File:Cell-phone-engineerguy-iPod.ogv

Bill invades a cell phone store to show that the design of a mobile isn't arbritary. Engineers uses seven basic principles to create a useful phone.

Transcript: Transcript I have only a short amount of time to answer this: Why does the cell phone look like it does?

To the untrained eye it seems arbitrary, but seven basic constraints govern the choices made by an engineer in designing a mobile phone.

This hinge embodies the essence of this first constraint ..

... here the engineer captures the essential trade-off of any cell phone: compactness versus usability.

Everyone wants a small phone, but we also want one that fits our bodies - where the keys match the size of our fingertips and a phone we can hold in our hand.

Emotions affect the design of a cell phone.

This flip resonates deeply in the psyche of someone my age. I grew up watching Captain Kirk grab his communicator and bark a command. Beam me up Scotty!

Next, in making a design compact an engineer considers energy. A battery, of course, powers a cell phone, but in the twenty years or so that I've been using a cell phone they've shrunk. Not because batteries improved dramatically, in this case its the infrastructure that constrains the battery size ....

Old cell phones had brick sized batteries. [holds up brick] It took a lot of power to reach a cell phone tower; but today we have such a density of towers that we don't need as much energy to reach the tower. Plus much of the energy-draining computation done by the old phone has been moved to the towers.

That makes this [antenna] an endangered species. Many cell phone no longer have an antenna -- like this one. Here the engineers have built the antenna inside the casing. For this RAZR this [point to small dot on back] is the antenna. This doesn't work as well as a huge external one, but that's, again, the trade-off between compactness and usability

Now, another reason for the phones compactness is plastics. If we didn't have plastics this phone would be much larger and more expensive. Take just this "latch" ....

... imagine how bulky some kind of clasp would be. The fact that plastic gives a little bit and pops back make this simple, small fastener possible. The phone's designer needed a deep knowledge about how this plastic behaves so that it could be used thousands of times without the wearing out.

The insides - the way it operates - reflects yet a sixth design criteria ...

On most modern cell phone you'll E911 (Enhanced 911): In an emergency an operator can locate the phone to within several hundred feet. It doesn't use true global positioning, but "assisted GPS" in that it uses the location of cell phone towers to triangulate. This is fraught with all types of privacy issues: Who should know where you are? Lastly, we need ...