Internet of Things (AD-604 (A)) - Unit 5 Short Notes

How unit 5 is examined

Unit 5 covers IoT platforms, analytics, cloud and communication APIs, IoT attacks, and case studies; the marks sit in communication APIs and the home intrusion detection design.

IoT Platforms, Arduino, Raspberry Pi Board, Other IoT Platforms

<span style="display:inline-block;padding:.16em .6em;border:1.5px solid currentColor;border-radius:999px;font-size:.68em;font-weight:700;letter-spacing:.06em;text-transform:uppercase;opacity:.75">Not asked since 2022</span>

Definition. <mark>An IoT platform is the hardware and software base that connects devices, collects their data and runs applications on it.</mark>

Key points.

1. Arduino is an open-source microcontroller board (ATmega328P on the Uno) that reads sensors and drives actuators, and it has no operating system.
2. Raspberry Pi is a credit-card-sized Linux computer with a processor, RAM, USB, camera port, Wi-Fi and GPIO pins, so it can run Python, servers and a webcam.
3. Arduino is programmed in C/C++ through the Arduino IDE, has analog inputs and digital pins, and suits simple real-time sensing.
4. Other platforms are ESP8266/ESP32 (cheap Wi-Fi boards), BeagleBone and cloud platforms such as AWS IoT and ThingSpeak.

Data Analytics for IoT, Cloud for IoT, Cloud storage models & communication APIs

<span style="display:inline-block;padding:.16em .6em;border:1.5px solid currentColor;border-radius:999px;font-size:.68em;font-weight:700;letter-spacing:.06em;text-transform:uppercase;opacity:.75">Low weight</span>

Definition. <mark>An IoT communication API is an interface through which devices, gateways and cloud applications exchange data using a defined protocol.</mark>

Key points.

1. REST API is built on HTTP and treats each resource as a URL, using GET, POST, PUT and DELETE; it is stateless and follows the request-response model.
2. WebSocket API keeps one full-duplex TCP connection open, so the server can push data instantly without repeated requests, which suits live dashboards.
3. Request-response suits on-demand reads such as fetching a sensor value; publish-subscribe (MQTT) suits continuous telemetry, because devices publish to a broker and subscribers receive it.
4. Data analytics for IoT turns raw sensor streams into decisions; it is descriptive (what happened), predictive (what will happen) and prescriptive (what to do), run at the edge for speed or in the cloud for scale.
5. Cloud for IoT gives elastic storage, processing and dashboards, so devices need not store data locally; examples are AWS IoT, Azure IoT Hub and ThingSpeak.
6. Cloud storage models are object storage (files and images), time-series or NoSQL databases (sensor readings) and relational databases (device records).
7. Both APIs must be secured with HTTPS/TLS and tokens, since they expose devices to the internet.

Diagram.

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Answer frame. Open with the definition of an IoT communication API; draw the publish-subscribe figure; develop REST, then WebSocket, then the comparison table, then request-response versus publish-subscribe; close with one example, such as a phone using REST to read a temperature that the sensor publishes over MQTT.

Asked: [7 marks] (May 2023) Explain about IoT Communication APIs in detail.

Attacks in IoT system, vulnerability analysis in IoT

<span style="display:inline-block;padding:.16em .6em;border:1.5px solid currentColor;border-radius:999px;font-size:.68em;font-weight:700;letter-spacing:.06em;text-transform:uppercase;opacity:.75">Not asked since 2022</span>

Definition. <mark>An IoT attack exploits a weakness in a device, network or cloud to steal data or take control.</mark>

Key points.

1. Common attacks are eavesdropping, man-in-the-middle, denial of service (Mirai botnet), device spoofing and physical tampering.
2. Vulnerabilities come from default passwords, unencrypted traffic, unpatched firmware and weak authentication.
3. Other attacks are replay attacks, firmware tampering, sinkhole and jamming attacks on wireless sensor networks, and side-channel attacks that read secrets from power use.
4. Vulnerability analysis lists assets, scans for such weaknesses, rates the risk and fixes them with encryption, updates and strong authentication.
5. Countermeasures include changing default passwords, TLS encryption, secure boot, signed firmware updates and network segmentation.
6. Weak points sit at every layer: the sensing device, the network, the cloud and the mobile application.

