By Andrew Liszewski
I’ve got nothing against touchscreens, they’re great for most applications, but they’re not always the ideal alternative to a physical button, slider, knob or even scroll wheel. So I like this clever compromise that dsLabs have come up with. Using the same principles people have used to create capacitive touchscreen-friendly styluses, they’ve created a touchscreen-friendly knob that allows you to rotate objects on the iPhone/iPod Touch/iPad by rotating the knob while it’s sitting on the screen.
And making your own doesn’t seem to be that difficult. It just requires a bit of trial and error and some extra care to ensure the knob you’ve re-appropriated doesn’t scratch up the display.
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.