Introduction: Make a Pedal for Rotating the Linux Cube

Recently I posted an instructable about a footswitch to hide all the windows in Windows XP, but I spend most of the time in Linux programming drupal websites, so I made this one to be used "At work also" =P

The other day I found an old unused sports wheel, along with its foot pedals, I thought it will be nice to use the pedals to rotate the cube desktop in Linux, just to show off or impress some new customers... well not really.

I have configured my Linux Desktop Effects (I have installed Ubuntu 8.04) this way:
When you press Ctrl + Alt + Right arrow the cube turns right, and
When you press Ctrl + Alt + Left arrow the cube rotates to the left.

So we'll be making a switch to mechanically press the keys in the right order to achieve the effect

This instructable is VERY cheap, but it requires a little bit of work.

Thank you and have fun!

P.S. Some extra pics at: my blog

Step 1: Parts Needed

This instructable is ALMOST the same that

so, most of the steps are the same.

Parts needed:

1) A computer with linux and the rotating desktop cube installed (I have installed Ubuntu 8.04)
2) An unused / old / not working wheel game with pedals, you will only need the pedals. I think it doesn't matter which model is, we will make custom switches
3) An unused old keyboard - for the keys functionality (I had A LOT of unused keyboards at home)
4) Some foamy sheet - I found one at a handcraft shop, you don't even need a full sheet, just a little bit square inches.
5) A multimeter - not a must, but it really helps to check everything OK
6) A soldering iron
7) A dremel tool
8) Some cable, about 10 ft.
9) Plyers, tape, solder, tin foil, scotch tape, etc...

Step 2: Prepare the Pedal

You will need to open the pedal by removing all the screws on the back of the plate, careful because the springs inside will pop all the thing out!

I think this will work for any kind of computer pedals, the process will be almost the same.

Remove all the dust, dirt and also the electronics, we will not use that stuff for this instructable.

Step 3: Make the Pedal Steps...

I like to keep my current Desktop Effects configuration as it is, so, I need to press the Ctr+Alt+Right or Left arrow to get the cube to move.

That means that I nees to press Ctrl and Alt keys first, and then one or another arrow.

So, we will make a simple mechanism to press first 2 switches and then, while holding those, press the other key.

So, we will need to build a kind of foamy sheet ladder to make this cascading chain of pressings.

1) Let's start by gluing a long piece of foamy along the bottom of both pedals.
2) Then, cut another 2 small squares and glue them over the first foamy layer - this squares will press the Ctrl and Alt switches that we will make next.
3) Then, cut another small square, but also cut it to make it half the original height, like if you were slicing some kind of green ham =P

Step 4: Make the Switches...

We will need some kind of office-made srpings.

I used some unused plastic packaging to make 6 "springs", don't know the name, but it's the plastic you can find in the electronic gadgets.

This kind of lastic is very sturdy, I guess it will work for about 10,000 strokes before failing =P

Make 6 of these switches.

The glue 3 to the bottom plate of the right pedal and another 3 to the bottom plate of the left pedal.

Step 5: Take Apart the Keyboard

This step is ALMOST THE SAME from the

so I will just paste the same content so you don't have to go back and forth.

A keyboard works by closing a circuit between 2 plastic layers; when you press a key, the 2 layers get in contact and a current flow between this connection, sending a signal to the microcontroller inside the keyboard.

1) You will have to disassemble the keyboard. Remove all the screws you might find in the back, and release the back cover.

2) Then, remove the thin plastic layers thar are inside the keyboard.

3) then, put the cover on the back and turn the keyboard facing up, to put the layers over the keys to write with a permanent marker where the keys are, one for the upper layer, and one for the bottom layer.

4) We need to find the Ctrl, Alt and Left and Right arrows.

Step 6: Finding Which Pins Works for Our Keys

Then, you will have to find which two pins on the keyboard microcontroller are the ones to be pressed together to close the circuit and send the key code to the computer, so:

1) Take the upper plastic layer (it's glued to the bottom layer, you can use a Xacto knife to cut the small glue spot that puts the 2 layers together.

2) Put one of the multimeter probes at the brown spot, and then put the other probe in the first of the circuit track endings

3) Get the resistance reading in the multimeter (the one with the OHM symbol on it) , if you don't get any reading, move the probe to the next pin in the track endings, until you got some reading.

If you don't have a multimeter don't worry, just follow the track until the ends, just don't get lost because of the tiny lines =P

Once you find where the key ends, do the same procedure for the bottom layer of the keyboard, you need to find the track ending for the Ctrl, Alt and Right and Left arrows.

Make some drawings to remember which pin is for which key.

Step 7: Soldering the Cables in the Keyboard Microcontroller

Ok, so now that we know which pins (or track endings) are the ones for our key, we have to solder some cable in the keyboard circuit.

Before soldering the cables, use the dremel tool to remove the black material over the tracks in the circuit, this will help the solder to stick to the circuit.

Put a little bit solder over the cable, check your drawings to assure you're soldering over the right pins of the microcontroller.

Step 8: Join the Pedal to the Microcontroller

Now, you have to join the pedal cables to the microcontroller cables use the diagram drawings you made to know where to solder the cables.

Apply some solder to the joints to give extra strength.

Then use some electrical tape to insulate the wires.

Step 9: Put the Microcontroller in a Box

Put the circtuit inside a small box.

I had a box from a cell phone, I guess it's the exact size


Step 10: Connect the Pedal and Test It

I used a PS2 to USB adapter to connect the pedal to my computer.

Use the button "Grab key combination" to catch when you press the Ctrl + Alt + Right and Ctrl + Alt + Left

Press "Ok"

and then...

Press the pedal and you should see the Linux cube rotate!!!

Step 11: Done!!!

We have a fancy way to change our desktop in Linux!!!

Thank you for watching!!!