Portable Touch Screen Essay Example

the system using stylus, which Is not very handy. Another similar product is Bluetooth mouse which assists us only to change slides. Apart from these there exists touch screen technologies. There exist basically four screen technologies: Resistive, Capacitive, Infrared and Surface Acoustic Wave (SAW).

The technology SAW. The existing SAW touch screens have two transducers placed along X and Y axis on the touch panel and the reflector, namely glass.

When compared to resistive and capacitive touch screen technologies, SAW is more effective in terms of accuracy, clarity, sensibility, resolution and higher light transmission [1] [2]. The hardware seed in such a touch screen is two transmitting transducers which are affixed perpendicular to each other which transmit SAW, which are reflected by array of glasses placed at an angle of 45 These reflected waves are detected by the receiving transducers placed diagonally opposite to each other as shown. (See figure 1).

Proposed Solution Fig 2: Block Diagram of Proposed Solution The top level block diagram of proposed solution is as shown in figure. (See figure 2). The MINESWEEPER emulation board is used to emit surface acoustic wave of required ramset's.

The wave gets reflected and reaches receivers. The values are converted to digital using DC module of the processor. Digital values are transmitted to PC via Bluetooth module. When touch occurs attenuation happens and as a result the received values are lower than the expected values.

They are processed in PC to set the mouse arrow in the required position.

 The proposed solution aims at the design oaf portable touch screen in a nut shell. Unlike the existing touch screens, it is aimed at mounting the touch screen wherever

the user wants. For e. G.

On a projected screen or desktop display or mobile screen. The design includes mainly 3 parts : 1. The array of SAW reflectors (positioned at 450 to direction of wave travel) [3] which can be mounted in a rectangular fashion. 2. Two SAW transmitters, two receivers and related control units..

Attached to array on sides. ( See figure 3). 3. PC Interfacing circuit. Fig 3: Block Diagram of Proposed SAW Transmitting array Fig 4: Block Diagram of Proposed SAW Receiving array The transmitter array and reflector array can be designed as a strip that can be mounted on wall or desktop screen. The transmitter circuit is.

Transmitter Unit Transmitter Design should meet the following specifications : It should have two SAW It should have array of reflectors (fig 3) Should be portable Design requires a Power Supply.

It requires a EVE - V transformer. Then the AC has to be rectified, filtered and regulated. Hence a proposed power supply circuitry is as shown in figure 5. Transmitter side the requires the SAW Transmitter.