TOUCH SCREEN BASED SPEED
CONTROL OF INDUCTION MOTOR
TYPES OF SPEED CONTROL TECHNIQUES OF
WHY TOUCH SCREEN ??
WORKING OF TOUCH SCREEN
TOUCH SCREEN INTERFACING WITH
DOUBLE REVOVLING FIELD THEORY
ROTATING MAGNETIC FIELD
A touch screen is an electronic visual display that
can detect the presence and location of a touch
within the display area.
Touch screens can also sense other passive
objects, such as a stylus, stirrer etc.
Touch screens are common in devices such as allin-one computers, tablet computers, and smart
The touch screen has two main attributes.
First, it enables one to interact directly with what is
displayed, rather than indirectly with a pointer
controlled by a mouse or touchpad.
Secondly, it lets one do so without requiring any
intermediate device that would need to be held in the
hand (other than a stylus).
They also play a prominent role in the design of digital
appliances such as the personal digital assistant
(PDA), satellite navigation devices, mobile
phones, and video games.
Usually a resistive touch screen consists of at least three
A flexible membrane made from PET film is suspended
over a rigid substrate made from glass or acryl .
Both surfaces are coated with a transparent conductive
film like ITO (Indium tin oxide).
The conductive ITO layers are kept apart by an insulting
spacer along the edges, and by spacer dots on the inner
surface of the two ITO layers.
In this way there will be no electrical connection unless
pressure is applied to the top sheet (PET film).
An A/D converter with a resolution of 10 bits and the
absolute inaccuracy far under the linearity error of the
touch screen is required for the conversion of the
analog values into digital values.
The pins driving the touch screen must be able to sink and
source in the range of 5-25mA
The timer can be used to trigger the ADC and set the I/O
pins in the correct order immediately before a measurement
As mentioned it is possible to determine the force that is
applied on a 4-wire touch screen
By means of Ohms Law there are two different methods
The first method requires a known X-plate resistance and
two additional cross-panel measurements (Z1 and Z2) of
the touch screen.
The second method requires that the X- and Y-plate
resistance values are known but allows the use of a single
measurement only (Z1).methods to determine RTouch
Touch screen position
By making use of this technology, we can control the
equipment in a safe and simpler manner.
It is easy to operate and can be operated by any one.
The danger of electric shock with conventional switches is
also eliminated by using technology.
The power consumed is relatively low compared to
With constant improvement in touch screen technology it
would be more feasible to use touch screen than the
Use of this type of control would make the systems more
reliable and long life.