One of the most helpful presentation for academic and non academic purpose. This presentation can be presented for 40-45 mins. It contains both technical and non technical details of working of a fingerprint bio-metric scanner.

1. FINGERPRINT
BIOMETRICS
ESD PRESENTATION
GROUP 2

2. BIOMETRICS
• Biometrics (or biometric authentication refers
to the identification of humans by their
characteristics or traits. Biometrics is used in
computer science as a form of identification
and access control. It is also used to identify
individuals in groups that are under
surveillance

3. TYPES OF BIOMETRICS
• DNA MATCHING
• EAR
• EYES-IRIS RECOGNITION
• VOICE RECOGNITION
• FACE
• FINGERPRINT RECOGNITION
• FINGER GEOMETRY RECOGNITION
• SO ON….

4. WHY FINGERPRINTS
• Very high accuracy.
• Is the most economical biometric PC user
authentication technique.
• it is one of the most developed biometrics
• Easy to use.
• Small storage space required for the biometric
template, reducing the size of the database
memory required
• It is standardized.

5. IT’S AN EMBEDDED SYSTEM!!!!!

6. BASIC ELEMENTS OF A TYPICAL
FINGERPRINT BIOMETRIC SYSTEM
• Sensing
• Processing
• Storage
• Interface

7. Biometrics System Elements

8. THE SENSOR

9. Types of Sensors
Optical
Capacitive
Thermal
Pressure

10. OPTICAL
• Heart of an
optical sensor is a
Charged Couple
Device ( CCD): an
array of light
sensitive diodes
called photosites
which generate
an electrical
signal in response
to light photons.

11. Working
• Photosite records pixels.
• Ridges and valleys present on fingers are illuminated
• CCD processor ensures a clear image is taken
• Definition of the image is checked
• Collectively pixels form an image
• A to D Converter generates digital representation of image

12. How capacitive touch
works

13. Frequency Change method
• An oscillator that oscillates
at a high frequency (usually
10 to 50 KHz), and uses a
capacitor to oscillate.

14. 555 multivibrator Capacitance of 10pF
(Body capacitance is about
15pF)
Note :
We use a small capacitance of 10pF because the body capacitance is small as well, usually
from 8 to 15 pF.
So, the capacitor C must be around this value, so that the body capacitance will have a big
influence to the overall capacitance.

15. • The touch sensor is placed in parallel with this capacitor, or some
times the touch sensor is the capacitor itself.
• If the touch sensor is touched by a finger, then the body capacitance
is connected in parallel to the sensor's capacitance.

16. • As you may know, the overall capacitance of two capacitors connected in parallel is
increased (connecting capacitors), and this causes the oscillating frequency to
change (bigger capacitor means lower frequency).

17. Before detecting touch After detecting touch

18. • Using a digital comparator or any other method to sense this frequency change,
one can determine if the touch pad is touched.

19. The frequency comparator –
• There are several ways to implement such a circuit.
• One of them, is to convert the frequency into a DC voltage with a
Frequency to Voltage converter, and compare it to a fixed DC voltage.
This method is widely used in analog applications.

20. The output stage –
• A Schmidt trigger compares the output values from the frequency
comparator & it’s output leads to the LED which glows when a touch
is detected.

21. Capacitive Voltage Divider method
• This is another very interesting
technique to implement a touch
sensor.
• The touch pad is directly connected to
the Analog to Digital converter of a
microcontroller.
• Here is a rough diagram of the circuit:

22. • The ADC module is internally driven to VDD, so that the
capacitor used for the A/D conversion is fully charged
• The analog input (sensor) is internally disconnected
from the ground
• The ADC module is internally connected to the Analog
Input (sensor)
• The analog input (sensor) is internally grounded, so that
the sensor is fully discharged

23. • Internal capacitor will discharge part of its charge to the sensor (or human
body).
• At the end, both capacitors (the internal and the sensor) will have the
same voltage across them. This voltage depends on the capacitance of the
sensor.

24. • When the voltage is divided, it will be times smaller than the original charge
of the internal capacitor.

25. • So, immediately after step 4, the microcontroller starts an analog to
digital conversion and reads the ADC module registers.
• According to the voltage that it reads, it can be determined if the
sensor is touched or not.

26. • This method is extremely simple to implement with a microcontroller, because
the only external part required is the sensor. It is completely improper to
implement without a microcontroller.