IoT case studies: Smart Home, Smart framing etc.

<span style="display:inline-block;padding:.16em .6em;border:1.5px solid currentColor;border-radius:999px;font-size:.68em;font-weight:700;letter-spacing:.06em;text-transform:uppercase;opacity:.75">Low weight</span>

Definition. <mark>A home intrusion detection system senses movement, captures an image with a webcam and emails it as an alert.</mark>

Diagram.

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Key points.

1. The PIR sensor detects movement by sensing infrared change and gives a HIGH signal on a GPIO pin.
2. The controller (Raspberry Pi) polls this pin; a webcam on USB is used because Arduino cannot easily process images.
3. On intrusion, the controller captures a frame, saves it as a JPEG and attaches it to the email.
4. The email goes over SMTP with SSL to the owner, who sees the picture immediately; a buzzer can also be sounded.
5. A GET on the controller's web page can also show a live view, so REST and the camera work together in a smart home.
6. Other smart home uses are lights and thermostat control; smart farming uses soil moisture sensors to switch irrigation automatically.

Steps.

Step 1: Read the PIR sensor on a GPIO pin.
Step 2: If motion is detected, capture an image from the webcam.
Step 3: Build an email and attach the image.
Step 4: Send it through the SMTP server to the owner.

import cv2, smtplib
from email.message import EmailMessage
def alert():
    ok, img = cv2.VideoCapture(0).read()
    cv2.imwrite("intruder.jpg", img)
    m = EmailMessage(); m["Subject"] = "Intrusion!"
    m["From"] = "[email protected]"; m["To"] = "[email protected]"
    m.add_attachment(open("intruder.jpg", "rb").read(),
                     maintype="image", subtype="jpeg", filename="intruder.jpg")
    s = smtplib.SMTP_SSL("smtp.gmail.com", 465)
    s.login("[email protected]", "app-password"); s.send_message(m)

Answer frame. Open with one line on the architecture (sensor, controller, webcam, email); draw the block diagram; list the four steps; write the alert function; close with the owner receiving the photo on the phone.

Asked: [7 marks] (May 2023) Design and implement the functionality of a home intrusion detection IoT system by interfacing a webcam. Implement the function in the controller to capture the image from webcam and send it as an attachment in the email alert when an intrusion is detected.

Last-minute revision

• REST is HTTP, stateless, request-response; WebSocket is one persistent full-duplex connection.
• MQTT publish-subscribe uses a broker between publishers and subscribers.
• Arduino has no OS; Raspberry Pi runs Linux.
• Mirai was a DoS botnet built from default-password devices.
• Intrusion alert: PIR, capture image, attach, SMTP send.
• Arduino is a microcontroller in C/C++; Raspberry Pi is a Linux computer with Wi-Fi.
• Analytics types are descriptive, predictive and prescriptive.
• IoT attacks include eavesdropping, man-in-the-middle, DoS, spoofing and tampering.

Memory hooks

• REST asks, WebSocket keeps talking, MQTT broadcasts.
• Arduino = brain only, Pi = tiny computer.
• PIR sees, camera shoots, SMTP shouts.
• DEMS: DoS, Eavesdrop, Man-in-the-middle, Spoof.

Coverage checklist

• IoT Platforms, Arduino, Raspberry Pi Board, Other IoT Platforms: no past questions.
• Data Analytics for IoT, Cloud for IoT, Cloud storage models & communication APIs: IoT communication APIs (May 2023).
• Attacks in IoT system, vulnerability analysis in IoT: no past questions.
• IoT case studies: Smart Home, Smart framing etc.: home intrusion detection (May 2023).