MHRotaryKnob This is a UIControl that acts like a rotary knob. In operation it is similar to a UISlider but its shape is square rather than long and narrow. HOW TO USE: Copy MHRotaryKnob.h and MHRotaryKnob.m into your project. Add QuartzCore to your target's frameworks. You have to provide the images for the knob and the background. The demo project includes a few basic images but you probably want to use graphics that suit your app's look-and-feel better. (The demo project also includes Knob.xcf, which is the source GIMP file that I used to draw the knob image.) If you want to do more fancy drawing, then you can easily modify the class. Its -valueDidChangeFrom:to:animated: method is invoked whenever the value changes. In the default implementation it simply rotates the knob image. You can change or override this method to do custom drawing. SYSTEM REQUIREMENTS: iOS 3.0 or higher