Amazon is a company with a history of taking on challenges and coming out on top. It first launched in 1995, when business on the Web was still in its infancy. It weathered the storms of the bursting dot-com bubble and stayed afloat. What began as a company that sold books is now a massive corporation offering everything from computer hardware to socks. But even as the company evolves, it celebrates its literary roots. In 2007, Amazon introduced the Kindle e-reader. Like other e-readers on the market, the Kindle used electronic ink from a company named eInk to display text and images. Because the device only consumed power when connected to a network or when it had to display a change in pages, its battery could last for more than a week without needing a recharge. Storage space on the device was ample enough to let a user carry thousands of books around. And Amazon's digital book library included an impressive number of titles.
Unlike the original Kindle line of products, the Fire doesn't use eInk. It's a tablet device with an LCD display and the ability to run apps, browse the Web and play video and music. Oh, and you can still use it to read electronic books too. It's comparable in size to the standard Amazon Kindle e-reader. Its design is simple -- on the bottom edge of the device there are two ports and one button. The ports include a micro-USB port for charging and transmitting data over a USB cable and a 3.5-millimeter (0.14-inch) headphone jack. The power button is the only physical button on the Kindle Fire. All other controls for the Kindle Fire are virtual -- you activate them through the capacitive touch-screen interface. Checking under the hood, the Amazon Kindle Fire packs a lot of punch in a small space. A lithium-ion battery provides power. It's a rechargeable battery and one you can't easily replace if it fails.
To get to the battery, you'd have to pry apart the front and back halves of the Kindle Fire's case -- a sure way to void your warranty. The processor for the Kindle Fire is a Texas instruments 1-gigahertz, dual-core microprocessor called the OMAP 4430. You wouldn't see it at first glance -- it's nestled under a 512-megabyte RAM chip from Hynix. These components give the Kindle Fire the ability to access media, process data and accept commands. The processor is like the brain -- it crunches numbers and gets results. The memory stores your media and data needed for apps. The RAM acts as a cache, holding important data so the processor can get to it quickly. The bus is like the nervous system -- it routes data to the appropriate destinations. The transmitter sends data to the Kindle Fire's display and the transceiver allows the device to communicate with a network. The touch-screen controller monitors the Kindle Fire's capacitance screen.
They rely on a weak electrical field to register a touch. Between the glass surface of the Amazon Kindle Fire and the background of the screen is a sandwich of different layers. The base of this sandwich is the LCD display. The layers closest to the screen are conductive layers of transparent material such as indium tin oxide (ITO). These layers create a capacitance grid. The Kindle Fire generates a weak electric field across this capacitance grid. Your finger actually draws current from the field. It's such a weak electric field that you don't sense it yourself. But the Kindle Fire can sense the changes in the field and map them to a specific spot that corresponds to the display screen. The Kindle Fire's software maps the touch to whatever command you were executing. It's easy to understand with an example. Let's say you want to read your copy of "Fahrenheit 451" by the late Ray Bradbury. You recently purchased the book and so it appears on your home screen.
You touch the picture of the book's cover. At that point, the Kindle Fire detects where your finger contacts the screen as the electric field generated across the screen changes. Mapping the location of your touch to the data represented in the icon, the Kindle Fire knows to retrieve and open the copy of the book you've requested. The grid-like structure of the capacitive screen allows the Kindle Fire to detect multiple touches. The grid creates a series of x and y axes that the Kindle Fire relies upon to determine where you're touching and how many fingers you're using. Earlier capacitive screens in electronics relied on capacitors located at the four corners of a screen, which meant the screen could only deal with a single point of contact. A resistive touch-screen interface relies on pressure, not capacitance, to register a touch. When you press on a resistive screen, you cause separate layers under the screen to come into contact with each other, creating a weak circuit.
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