Embedded systems and iot preview

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Unit 1

Embedded systems is combination of hardware and software that perform specific task

1. 8-Bit Embedded Processor

  • A processor used in embedded devices to do specific tasks.
  • Works on 8 bits of data at a time.
  • Example: 8051 microcontroller.

2. 8-Bit Microcontroller Architecture

  • A microcontroller is a single chip with:
    • CPU: executes instructions.
    • ROM/Flash: stores the program.
    • RAM: stores temporary data.
    • I/O ports: connect to external devices.
    • Timers/Counters: measure time or count events.
    • Serial Port: communicate with other devices.
    • Interrupts: handle urgent tasks.

3. Instruction Set and Programming

  • The list of commands the microcontroller can execute.
  • Examples:
    • MOV: move data.
    • ADD: add two numbers.
    • CLR: clear a bit.
    • SJMP: jump to another part of the program.
  • Programs are written using these instructions in Assembly or C.

4. Programming Parallel Ports

  • Parallel ports have 8 pins to send or receive 8 bits at once.
  • Used to control LEDs, motors, or read switches.
  • Example:
    • Write data to port → turn ON LEDs.
    • Read data from port → check switch status.
  • 8051 has ports P0, P1, P2, P3.

5. Timers

  • Built-in counters that count clock pulses.
  • Used to create delays, generate signals, or measure time.
  • 8051 has Timer 0 and Timer 1.

6. Serial Port

  • Used for communication between devices one bit at a time.
  • Example: send data to a PC or receive from a sensor.
  • 8051 has a built-in serial communication unit (UART).

7. Interrupt Handling

  • An interrupt pauses the main program to handle a high-priority task.
  • After finishing, the program resumes.
  • Example:
    • Timer overflow interrupt.
    • External interrupt when a button is pressed.
    • Serial interrupt when data is received.
  • The response to an interrupt is written in an Interrupt Service Routine (ISR).

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1. Memory and I/O Devices Interfacing

  • Memory interfacing: Connecting external RAM/ROM to the microcontroller so it can read/write data.
  • I/O interfacing: Connecting input/output devices (like sensors, LEDs, displays, motors) to the microcontroller so it can control them or read their status.

2. Programming Embedded Systems in C

  • Embedded systems are programmed using the C language because:
    • It is close to hardware (like Assembly).
    • It is easy to write and maintain.
  • We write C code to:
    • Read/write from ports.
    • Control timers, interrupts, and serial communication.

3. Need for RTOS (Real-Time Operating System)

  • RTOS is needed when many tasks must run at the same time in a time-sensitive way.
  • Example: In a washing machine, one task controls water flow, another runs the motor, another checks the door — all need to run together.
  • RTOS helps manage and schedule these tasks properly.

4. Multiple Tasks and Processes

  • Task: A small program that does one job.
  • Embedded systems often run multiple tasks (like reading sensors, updating display, sending data).
  • The system switches between tasks very fast, so it looks like they run at the same time.

5. Context Switching

  • When the CPU stops running one task and starts another, it saves the current task’s status (called its context).
  • This is called context switching.
  • When the first task resumes, its context is restored.

6. Priority-Based Scheduling Policies

  • When many tasks are waiting, the RTOS decides which task to run first.
  • Tasks can have priorities (high or low).
  • The scheduler always runs the highest priority task first.
  • Example: A fire alarm task has higher priority than updating the display.

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1. Introduction to the Concept of IoT Devices

  • IoT (Internet of Things) devices are objects that can connect to the internet and share data.
  • Examples: Smart bulbs, fitness bands, smart door locks.

2. IoT Devices Versus Computers

  • IoT devices are simple, low-power, and designed for one job.
  • Computers are powerful, multitasking machines.
  • IoT devices are cheaper and smaller than computers.

3. IoT Configurations

  • Configuration means setting up IoT devices for communication and function.
  • Types:
    • Device to device
    • Device to cloud
    • Device to gateway
  • You configure WiFi, Bluetooth, IP address, etc.

4. Basic Components

  • Sensors: collect data (temperature, light).
  • Actuators: take action (motor, buzzer).
  • Microcontroller: processes data (like Arduino).
  • Connectivity: sends data (WiFi, Bluetooth).
  • Power supply: battery or adapter.

5. Introduction to Arduino

  • Arduino is an open-source microcontroller board used for building electronics projects.
  • It is beginner-friendly and supports sensors, motors, displays, etc.

6. Types of Arduino

  • Arduino Uno (most common)
  • Arduino Mega (more pins and memory)
  • Arduino Nano (small-sized)
  • Each type is used based on project size and requirements.

7. Arduino Toolchain

  • Toolchain = all tools needed to program and upload code to Arduino.
  • Includes:
    • Arduino IDE (coding software)
    • Compiler (translates code)
    • Uploader (loads code into Arduino)

8. Arduino Programming Structure

  • Arduino code has two main parts:
    • setup() – runs once at the start.
    • loop() – runs again and again forever.

