If you have ever used a touch screen then you must know this

Besides gaining huge popularity as touchscreen phones, touch screen are also found in ATMs, Airport etc. Why not to know the very basic science of it then? So here’s what Wiki and HowStuffWorks teach us, explained at Tech Affairs for the layman.

Touch screen are made of varied technology but the back bone comes from three techniques widely developed and used.

1. Resistive Type:      The resistive type of touch screen has two layers, one resistive and the other conductive. Whenever the screen is tapped with a stylus or fingers, the two layers make contact with each other and a voltage difference is created. The voltage difference judges the coordinate and the position of the screen being touched are responded.

2. Conductive Type:   A sheet of conductor is such set up so that it carries an electric field. Whenever the screen is touched the electric field is disturbed at a particular coordinate, the location of change in electric field is the location of touch.

3. Surface acoustic wave:      This technology is used in touchscreen phones. On the screen two transducers are designed that converts physical variation into electrical signals. One transducer at the x coordinate and other at the y. Whenever a touch event occurs the transducer can detect the change in wave and a signal is sent from one transducer (may be of x or y coordinate) to the other and the signal judges the coordinate point where the screen was touched.

Surface Acoustic Wave technology has gained more momentum then the other two technologies mentioned above because unlike the other two, Surface Acoustic produces far clearer and bright display making it suitable for phone use. Resistive and Capacitive transmits 70% and 90% light respectively. Also the Surface Acoustic type doesn’t have metallic layer on the screen.

The very basic about GPS enabled cellphones

If you carry a smartphone then most probably you have a GPS receiver embedded in it. OVI maps in Nokia phones or the Goggle maps pinpoint your location instantly. It gives information on your present location, restaurants near you etc.

A mobile phone network consists of a base station and a tower. Whenever you (your phone) move from one network to another, the base station of the respective network determines the signal strength. The tower transfer the signal from one base station to other depending upon the strength of the signal at a particular base station.

GPS in a smartphone can use two way methods to determine your location. It may scan for nearest towers in the phone’s vicinity. Determining the signal strength, the angle of approach and distance of the phone from the towers a location of the phone can be fixed, but this method is not the actual task of a GPS receiver. A GPS receiver in a smartphone actually scans for three satellites in the sky below which the GPS receiver is present, now a location of the GPS receiver is fixed by determining its location relative to the three satellites. The point where the end point of the waves from these satellites intersects on the surface of the earth is the location of the device. This technique is known as triletaration. Both the method mentioned above are used by smart phones simultaneously for better accuracy of the location.

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