Introduction: Clothespin Piano for IPad

About: Background in Electrical Engineering, Computer Science, Robotics, and Tangible Interfaces from MIT. Other projects I've worked on can be found at

Touchscreens are great, but when it comes to playing music on them, the lack of physical keys can be a drag. So I decided to round up some household stuff and make a piano keyboard that tricks the iPad into thinking it's being played by your fingers (with the help of some clothespins and aluminum foil)!

It's quite easy to make a capacitive piano interface, and all told it cost me less than $5. All you need is some wooden clothespins, foil, markers, tape, rubber bands, stiff cardboard, and some patience to cut and piece it all together.

Step 1: Gather the Materials

For this project you'll need:

  1. Clothespins (1 for each key you want to make)
  2. Rubber bands (10-20)
  3. Aluminum foil
  4. Pens, pencils, or thin markers to prop up the keys
  5. Tape (any kind is fine)
  6. Stiff cardboard or card stock for the base (I repurposed a sturdy folder)
  7. Some basic cutting tools (scissors and something to make small holes)
  8. Straight edge or ruler for drawing lines

Step 2: Measure Twice, Cut Once

Place your iPad on the stiff cardboard material and cut it down to size, leaving a section big enough to build the piano keyboard on.

Carefully cut the cardboard!

Then, make marks for the edge of each key as it appears on the app you want to use (I'm using Fiddlewax Pro because it has a 15-key section at the bottom). Do this on both edges of the cardboard, then connect the marks to make straight lines for each key edge.

Lay the iPad on top of the cardboard and draw a reference line along the bottom.

Step 3: Separate Clothespins and Poke Holes

Now get your bag of clothespins and separate the wood from the metal spring of each one. This can be done with a simple twisting motion (just be careful not to pinch yourself!).

Once you have the clothespins separated, line up two halves tip-over-tip as shown in the image above. Also note that the far end over the touchscreen nicely aligns with the area you want the key to press.

Make two marks, corresponding to the notch in each clothespin half (where the end of the spring was). Draw a line across the entire keyboard where those notches were, as a reference for the other keys.

On the notch line and in the center of each key, make a mark for the rubber band holes.

Poke a hole through each of the center marks. If your cardboard is soft, you can use a pencil or screwdriver. If it's too stiff, you may need to use a drill bit (just be careful!). The size of the hole isn't too important; just make it large enough to fit a rubber band.

Step 4: Add the Rubber Bands

Grab your rubber bands!

Squeeze one rubber band through the first hole and leave a loop large enough to fit a clothespin. Then, continue poking the same rubber band through neighboring holes until it gets snug. For my key spacing and rubber bands, I was able to get 3 keys per rubber band.

If your rubber band it a little too loose for the number of holes you have, just tie a knot in it on the other side of the cardboard.

Play around with the tension, as this will determine how hard the keys need to be pressed.

Once you finish the placing clothespins in the top row, repeat the same for the bottom row.

Step 5: Line Up the Keys

Place pencils or markers under the round part of the clothespins to prop them up.

Hooray! Now you have lots of clothespins, all held to the base cardboard with rubber bands.

But without anything to guide them, they slide off of each other and fall over. Don't worry, just grab some more cardboard and make some spacers -- voilà!

Of course, all those little cardboard pieces will get knocked out as you play, so we'll place a rubber band around them to hold them down.

To keep from pushing the spacers sideways, I also made a triangular block to brace each side. Then I put a rubber band over the whole thing.

Give it a try and make sure all the keys work.

Step 6: Prepare the Foil

To make the capacitive touchscreen react like your finger is touching it, we need to use something conductive. Aluminum foil will do the trick nicely.

First, tear off a little rectangle of foil and roll it into a tiny stick. Then coil it around itself, until you have a disc -- this will be the pad that represents your fingertip.

Next, get a larger rectangle and fold over the sides to make it a bit thicker.

Grab a spare clothespin half (this will help you shape the foil "fingertips"), then place the little foil pad on it, as shown. Take the larger rectangle and wrap it around, encasing the foil fingertip pad.

Being careful not to tear the foil, fold it back over the top and make it into a flat wire that sticks up.

Step 7: Mount the Foil Fingertips

Remove the foil fingertip from the spare clothespin and add it to your piano assembly:

Slowly place it over the clothespin as shown. Then tape it down to hold the foil in place (but be careful not to tape over the fingertip!).

Repeat for all keys. This takes a little while.... Be patient and put on some good music while you work. :)

Step 8: Connect It All Together

Now all of the foil fingertips need to be connected together. To do that, make a long foil rod, then carefully wrap each foil fingertip wire around the rod.

Finally, we need to get the foil to touch either you (i.e. you could just hold onto it, but that's annoying), or the casing of the device itself.

So make another foil rectangle and place one end on the base cardboard, under the iPad. Then twist the other end and connect it to the foil rod that joins all the keys.

That's it! The main parts of the piano are in place. Now take a few minutes to dial it in and make sure all connections are secure.

Step 9: Make Music With Your New Piano!

Place the iPad back on the cardboard base and line everything up. You may need to press each key down firmly the first time, to get the foil pads to match the angle of the screen.

Now load up your favorite music app and start playing!