and you can use the same Scratch code on the PC. (Or you could even make a MIDI keyboard that way.)


    2 years ago

    Very cool!

    I saw one once where they used aluminum window screen seperated by 1/4 inch foam with holes cut in it. Holes were about 1/2 inch in diameter, but there were a lot of them. You could step almost anywhere on it and it would work.

    Keep Building!


    2 years ago

    Hi. I love this! We made a similar thing for a children's museum many moons ago. In our case, we ran the contacts to a MIDI footswitch controller, so we could turn each key press into a note on / note off signal to a synthesizer. I was thinking about this recently, as I am working on an Arduino project that does something similar - turns switch closures into MIDI note data. Maybe I'll Instructablize it when I'm done. Would make a nice companion project.


    2 years ago

    Love the idea!
    But how durable is the cardboard? Any ideas for a lightweight alternative?

    DIY Hacks and How Tos

    That looks really fun. I am seriously thinking about making one of these for my local children's museum.


    Reply 2 years ago

    You totally should! I work at a science center where we get tons of children visitors - but I have yet to test it on a busy day with lots of little feet. We're still working out exactly how to do crowd control, but I'm sure the kids are going to go nuts with it.