A wearable computer , also known as a body-borne computer , is a
computing device worn on the body. The definition of 'wearable computer' may
be narrow or broad, extending to smartphones or even ordinary wristwatches.
Wearables may be for general use, in which case they are just a particularly
small example of mobile computing. Alternatively, they may be for specialized
purposes such as fitness trackers. They may incorporate special sensors such
as accelerometers, heart rate monitors, or on the more advanced side,
electrocardiogram (ECG) and blood oxygen saturation (SpO2) monitors. Under the
definition of wearable computers, we also include novel user interfaces such
as Google Glass, an optical head-mounted display controlled by gestures.