How do touch screen phones work?

Answer 1

To allow people to use touch commands that require multiple fingers, the iPhone uses a new arrangement of existing technology. Its touch-sensitive screen includes a layer ofcapacitive material, just like many other touch-screens. However, the iPhone's capacitors are arranged according to a coordinate system. Its circuitry can sense changes at each point along the grid. In other words, every point on the grid generates its own signal when touched and relays that signal to the iPhone's processor. This allows the phone to determine the location and movement of simultaneous touches in multiple locations. Because of its reliance on this capacitive material, the iPhone works only if you touch it with your fingertip -- it won't work if you use a stylus or wear non-conductive gloves.

The iPhone's screen detects touch through one of two methods: Mutual capacitance or self capacitance. In mutual capacitance, the capacitive circuitry requires two distinct layers of material. One houses driving lines, which carry current, and other houses sensing lines, which detect the current at nodes. Self capacitance uses one layer of individual electrodes connected with capacitance-sensing circuitry.A mutual capacitance touch-screen contains a grid of sensing lines and driving lines to determine where the user is touching.

A self capacitance screen contains sensing circuits

and electrodes to determine where a user is touching.

Both of these possible setups send touch data as electrical impulses. In the next section, we'll take a look at exactly what happens.

The iPhone's processor and software are central to correctly interpreting input from the touch-screen. The capacitive material sends raw touch-location data to the iPhone's processor. The processor uses software located in the iPhone's memory to interpret the raw data as commands and gestures. Here's what happens:

1. Signals travel from the touch screen to the processor as electrical impulses.
2. The processor uses software to analyze the data and determine the features of each touch. This includes size, shape and location of the affected area on the screen. If necessary, the processor arranges touches with similar features into groups. If you move your finger, the processor calculates the difference between the starting point and ending point of your touch.

1. The processor uses its gesture-interpretation software to determine which gesture you made. It combines your physical movement with information about which application you were using and what the application was doing when you touched the screen.
2. The processor relays your instructions to the program in use. If necessary, it also sends commands to the iPhone's screen and other hardware. If the raw data doesn't match any applicable gestures or commands, the iPhone disregards it as an extraneous touch.

All these steps happen in an instant -- you see changes in the screen based on your input almost instantly. This process allows you to access and use all of the iPhone's applications with your fingers.

The shape of the screen changes when you need it to as well -- you can shift the perspective from vertical to horizontal by tilting the phone. An accelerometer inside the iPhone lets the operating system know to change the orientation of the image on the screen. This means that you can scroll through long lists of music files on a long, narrow screen, and you can watch movies in a widescreen format. You can learn more about accelerometers in How the Nike + iPod Works and How the Wii Works.

Answer 2

Pay-as-you-go cell phones offer a great alternative to phone service with a contract. Prepaid companies usually take payment by credit card, monthly refill through a bank account, or a "refill" card. Many companies now offer monthly rates, in which a monthly fee is paid for that month of service. Once the money or time is used up, the phone will not work until it is refilled again.

Answer 3

With a pay-as-you-go phone, you are not bound to the company by a contract. You do need a phone card, however. These cards can be purchased almost anywhere and is comparable to giving the company money toward your account.

Answer 4

Phones work because electricity goes through phone lines and the electricity from the phone lines send energy to every phone in te country.

Answer 5

Mobile phones function by communicating with cell phone towers which communicate with satellites to relay your conversation around the world to where it needs to be.

Answer 6

People purchase minutes in packs. At the end of the minutes, the cell phone stops working. Some plans require an upfront payment before minutes are recharged.