I wanted to make some type of an input system (or a keyboard). During the semester, I was introduced to modling and casting methods and gained knowledge on using casting rubbers (silicone) from Smooth-on, which is the company that sells mixing liquids. I was especially interested in clear silicone. To me, it appeared more visually pleasing and interesting (BTW, I learned about clear silicone from TMG during the semester).

I could not be sure what kind of keyboard I wanted to make yet and so I decided to do some testing. Below are images of my very first trial with the material.

For basic functionality of any kind of a keyboard, I decided to make my own pressure sensor because it was the simplest way to detect a press and because commercial ones were too expensive (and I needed a lot of them). It was double the good because I got to save tens of dollars and had so much more fun making it.

My first try was a complete failture. I used conductive foams (black cylindars) to measure the difference in resistance when pressend down versus when released. It turns out that although conductive foams are called 'conductive' they were not really conducting electricity. Also my silicone turned too thick to detect gentle press of hand.

I decided to design a piano keyvboard because it would be more interesting to hear back some msical sounds than typing and seeing letters on the computer screen. I wanted to make a circular keyboard but decided to start with one quarter of it and test it. If I liked the design itself (just as a quarter of a circle) then I would keep it.

Once I had the silicone layers ready, I quickly made top and bottom piece of copper sheets that will act as two conductive plates between a resistive material in pressure sensors. Silicone was a great insulator!

Below is a video of my very initial attempt with the silicone keyboard with copper sheet sensors. One problem I noticed was that the middle silicone piece (one with lots of holes) was too thick and did not stretch enough for the top copper plate to be able to reach down. I decided to deal with it later though.

Now it was time to program! I used my Fabduino that I made from past class assignment.

Important things to remember (and the things on which I often made mistakes):
* Hold down the Reset pin when Booloading the Programmer
* Make sure to select correct Programmer, Connection and Board
* Double check if input pins are correctly connected

I first tested every keyboard on a large breadboard. Once I was certain that the input pins were reading the right voltage from each keyboard, I decided to solder the board into a smaller one using smaller resistor size and really make it compact so that later it could fit into the structure design I had in mind.

My piano keyvoard was to rest on top of some cylindrical shape. Here in the images below, I laser cut out pieces in growing size as the layers reach towards the bottom. I needed some space to put in all the boards and programmers. I think the space I have is ideal.

There are two detachable pieces to the structure design. Top piece has the silicone keyboard only and the bottom piece contains all the chips and boards, including all the connection required for power supply. Speaker also is internally connected and only sticks out from a small hole I made in the model.

Below is a video of my Silicone Keyboard! :)

For the second to the top most piece in the structure, did not enlose the ring but left ~10cm opening so that I could have the wires come out. One below the bottom piece where the silicone keyboard rests also had an opening with similar length for the wires to bo back into the structure to hide.

Here in the images below shows all the wires I used. Heat shrink rubbers were very convenient and useful although I forgot to put them on for the first three pieces. But because the wires were stiff enough to stay still in position, I did not need to worry about it too much.

Part 2: Redesign the Mold

In order for my copper plates on top and bottom to touch each other, I needed some kind of a hold that would open the connection point. Therefore, I designed and cut out circles from the thin layer of silicone and made mulfiple holes. It also is a result of design decisions.

I glue-gun down the molding pieces. Green cylindars on the right image above shows where the holes would be made. I mixed the Solaris solution in 1:1 ratio, slowly poured the mixture into the modling piece and then baked it in oven for 15 minutes at temperature 150F.

FINAL PROJECT: SILICONE KEYBOARD

Part1: Laser Cut Molds & Test Silicone

Part 3: Circuits, Connections, Soldering

Part 4: Structure