27. THE PROCESSOR

28. WHY DSP OVER MC
• A programmable processor like the DSP can
address all the processing needs of a biometric
system while providing the most viable path to
standards and feature upgrades.
• A DSP allows the product to be small and
portable while maintaining power-efficient
performance all at a low overall system cost.

29. • The DSP architecture is built to support complex
mathematical algorithms that involve a significant
amount of multiplication and addition.
• The DSP executes the multiply/add feature in a
single cycle (compared to multiple cycles for RISC
processors)
• In addition, the Harvard architecture of the DSP
(multiple busses) allows instruction and operand
fetches in the same cycle for increased speed of
operation.

30. BASIC BLOCK DIAGRAM

31. GENERAL PURPOSE
INPUT/OUTPUT (GPIO)
• It is a generic pin on a chip whose behavior (including
whether it is an input or output pin) can be controlled
(programmed) by the user at run time.
• GPIO pins have no special purpose defined, and go
unused by default. The idea is that sometimes the
system integrator building a full system that uses the
chip might find it useful to have a handful of additional
digital control lines, and having these available from
the chip can save the hassle of having to arrange
additional circuitry to provide them.

32. THE SERIAL PERIPHERAL INTERFACE
SPI-BUS
• It is a simple 4-wire serial communications
interface used by many
microprocessor/microcontroller peripheral
chips that enables the controllers and
peripheral devices to communicate each
other. Even though it is developed primarily
for the communication between host
processor and peripherals, a connection of
two processors via SPI is just as well possible.

33. SPI BUS

34. • An SPI protocol specifies 4 signal wires.
• Master Out Slave In (MOSI) - MOSI signal is generated by
Master, recipient is the Slave.
• Master In Slave Out (MISO) - Slaves generate MISO
signals and recipient is the Master.
• Serial Clock (SCLK or SCK) - SCLK signal is generated by
the Master to synchronize data transfers between the
master and the slave.
• Slave Select (SS) from master to Chip Select (CS) of slave -
SS signal is generated by Master to select individual
slave/peripheral devices. The SS/CS is an active low signal.

35. • The SPI bus, which operates at full duplex
(means, signals carrying data can go in both
directions simultaneously), is a synchronous
type data link setup with a Master / Slave
interface and can support up to 1 megabaud or
10Mbps of speed. Both single-master and
multi-master protocols are possible in SPI.

36. • To begin a communication, the bus master first
configures the clock, using a frequency less than
or equal to the maximum frequency the slave
device supports. Such frequencies are commonly
in the range of 1–100 MHz.
• During each SPI clock cycle, a full duplex data
transmission occurs:
• the master sends a bit on the MOSI line; the slave
reads it from that same line
• the slave sends a bit on the MISO line; the master
reads it from that same line

37. A typical hardware setup using two shift
registers to form an inter-chip circular buffer

38. IMAGE ENCODING

40. STORAGE ELEMENT
• The function of the storage element is to
store the enrolled template that is recalled to
perform a match at the time of authentication.
• DSPs have varying sizes of internal RAM to
address the image processing and template
extraction processes of the various biometric
algorithms, along with read-only memory (ROM)
for storing the constant parts of the programming
code.

42. LDO
• A low-dropout or LDO regulator is a DC linear
voltage regulator which can operate with a
very small input–output differential voltage.
• The advantages of a low dropout voltage
include a lower minimum operating voltage,
higher efficiency operation and lower heat
dissipation.

43. COMPONENTS OF LDO
• The main components are a power FET and a
differential amplifier (error amplifier).
• There are two inputs to the differential
amplifiers.
• Low-dropout (LDO) regulators work in the
same way as all linear voltage regulators.
• The main difference between LDO and non-
LDO regulators is their schematic topology.

44. ESD PROTECTION
• Electrostatic discharge (ESD) is the sudden
flow of electricity between two objects caused
by contact, an electrical short or dielectric
breakdown.
• . ESD can be caused by a buildup of static
electricity by turbocharging, or by
electrostatic induction.

45. CHARACTERISTICS OF THE PROTECTION
Extremely fast response time
Low clamping and operating voltages
Capacity to handle high peak ESD currents
Ability to remain undamaged by repetitive ESD
strikes
Minimal size

46. BASIC BLOCK DIAGRAM

47. FUTURE PROSPECTS
• Public Sector Application : eBorders, eID,
and eGovernment.
• Commercial Application : Enterprise
Security, Information Transactions,
Financial Transactions.
• Technology Evolution : Secure Identity
Core, Secure Mobility, Secure
Credentials, and Secure Transactions.

48. EXAMPLES