9. Sketches

  • A sketch is the name for an Arduino program (code file).
  • Written in Arduino IDE using C/C++.

10. Pins Input/Output from Pins Using Sketches

  • Arduino has digital and analog pins.
  • Input: Read from buttons, sensors.
  • Output: Write to LEDs, motors.
  • Example in sketch: 
    digitalWrite(13, HIGH); // turns ON LED at pin 13

11. Introduction to Arduino Shields

  • Shields are add-on boards that plug into Arduino.
  • Used to add features like WiFi, GPS, LCD.
  • Makes hardware expansion easy.

12. Integration of Sensors and Actuators with Arduino

  • Sensors give data to Arduino (temperature, motion, etc.).
  • Actuators do actions based on that data (run fan, sound buzzer).
  • Example: Temperature sensor reads value → Arduino turns on fan.

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1. IoT Communication Models and APIs

  • Communication models define how devices talk to each other.
  • Common models:
    • Device-to-Device
    • Device-to-Cloud
    • Device-to-Gateway
  • APIs (Application Programming Interfaces) allow different devices and apps to interact and share data.

2. IoT Communication Protocols

  • Protocols are rules for how data is sent/received.
  • Examples:
    • HTTP – for web-based communication
    • MQTT – lightweight protocol used in IoT
    • CoAP – designed for low-power devices

3. Bluetooth

  • Short-range wireless communication.
  • Used for pairing devices like smartwatches or fitness bands.
  • Low power consumption.

4. WiFi

  • Wireless network used for internet access.
  • Used in home automation, smart appliances.
  • High speed and range.

5. ZigBee

  • Low-power wireless protocol for short-range communication.
  • Used in smart homes (like smart bulbs, sensors).
  • Better battery life than WiFi.

6. GPS

  • Global Positioning System – gives exact location using satellites.
  • Used in vehicles, trackers, and maps.

7. GSM Modules

  • GSM (Global System for Mobile) – allows devices to send SMS, make calls, or use mobile data.
  • GSM modules (like SIM800) can be added to Arduino/Raspberry Pi.

8. Open Platform (like Raspberry Pi) Architecture

  • Raspberry Pi is a low-cost, credit-card-sized computer.
  • Has:
    • CPU
    • RAM
    • USB, HDMI, WiFi
    • GPIO pins
  • Can run Linux and support programming in Python/C++.

9. Programming

  • Raspberry Pi is usually programmed using Python.
  • Code controls sensors, motors, sends data to cloud, etc.

10. Interfacing

  • Interfacing means connecting sensors/actuators to Raspberry Pi.
  • Example: Connecting temperature sensor to GPIO pin.

11. Accessing GPIO Pins

  • GPIO (General Purpose Input Output) pins are used to connect external devices.
  • Used to read sensor data or control LEDs, motors.

12. Sending and Receiving Signals Using GPIO Pins

  • You can use code to:
    • Send signal: turn on LED, motor
    • Receive signal: read button press, sensor data
  • Example in Python: 
    GPIO.output(17, GPIO.HIGH)  # Turns ON pin 17

13. Connecting to the Cloud

  • Cloud is used to store, monitor, and control data from IoT devices remotely.
  • Devices send data to cloud platforms (like Firebase, AWS, Thingspeak).
  • You can access your data anytime from anywhere.

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1. Complete Design of Embedded Systems

  • Involves all steps to build a working embedded product.
  • Key stages:
    • Requirement Analysis – what the system should do
    • Hardware Design – selecting microcontroller, sensors, power supply
    • Software Design – writing code (in C, Python, etc.)
    • Interfacing – connecting hardware parts
    • Testing and Debugging – checking if everything works

2. Development of IoT Applications

  • Building real-world solutions using IoT devices.
  • Steps include:
    • Selecting hardware (Arduino, Raspberry Pi)
    • Connecting sensors/actuators
    • Writing code to collect and send data
    • Using protocols (like MQTT, HTTP)
    • Storing or displaying data on the cloud or mobile app

3. Home Automation

  • Controlling home devices automatically or remotely using IoT.
  • Examples:
    • Smart lights and fans
    • Voice-controlled appliances (Alexa/Google)
    • Security cameras and smart locks

4. Smart Agriculture

  • Using sensors and IoT to improve farming.
  • Examples:
    • Soil moisture sensors for watering plants
    • Weather monitoring systems
    • Crop health monitoring using drones or sensors

5. Smart Cities

  • Making urban infrastructure intelligent and efficient.
  • Examples:
    • Smart traffic control systems
    • Automatic street lighting
    • Waste management using IoT bins
    • Pollution and noise monitoring

6. Smart Healthcare

  • Using IoT in medical field for better monitoring and treatment.
  • Examples:
    • Wearable health trackers (heart rate, BP)
    • Remote patient monitoring systems
    • Emergency alert systems (fall detection for elderly)

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