Mobile device

A mobile device or handheld device is a computer small enough to hold and operate in hand. Mobile devices are typically battery-powered and possess a flat-panel display and one or more built-in input devices, such as a touchscreen or keypad. Modern mobile devices often emphasize wireless networking, to both the Internet and to other devices in their vicinity, such as headsets or in-car entertainment systems, via Wi-Fi, Bluetooth, cellular networks, or near-field communication.

Device mobility can be viewed in the context of several qualities:

Strictly speaking, many so-called mobile devices are not mobile. It is the host that is mobile, i.e., a mobile human host carries a non-mobile smartphone device. An example of a true mobile computing device, where the device itself is mobile, is a robot. Another example is an autonomous vehicle.

There are three basic ways mobile devices can be physically bound to mobile hosts:

Accompanied refers to an object being loosely bound and accompanying a mobile host, e.g., a smartphone can be carried in a bag or pocket but can easily be misplaced. Hence, mobile hosts with embedded devices such as an autonomous vehicle can appear larger than pocket-sized.

The most common size of a mobile computing device is pocket-sized, but other sizes for mobile devices exist. Mark Weiser, known as the father of ubiquitous computing, referred to device sizes that are tab-sized, pad, and board sized, where tabs are defined as accompanied or wearable centimeter-sized devices, e.g. smartphones, phablets and tablets are defined as hand-held decimeter-sized devices. If one changes the form of the mobile devices in terms of being non-planar, one can also have skin devices and tiny dust-sized devices.

Dust refers to miniaturized devices without direct HCI interfaces, e.g., micro-electromechanical systems (MEMS), ranging from nanometers through micrometers to millimeters. See also Smart dust. Skin: fabrics based upon light emitting and conductive polymers and organic computer devices. These can be formed into more flexible non-planar display surfaces and products such as clothes and curtains, see OLED display. Also, see smart device.

Although mobility is often regarded as synonymous with having wireless connectivity, these terms are different. Not all network access by mobile users, applications, and devices needs to be via wireless networks and vice versa. Wireless access devices can be static and mobile users can move between wired and wireless hotspots such as in Internet cafés. Some mobile devices can be used as mobile Internet devices to access the Internet while moving, but they do not need to do this and many phone functions or applications are still operational even while disconnected from the Internet.