Technology Unleashed

The Touch Works Like This :

• when you place your finger or a stylus on the screen, it changes the state that the device is monitoring.
• In screens that rely on sound or light waves, your finger physically blocks or reflects some of the waves. 
• Capacitive touch screens use a layer of capacitive material to hold an electrical charge; touching the screen changes the amount of charge at a specific point of contact. 
• In resistive screens, the pressure from your finger causes conductive and resistive layers of circuitry to touch each other, changing the circuits' resistance.

  

The Apple iPhone is different. Many of the elements of its multi-touch user interface require you to touch multiple points on the screen simultaneously.


Actually the iphone processes touch informations in this manner:

• Signals from the screen travels to the processor as electric pulses.
• The processor determines size, shape and location of the affected area on the screen. 
• The processor also 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.
• 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.
• The processor relays your instructions to the program in use. 
• It also sends commands to the iPhone's screen and other hardware. 

  

  



All these steps happen in a nanosecond.