1. The main parts of a scanner are the prism, lens arrangement, and sensor. The prism reflects light from the finger onto the lens arrangement. 2. The lens arrangement focuses and amplifies the reflected light and sends it to the sensor. The sensor converts the light signal into an electrical signal. 3. The electrical signal is sent to the control unit via wires for processing and storage. Additional components like the keypad interface, battery, crystal oscillator, and CMOS battery support operation of the device.

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2. Wires for USB data transfer
and Power by Battery
Capacitor USB Port
Resistors
LCD Screen
CMOS Battery
Wire For Keypad
Interface Wires for
LCD
interfacing
ICs
Crystal
Oscillator
Wire connecting sensor
output to Controlling unit
for further processing
Scanner and Sensor
Speakers

3. Body covering
Prism with flat top Lens arrangement
Scanner surface
The main parts in a scanner is
1. Prism: The top surface of Prism Prism
is flat from where Light is flashed
from LED. On the bottom
surface finger is kept for
scanning.
Scanner
2. Lens arrangement : It is
placed for focusing the
Bottom Surface of Prism where
Lens
reflected light from Prism to the finger is kept for scanning
sensor and amplification
purpose so that it can also
detect in less reflected situation.
3. Sensor : It may be CCD sensor
Lens arrangement
or CMOS sensor or any other
light sensor. Its function is to LEDs in contact with top flat
convert reflected light from surface of Prism
Sensor for receiving reflected
prism into electrical signal which light from Prism placed behind
is transferred by wires and lens arrangement
processed by microprocessors Wire connecting
or microcontrollers in the control sensor arrangement
unit. with controlling unit

4. Keypad Interface
Keypad Interface
Keypad interface is provided
Keys
at the front panel of the
device for giving instruction to
device manually without any
computer such as for putting
device ON or OFF, enrollment
Port for connecting keypad
of new finger, changing date input to main circuit
and time of device etc.
Battery
A rechargeable battery is
put in the device to operate
the device in absence of
any external power source.
For H3I its configuration is
3.7vDC, 1300mAH Battery

5. Device Operation
First the finger is kept on the
prism.
Light from the top flat surface
of the prism strikes the finger
and reflected back at
different intensities and at
different time. These reflected
light consists of information
about minutiae.
This reflected light falls on the lens arrangement which after amplification
focus the light to the sensor.
The sensor convert light signal into electronic signal and sends it to the
control unit where all further procedures takes place.
From Control Unit data is send to data storage device for storage of data
such that it can be extracted further use or communication with another
device.

6. CMOS Battery : Its main function is maintain
power continuity in the memory circuit (RAM)
So that when there is sudden stoppage of
external power supply the temporary memory
data is not lost.
It also provides regular clock pulse to keep the CMOS Battery
chip running so that it can load our previous
settings and can restore date and time every
time the device is switch ON.
Crystal Oscillator : The main function of a Crystal
oscillator is to provide stable clock signal for ICs.
Some Microcontrollers consists of its internal
oscillator they may or may not require external
oscillator but many microcontrollers do not consists
of internal oscillator so crystal oscillator is added Crystal Oscillator
into the circuit to provide stable clock for function
of digital ICs.

7. Thanks