Mobile Computing, RFID, Biometrics and Green Computing

Hello students, welcome to Kwickprep. A car crosses a highway toll plaza without stopping, and the toll is paid. You unlock your phone with a fingertip. What technology makes this possible? Today we will learn mobile computing and the generations of mobile networks, RFID, biometric recognition, and green computing.

Let us begin with mobile computing. Mobile computing means using a computer and its data while you are moving from place to place. The devices are portable, like smartphones, tablets and laptops. They connect through wireless networks, like mobile data or Wi-Fi, so no cable is needed. Paying by UPI at a shop, following a map, or joining a video call on a bus are all mobile computing.

A generation, written with a G, is a stage in the growth of mobile network technology. 1G used analogue signals and carried voice calls only. 2G made voice digital and added SMS text messages. 3G brought mobile internet for browsing and email, and early video calls. 4G gave fast broadband, so we could stream HD video and use apps smoothly. 5G is very fast with very low delay, and it was launched in India in October 2022.

You heard the words low delay, so let us explain latency. Latency is the small delay between sending data and it reaching the other side. When latency is low, live actions like online games and video calls feel instant. That is why 5G is useful for remote controlled machines, smart factories and future self driving cars.

Mobile computing has advantages and limitations. You can work and learn from anywhere, even from a village with a signal. You get instant payments and information. But it depends on network coverage and battery life. And if a phone is lost or stolen without a screen lock, personal data can leak.

Now RFID, which stands for Radio Frequency Identification. It identifies objects using radio waves. An RFID tag is a tiny chip joined to an antenna, and it stores a unique number. An RFID reader sends out radio waves and receives the data sent back by the tag. Unlike a barcode, the tag does not need to be touched or even seen, so it can be read from a distance.

FASTag on Indian highways is a great RFID example. The reader at the toll lane sends out radio waves. The FASTag sticker on the windscreen replies with its unique ID. The system asks, is there enough balance in the linked account? If yes, the toll is deducted and the barrier opens. If no, the car is stopped, and the driver must pay, usually a higher toll.

There are two main types of RFID tags. A passive tag has no battery and takes power from the reader's radio waves, while an active tag has its own battery. So a passive tag works over a short range, while an active tag can be read from far away. Passive tags are cheap, and active tags cost more. FASTag and library book tags are passive, while tags that track shipping containers are often active.

Next, biometrics. Biometric recognition means identifying a person by measuring features of their body or behaviour. Physical features include fingerprints, the face, and the iris, which is the coloured part of the eye. Behavioural features include the voice, the way you sign, and even your typing style. In India, Aadhaar authentication can use your fingerprint, iris or face to confirm who you are.

Here is how a fingerprint lock decides. First, the sensor scans your finger. The software turns the ridge pattern into a template, which is a set of numbers, not a photo. It compares this with the template stored when you registered. If they match, the phone unlocks. If not, it refuses and asks you to try again.

Biometrics also has advantages and limitations. You have nothing to remember or carry, unlike a password or a card. It is hard to share or guess, so it is more secure. But it can fail, for example when fingers are cut or worn from hard work. And if biometric data is stolen, you cannot change your fingerprint like a password.

Pause and predict. Your school ID card has an RFID chip inside. Is tapping it at the gate a biometric check? The answer is no. The card is RFID, because it identifies the card, not your body, while a face scan would be biometric.

Finally, green computing. It means designing, using and disposing of computers in a way that harms the environment as little as possible. Save energy by using sleep mode and switching off monitors and computers when not in use. Buy energy efficient devices, such as those with high star ratings. Give old devices to authorised e-waste recycling centres, because they contain harmful metals like lead and mercury. Print only when needed, and share servers through the cloud instead of running many half empty machines.

Why does this matter? Data centres that run apps and the cloud use a huge amount of electricity. India is among the largest producers of electronic waste in the world. Using less energy means lower electricity bills and less pollution for everyone.

Let us revise. Mobile computing means using computing while on the move. Networks grew from 1G voice calls to 5G with very high speed and low delay. RFID uses a tag and a reader that talk by radio waves, like FASTag. Biometrics identifies people by features like fingerprints, iris and face. Green computing saves energy and recycles e-waste safely.