A wearable computer is a small portable computer that can be carried by a single person and used during other activities. Wearables typically have some head-mounted display device, an input device that can be operated with one hand such as a chord keyboard, and a processing unit and power supply attached to a belt or backpack. They are usually powered by batteries or fuel cells, but some models may use solar power, or even some device to tap the mechanical power of the wearer.
Some may use a more specific definition, such as Steve Mann's, which includes such properties as operational constancy (the property that the computer is always on and ready for use).
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