What is Arduino UNO

What is Arduino UNO?

For learning electronics and programming, the Arduino UNO board is the ideal choice. The UNO is the most sturdy board you may start experimenting with if this is your first time tinkering with the platform. Among the entire line of Arduino boards, the UNO is the most popular and well-documented. It consists of two components—hardware and software—that work together as a system to create microcontroller projects quickly. One of the drawbacks of Arduino is that its foundation is the Atmel AVR microcontroller, which is buried beneath the surface and does not need to be known.


The Italian word "uno," which means "one," was chosen to signify the launch of the Arduino Software. The Uno board is the first in a line of USB-based Arduino boards. It, along with version 1.0 of the Arduino IDE, served as the prototype for further releases of Arduino. The bootloader that is preprogrammed into the board's ATmega328 enables the addition of fresh code without the need for an external hardware programmer. The Uno varies from all earlier boards in that it does not employ the FTDI USB-to-serial driver chip, even though it uses the original STK500 protocol. In its place, a USB-to-serial converter built using the Atmega16U2 (or Atmega8U2 up to version R2) is used.Arduino uno board

Fig.1. Arduino UNO board

The Arduino Uno is an open-source microcontroller board created by arduino.cc and was first made available in 2010. The board is furnished with sets of digital and analog input/output (I/O) pins that may be interfaced with various expansion boards (shields) and other circuits. The board has 14 digital I/O pins, six of which are capable of PWM output, and six analog I/O pins. It resembles the Arduino Nano and Leonardo in certain ways. It accepts voltages between 7 and 20 volts, but it can also be powered by an external 9-volt battery or by a USB cable. The hardware reference design is made accessible on the Arduino website and is given under a Creative Commons Attribution Share-Alike 2.5 license. There are additional layout and production files available for various hardware versions. 

Feature of Arduino UNO board

  1. It has an ATMega328 microcontroller.
  2. Uno's size is smaller than Mega's since its dimensions are 2.7 inches by 2.1 inches.
  3. Due to its reduced size, it is a viable option for applications with limited space.
  4. It offers 32 kB of Flash memory.
  5. The Arduino Uno's EEPROM is 1 kB.
  6. The Arduino Uno's SRAM is 2 kB.
  7. This is what engineers choose when a project just requires a small number of GPIO pins.
  8. Highly software compatible is Arduino Uno.
  9. In Uno, there are 14 digital I/O pins.
  10. In Uno, there are 6 digital I/O pins with PWM capabilities.
  11. Six analogue pins are accessible on the board

Arduino UNO Pin DiagramArduino UNO pin diagram

Fig.2. Arduino UNO pin diagram

General Pin Description of UNO

  • Vin: The Arduino/Genuino board's input voltage when using an external power source (as opposed to 5 volts from the USB connection or other regulated power source). This pin can be used to access voltage that has been supplied via the power jack or to feed voltage to it.
  • 5V or 3.3V: The regulator on the board outputs a controlled 5V or 3.3V through this pin. The board's VIN pin, the USB connector (5V), or the DC power jack (7 to 20V) can all be used to supply power to it (7-20V).
  • IOREF: The microcontroller uses this pin on the Arduino/Genuino board as its voltage reference. The IOREF pin voltage can be read by a properly constructed shield, which can then choose the proper power supply or enable voltage translators on the outputs to operate with 5V or 3.3V.
  • RESET: Shields that block the reset button on the board are frequently added with this feature.

Hardware Components:Components present in the Arduino UNO board

Fig.3. Components present in the Arduino UNO board

  • Microcontroller ATmega328: This member of the Atmel family is a single-chip microcontroller. Its processor code is 8 bits in size. In addition to Memory (SRAM, EEPROM, and Flash), Analog to Digital Converter, SPI serial ports, I/O lines, registers, timer, external and internal interrupts, and oscillator, it also includes an oscillator.
  • The In-Circuit Serial Programming (ICSP) pin enables programming with the Arduino board's firmware.
  • Power LED Indicator: An ON LED indicates that power is on. The LED won't light up if the power is turned off.
  • Digital I/O pins: Digital pins can be HIGH or LOW in value. Digital pins are those with the numbers D0 through D13.
  • TX and RX  LEDs signify a successful data transfer.
  • The Arduino UNO board receives a reference voltage from the external power source via the Analog Reference (AREF) pin.
  • Reset button: It is used to give the connection a Reset button.
  • The board can connect to the computer through USB. It is necessary for the Arduino UNO board's programming.
  • Crystal Oscillator: The Arduino UNO is a robust board due to the 16MHz crystal oscillator.
  • Using a voltage regulator, the input voltage is changed to 5V.
  • GND — Ground pins The ground pin functions as a pin that is not powered.

How to use the Arduino UNO

As we mentioned, it works by using the software. Generally, all are preferred the Arduino Integrated Development Environment software, The screenshot of the software were pasted below,

Fig.4. Arduino IDE

Basically, it consists of two sections called void functions, first section is the void setup() function you will initialize the pin and other things that you want and it runs only once. Secondly, the void loop() function that you can run your code multiple times.

Fig.5. Verify button in Arduino IDE

After the code is written you can verify your code by clicking the verify button shown in fig. 5

Fig.6. Select the board in Arduino UNO

Fig.7. Select the Port in Arduino UNO

Once the code is verified, select the board and port shown in the above fig 6 and fig 7 respectively. After that upload the code to your Arduino UNO Board.

Applications of Arduino UNO:

The Arduino boards can be used for standalone projects as well as for interfacing with different sensors and actuators. The following uses use the Arduino UNO board.

  1. Weighing Machines
  2. Traffic Light Count Down Timer
  3. Parking Lot Counter
  4. Embedded systems
  5. Home Automation
  6. Industrial Automation
  7. Medical Instrument
  8. Emergency Light for Railways

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