Every day when you prepare to the leave the house, you are confronted with a decision that market analysts and designers drool over, namely, what items do you take with you out of the house?
Let's model this. Presumably you have already in your life accumulated an impressive array of objects. They may fill a whole house, a small apartment, or even just a suitcase. But everyday, from that vast collection, you only really consider taking a small percentage of the objects with you out the door.
And from that small percentage that receives consideration, there is an even smaller number of objects that actually make the cut and wind up on your person or in your bag. Moreover, during the course of the day, an even more select number of items are actually used. These objects, these elite chosen few, are objects of vast interest, not only to handbag designers and the like, but also for anyone interested in understanding human nature.
Maslow's hierarchy of needs, namely food, shelter, and security. Keys are your path to shelter (and in some contexts, transportation), money is your answer to food, and a mobile phone provides a link to friends and family, basically the people you can rely on in moments of distress.
Now this is where the holy trinity really gets interesting. If we are always carrying the minimum three objects, would it be possible to develop just one device that could serve the function of three? Could we have one device that replaces keys, money, and phone?
Ok, we already know that mobile phones are already the tool of the 21st century (pdf). In some countries, for example, minutes on a mobile phone can be sent to another phone, and in this manner bartered, traded, or shared like cash. In these cases, mobile phone operators can function as human ATMs, payroll services, distribution points for charity (i.e. Pyramid of Peace), and invaluable source of news. Here two objects from the trinity, money and phone, have already become intertwined.
As a matter of fact, phone/money mash-ups are ubiquitous in Japan and South Korea. For example, many of you are probably are familiar with the new barcode systems that offer unlimited possibilities to link internet services (including online banking and Paypal) to “real-world” actions, like vending machine purchases or ordering a Big Mac
All the remains in the convergence of the holy trinity is the key/phone integration. This convergence could come in the form of a lock system whose keys can also be stored in a phone. Such a technology is not hard to imagine. There are already quite a few systems that rely on electronic or digital keys, and rigging a phone to unlock these locks no doubt won't be too much of an engineering hurdle.