The little magnet on the side is actually a quite creative design feature of the Cardboard headset. It’s a button! Seeing as you can’t touch your phone’s screen while it’s inside the Cardboard, this magnet, when moved, acts as if you’ve pressed your screen. It uses your phone’s magnetometer, which is usually used for compass functions, to sense this and control it while it’s in the cardboard. If your phone does not have a magnetometer then this magnet button is rendered useless. You will have to use an external controlling device like a Bluetooth or USB joystick, keyboard or mouse on your smart phone.
