Cards And Sensor

1. CARDS AND SENSORS
SMART CARDS
Smart cards (or Integrated Circuits cards or ICC) are small pocket-sized cards with
electronic processing circuits embedded in them. Some memory cards and some have
embedded microprocessor circuits.
Smart cards are divide into two:
 Contact smart cards : They have gold coated pins on the chip that provide contact
with the electrical circuits of the card reader when the card is inserted in it.
Eg telephone cards in public telephones.
 Contact-less smart cards: They communicate with card readers using the radio
frequency induction technology. These cards have to be held close to the reader’s
antenna.

2. The chip embedded in a smart card is a circuit including a computer, memory and
transceiver. The chip lies in between the inner layers of the card.
Smartcards do not have batteries. The energy is provided by the card reader.
The computer in the card is activated by power (through radiation in a contact less card
and through the IC pins on the card surface in a contact card) from a nearby reader called
host.
The card communicates with the host after appropriate interchanges for authentication.
Application protocol data unit(APDU) is an accepted standard for card-host
communication.

3. Applications of smart cards:
 For financial transactions as a credit or ATM / debit card.
 Can store personal id or medical reports.
 An employee can use it to open security locks at work and log in.
 A student uses it to get books issued from library.

4. SENSORS
Sensors are electronic devices that sense the physical environment; for eg: there are
sensors for temperature, pressure, light etc.
The sensor sends the signals to a computer or controller.
A sensor maybe a CCD(charge coupled device) camera to identify various objects or a
microphone to recognize voices. Sensors in a mobile device facilitate interaction of the
device with the surroundings.
Smart sensors have computational, communication, and networking capabilities.
It consists of the sensing device, processor, memory, analog to digital converter(ADC),
signal processing element, wireless or infrared receiver and transmitter, and performs
communicational and computational functions.
Sensors are programmed using assembly language or C.

5. Examples of sensors:
 Sensor for surrounding light can be used to control the brightness of the LCD
screen.
 Sensor for measuring the strength of the signal received, controls the amplification
of received signals.
 Sensor for background noise can be used to control voice amplification during a
call.
Examples of sensors used in robotic systems:
 Acceleration and force sensors in the right and left feet
 Infrared distance sensors at the head and hands
 Microphones in ears etc.