Hand Held Gadget

A few decades ago mobile telephones were the stuff of science fiction, like the communicators used in Star Trek, but since February 2009 there have been more than 4 billion subscriptions to mobile phone services. Mobile phones are globally ubiquitous.

The mobile phone pictured left was used for 3 different functions; as a telephone, as a pocket watch and as an alarm clock. So effectively it replaced the items on the right.

Some things a smartphone can replace Today this mobile is used as a torch, telephone, pocket watch, alarm clock, music player (mostly podcasts), sat' nav, camera, radio, notebook, address book, calendar and calculator.

Smartphones have combined the functions of a PDA and a mobile phone. The vision of this video , a portable device that can also be used as a desktop computer, was being followed by Windows 10 Continuum and is being followed by Samsung DeX which could, possibly, be seen as the future of personal computing.

Things a smartphone can replace

Add in some things that it could be used as and you have the picture on the left.
A video camera, stills camera, torch, telephone, modem, alarm clock, star chart, compass (will only work if the device has a magnetometer), music player, sat' nav', pocket watch, dice, pocket games console, sound level meter, dictaphone, radio, stop watch, notebook, address book, calendar and calculator. 21 items!
You could also add maps, maybe a spirit level and a seismometer?

What other physical objects might smartphones be able to replace in the future?
Credit cards, house keys and car keys all using NFC. Also tickets such as Electonic Boarding Passes.

The list gets longer when you add the things a tablet can be used as: A portable DVD player and a pile of DVDs, an Argos catalogue, a dictionary, Yellow Pages and Thomson Local, video camera, stills camera, telephone, pocket watch, dice, sound level meter, a weeks worth of newspapers, a photo album, TV guide and remote control, star chart, pocket games console, modem, alarm clock, torch, stop watch, notebook, address book, calendar, calculator, dictaphone, compass, sat' nav', radio and music player. 30 or more items!

A mobile is obviously very useful. It has many functions, those functions are available whenever its to hand (for some functions a 'signal' is needed too) and the burdens are fairly low - the purchase cost, keeping it charged and the cost of the monthly bill.

Usefulness = (Functionality x Availability) – Burden