And the iPhone serves as the base for tens of thousands of third-party applications, many of which make use of its built-in features in innovative ways. Although Apple wouldn’t comment on this story, preferring not to divulge too much about how the ‘magic’ works, we’ve dug around and compiled information from various sources. To take a closer look at how some of the technology inside the iPhone works, read on. Earlier generations of the iPhone were dirt magnets, leaving the screen smudged up after normal use, but the new iPhone 3GS has a protective coating that wards off oily grime.
Amazingly, it works — the 3GS is relatively smudge-free, although it does still pick up dust easily. Gadget blog Gizmodo posted a helpful description from Bill Nye the Science Guy about the oleophobic coating that Apple engineers stuck on the new model’s glass. It is an anti-bonding agent, similar to car wax sealants that cause water to bead, rather than pool, on your car’s roof, Nye explained. The same effect happens with Apple’s polymer coating, preventing the grime from bonding, building and leaving telltale smudges behind.
When you have not used your iPhone for a while, the screen dims to save power. In addition, as you use the phone, brightness adjusts depending on whether you are in sunlight or darkness. Don’t think this is just a timed event based on an internal clock that knows when the sun goes down — it’s not. The iPhone uses an ambient light sensor, describes The New York Times’ David Pogue, in an illuminating 2007 column.
On the iPhone, a chemical-based photocell changes its power setting depending on an infrared reading. On its iPhone site, Apple has revealed some clues about how the touch screen works. A panel under the screen glass senses your touch using an electrical field. The panel then sends this reading to an LCD below it. In other words, your finger changes the electrical charge, which in turn feeds the phone operating system and determines which pixels have changed and which activities have been triggered. When you move the iPhone to your ear, it automatically blanks the screen.
This saves battery power, since you don’t need the screen while talking on the phone (normally), and it also prevents you from touching an onscreen key — such as the one to end a call — by mistake. Based on our own hands-on testing with the device, there are at least two (and possibly three) infrared sensors located near the ear speaker. Like most proximity sensors in smartphones, the iPhone sends out an electromagnetic field that scans for obstructions in an area about a half-inch away from the phone.
Test this by placing an object over one of the sensors. The screen will go blank, and then reappear when you move the object away. Jon Peddie, a consumer tech analyst, explains how the accelerometer works. “The accelerometer knows where the center of the earth is,” Peddie says. Peddie explains that the first accelerometers had tiny magnetic cylinders that could slide from inside one very tightly wound transformer to another nearby, causing the signal in one to go down while the signal in the other went up.
These were called linear voltage displacement transducers. Today, like everything else electronic, the iPhone employs micro-electromechanical systems (MEMS). These devices have tiny (3 microns thick and 125 to 150 microns long) polysilicon arms with small hammer-like blocks on the end. They act like springs and hold the MEMS structure above a substrate. Acceleration causes the arms to deflect from their center position. And just like in the old electro-mechanical devices, the movement of that tiny mass is detected, by capacitors in this case, and a signal is generated.
What we know from hands-on testing is that the iPhone shake feature uses the accelerometer. When it senses the phone has moved (in this case, from side to side), the OS triggers an API call for syncing or a random song. The accelerometer is sensitive enough, says Peddie, to know the difference between a shake and just turning the phone to its side to signal landscape mode.
As long as you are outside and not stuck in a tunnel or inside an office complex, your iPhone can find your exact location using an internal GPS. Like most devices and smartphones with built-in GPS, the receiver in the iPhone can read a signal from a series of orbiting satellites — about three dozen of them — that transmit a near-constant signal. The iPhone receiver reads data from the satellites and figures out — based on how long the transmission takes — the distance to the satellites, and then calculates your location.
0 Comments