Step 1: Parts List
1 x arduino (any kind of course)
2 x potentiometers (resistance value doesn't matter, mine are 10k ohm)
1 x accelerometer (this is optional, but adds some fun. Mine is only one degree so any will work)
1 x breadboard (not necessarily needed, just makes things easier)
2 x small piece of material approx 5 in by 5 in (wood, cardboard, whatever)
4 x some sort of standoffs for mounting the two pieces of material together
Some lengths of wire to breadboard.
Random tools will also be needed to mount and screw whatever material you're using together.
Step 2: Potentiometers
In order to make them useful, you will need to run a simple test program on the Arduino to find the min (most likely 0) and max values that the potentiometer will have when you call analogRead(pin); I have a sample sketch of this HERE. Just download the "TestPotentiometer" file and run it in arduino. Make sure you have the potentiometer in the first analog port (A0). Record these max and min values as you will have to enter them in the processing program for accurate readings!
Step 3: Accelerometer
Step 4: Arduino
Step 5: Processing
Next you will need my processing sketch which is available HERE. Once you have my sketch open, click the run button and if the Etch A Sketch frame pops up you are good to go! If not, check to make sure you correctly loaded the Arduino program and Processing library.
To ensure beautiful drawings, insert the max and min values you found for the potentiometers' into the 5th line of code where it says
"int min1 = 0, min2 = 0, max1 = 1023, max2 = 1023;"
For the accelerometer put your max vallue into the line that reads "int MAX_ACCEL = 624;"
Step 6: Controller
Take the top piece of material and mark two holes for your potentiometers. You will want to make them large enough for the middle part to stick through but not too large that the lock ring won't hold it in place. Then cut a hole and mount these (if confused look at the side view of them mounted below). Now wire everything up to the breadboard. Ground wire's to ground, power wires to 5v, and signal wires to analog ports. You'r "left" pot (the one your left hand will change when you hold it) should be in port a0, the "right" pot should be in a1, and the accelerometer should be in a2.
Screw on the top the layer to the standoffs and you're done! Go crazy. Actually, not too crazy.
Step 7: Results
Go nuts, but really make it put out rainbows or pictures of your grandmother. Do something neat and send me a pic of the results! This controller you made could also be used for many other programs (2 player pong perhaps? Or if you're especially nuts then an asteroids type game?). I was thinking I'd really like to project this onto the side of a building and let passerby's have a go. Could be lots of fun!
I hope you enjoyed the instructable and it got you thinking!