Arduino Uno is an open-source microcontroller board based on the ATmega328P microcontroller, designed for embedded and IoT applications.

It provides a simple hardware and software platform for reading inputs (like sensors) and controlling outputs (like LEDs, motors, and relays) using digital and analog pins.

  • Main Components of Architecture
    3.1 Microcontroller (ATmega328P)
    3.2 Power Supply Unit
    3.3 Crystal Oscillator (16 MHz)
    3.4 Digital I/O Pins (0–13)
    3.5 Analog Input Pins (A0–A5)
    3.6 Reset Button
    3.7 USB Interface (ATmega16U2)
    3.8 Power Pins (VIN, 5V, 3.3V, GND, AREF)
    3.9 ICSP Header (SPI Programming)
    3.10 LED Indicators (Power, TX/RX, Pin 13)

    • Working Principle

    • Key Features / Specifications

    • Applications of Arduino Uno

    Arduino Uno — Architecture & Overview

    Microcontroller (ATmega328P)

    • 8-bit AVR RISC MCU @ 16 MHz

    • Memory: 32 KB Flash, 2 KB SRAM, 1 KB EEPROM

    • Handles all processing & control tasks

    Power Supply Unit

    • Powered via USB or 7–20 V external adapter

    • Voltage Regulator provides stable 5 V output

    Crystal Oscillator

    • 16 MHz quartz crystal ensures accurate timing

    Digital I/O Pins (0–13)

    • Configurable as Input/Output via pinMode()

    • Pins 0–1 → RX/TX (Serial)

    • Pins 3, 5, 6, 9, 10, 11 → PWM output

    Analog Input Pins (A0–A5)

    • Reads 0–5 V analog signals

    • Connected to 10-bit ADC in ATmega328P

    Reset Button

    • Restarts program execution in microcontroller

    USB Interface

    • Used for programming & serial communication

    • ATmega16U2/8U2 acts as USB-to-Serial converter

    Power Pins

    • VIN: External input voltage

    • 5V / 3.3V: Regulated outputs

    • GND: Common ground

    • AREF: Analog reference voltage

    ICSP Header

    • Used for SPI programming of microcontroller

    LED Indicators

    • ON LED → Power status

    • TX/RX LEDs → Data communication

    • Pin 13 LED → Testing indicator

    Working Principle

    • Bootloader enables USB code upload

    • MCU executes program from Flash memory

    • I/O pins handle sensors & actuators

    • Supports UART, SPI, I²C communication

    Key Features

    • MCU: ATmega328P

    • 5 V operation, 7–12 V input recommended

    • 14 Digital I/O (6 PWM), 6 Analog inputs

    • 16 MHz clock, 32 KB Flash, 2 KB SRAM, 1 KB EEPROM

    • Supports USB programming, UART/SPI/I²C

    Advantages

    • Easy programming via Arduino IDE (C/C++)

    • Low cost, open-source, beginner-friendly

    • Supports sensors, shields, actuators

    • Large community & library support

    Disadvantages

    • Limited 8-bit, 16 MHz performance

    • No built-in Wi-Fi/Bluetooth

    • Small memory capacity

    • Not fit for multitasking

    Applications

    • IoT automation

    • Smart agriculture

    • Robotics

    • Sensor data systems

    • Wearables

    • Medical devices