The same folks behind this "soft stylus" we showed you have another DIY project that will add some new functionality next to the finger sliding and pinching you're used to: spinning. With this simple knob, you're able to rotate objects and images on the screen.
The trick to it is making a knob that registers without scratching:
Similar to the soft stylus, the trick is finding a way to create a conductive path from your hand to the screen. We started by using copper tape, conductive fabrics (see the soft stylus) and wires to simulate two touch points on opposite sides of the knob. It takes some careful tuning to get the touch points spaced correctly and sized such that the screen reads them as a touch, but it does work with a little patience.
It's a cool effect: