UNDERSTAND the TOUCH!

Imagine your life without cell phone...
What a nightmare!
Don't worry no one is taking the vital thing from you...
Every wondered

                HOW THE TOUCH SCREEN WORKS!

Well lets ponder upon...

There are different technologies for making the touch screen work
The one i ll discuss in this post ll be RESISTIVE TOUCH SCREEN...  Well if u ask me why this first then its because it is least expensive so when i post the next one feel RICHER $$$

RESISTIVE TOUCHSCREEN
is composed of glass panel and PET(Polyethylene terephthalate) film screen each coated with uniform conductive ITO(Indium Tin Oxide) on one side which  is facing each other and having insulating Dot spacers in between.

Working

When screen is touched the pressure causes the ITO coating on PET film to be pushed and touches the ITO coating on glass substrate resulting in electrical contact producing voltage which depicts the position touched.



                                     

  Co-ordinate finding

The pins X(left) and X(right) are on glass substrate and Y(left) and Y(right) are on PET film.

For measuring the X coordinate the microprocessor applies +5V to pin X(left) and the voltage uniformly decreases to 0V at X(right) due to resistive ITO layer and during this the PET film is grounded. The reading on PET film depicts the X coordinate. If the microprocessor detects no voltage it means the screen is not touched however if it is touched, a VOLTAGE on the glass substrate proportional to X coordinate of the touch appears on the PET film.This analog voltage is digitized by A/D converter and stored to transfer to the host, giving X coordinated.

In the next electrical cycle, the Y coordinate is measured in the same way as depicted above only now the +5V is applied to the PET film and reading is obtained from the glass film.

Advantages

• Lowest cost touch technology
• Lowest power consumption
• Can be activated by any object (gloves,finger,stylus,pen etc)

Disadvantage

• Lower image clarity
• Outer film can be damaged by sharp objects.

Keep following my blog so that u don't miss any of the Hi Tech talks!!!



                                      

Not BUILDINGS but INSTRUMENTS!!!

Instrumentation is not a new branch rather has "EVERLASTING FOOTPRINTS"...

Jai Singh II in 18th century was not satisfied with the accuracy of small instruments he said "koi ni lets magnify our instruments" so he built JANTAR MANTAR.

Then came sab instruments ke baap!
3 main instruments are:
1. SAMRAT YANTRA
2. RAM YANTRA
3. JAI PRAKASH YANTRA

1. SAMRAT YANTRA (SUPREME INSTRUMENT): dominating the landscape constructed in 1724 in JAIPUR in essence it is large sundial.


Consists of a triangular ramp or gnomon; to the East and West of the right triangle rise 2 massive quadrants of 15m radial centered on the nearest edges which are calibrated with fine divisions of hours, minutes and seconds.



Simply bole toh

sun rays fall on the right triangle (gnomon) corresponding shadows

are formed on the calibrated radials.

every hour shadow moves 4m so 400/60cm = 6.67cm each minute

further 30 divisions are done so a remarkable accuracy of 2 seconds!!!

Angle of the right triangle???
Simple FUNDA

To measure the local time of a place the hypotenuse of the right triangle (gnomon) should be along the N-S axis.
For example
The latitude of Jaipur is 27 degrees, the local horizon is tilted 27 degrees from N-S axis to form horizon A-B. To compensate for this offsetting a "tilt" angled also at 27 degrees to bring the hypotenuse back in line with the North Celestial Pole.


Shadow formation

sun rises in the east (position C) its shadow on the edge of the western quadrant (D)

As sun moves C-B shadow moves D-E at E it is mid day then sun moves B-A and shadow E-F

this gives the length of the day and by this we can calculate the duration of the night

 
        This shows If u wish u can...
                                                            So think big!
stay in touch for the next big INSTRUMENT! not BUILDING :)
coming soon...

Reference from jantar mantar: the science of indian conjecture