Samsung-Galaxy-Note-3--volume-button

On popular crowd-funding platforms today are a couple of interesting smartphone add-on accessories. On Kickstarter, we have Pressy, which plugs into the phone’s 3.5mm audio jack and acts as an... extra button. On Indiegogo, there’s Dimple, which is an adhesive strip that contains four buttons that work in conjunction with NFC.

The key functionality in these accessories is the easy...