Most electric toothbrushes use batteries and a motor to make it easier to keep your teeth really clean. This toothbrush goes one step further. It uses a separate screen to show you when to move the brush to a different part of your mouth. The screen also lets you know how much longer you need to keep brushing.

The toothbrush itself is a lot like other electric models. It uses a battery to provide power for a small electric motor. The motor turns a gear, which connects to a rod. As the gear turns, it pushes and pulls the rod. This translates the gear's circular motion into a back-and-forth motion.

A series of rods and connectors carries this motion to the toothbrush head. There, it causes the bristles to oscillate back and forth at a high speed.

A printed circuit board (PCB) carries enough electricity from the battery to run several small components. These include integrated circuits, or processors, and a screen. The processors monitor what's happening in other parts of the toothbrush. For example, when you press the "on" button, a switch completes a circuit on the PCB. The processor detects this completed circuit and sends instructions to start the motor. A processor also monitors the battery's charge and tells the screen to display how much electricity is left.

The difference between this toothbrush and many others is that it communicates with an external screen. This screen is pretty simple. It's made of a liquid crystal display (LCD), a PCB, a couple of switches and a processor. The screen's processor does the same work that the ones in the toothbrush do. It monitors circuitry and sends instructions based on what it finds.

The screen and toothbrush communicate using radio waves. These come from small transceivers. There's one on the toothbrush's PCB and a matching one on the screen's PCB.

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Have you ever held one humming tuning fork next to another and heard it start to hum, too? That's a lot like how this toothbrush recharges its battery. There are two metal coils. The first is in the charger and the second is in the toothbrush. Electricity moving through the first coil creates a magnetic field. When you put the toothbrush in the charger, this field produces, or induces, a current in the second coil.