Pitch bend with touchscreen

I wanted to make a real-time pitch bend such as on a keyboard, but with a touchscreen instead of a joystick. I’ve got two ipod screens on the way, but I’m also looking at other options like a DS screen. How should i go about this?

Also nothing about MIDI please. I'd prefer to keep computers out of the equation except for intial programming of course.

So how are you planning on processing the sound? Are you expecting the Arduino to sample the sound, pitch-shift it and play it back out again?

The solutions I can think of are along the lines of touch screen -> PC -> controlling application -> Arduino -> digital potentiometer hacked into a suitable joystick -> keyboard.

This assumes the original working solution used an analog joystick consisting of simple potentiometers and just replaces those potentiometers with something controlled from a touchscreen. Perhaps you could simplify this by putting your controlling application on a touchscreen phone or tablet instead of a PC.

Yes I was hoping for arduino to process the sound for me, if anything already exsists with a joystick I'm fairly sure i could adapt it to a touch screen. I've seen a couple EQ visualizer projects that take the music and play it through an array of LEDs then back out to a speaker so i assume it has the power to do what I'm asking but I just can't find anything on my own