Arduino Uno R3

The classic ATmega328P 8-bit microcontroller board, a popular beginner prototyping platform with 14 digital and 6 analog I/O pins.

₹799 + 18% GST

SKU: BOTBIT-DEV-01 · Best for: Learning electronics and C/C++ embedded programming in school, college and self-study

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Overview

About Arduino Uno R3.

The Arduino Uno R3 is the classic, board that launched the modern maker movement and remains the single most popular microcontroller board for learning electronics and embedded programming. Built around the 8-bit ATmega328P running at 16 MHz, it exposes 14 digital I/O pins (6 with PWM) and 6 analog inputs on a rugged, breadboard-friendly through-hole layout with the familiar Arduino shield header footprint.

It is popular in India because it is the reference board that virtually every tutorial, textbook, YouTube course and college lab is written around. The huge global community means almost any sensor, motor driver or shield you buy will already have example code and a wiring diagram tested on an Uno. The ATmega328P sits in a removable DIP socket, so if you accidentally destroy the chip you can replace just the microcontroller rather than the whole board.

For a beginner, hobbyist, student or anyone building a first prototype, the Uno R3 is the safest, most forgiving choice. It runs at 5V logic, tolerates wiring mistakes better than 3.3V boards, and is powered and programmed over a single USB-B cable.

Key features

Why it stands out.

ATmega328P 8-bit AVR microcontroller running at 16 MHz with a 5V logic level

14 digital I/O pins (of which 6 support PWM output) plus 6 analog input pins

32 KB Flash program memory (0.5 KB used by bootloader), 2 KB SRAM and 1 KB EEPROM

USB-B port for power and programming, plus a barrel jack for 7-12V external supply

ATmega328P housed in a removable DIP socket so the MCU can be swapped if damaged

Standard Arduino shield header layout compatible with thousands of add-on shields

Specifications

Selection facts.

Microcontroller	Microchip ATmega328P (8-bit AVR)
Clock Speed	16 MHz
Operating Voltage	5V
Recommended Input Voltage	7-12V (via barrel jack / VIN)
Digital I/O Pins	14 (6 provide PWM output)
Analog Input Pins	6
DC Current per I/O Pin	20 mA (40 mA absolute max)
Flash / SRAM / EEPROM	32 KB / 2 KB / 1 KB
USB Connector	USB Type-B
Board Dimensions	68.6 x 53.4 mm

Applications

Where it is used.

Learning electronics and C/C++ embedded programming in school, college and self-study
Reading sensors (temperature, ultrasonic, light, motion) and logging or displaying data
Driving LEDs, relays, servos and DC/stepper motors for basic robotics and automation
Building home-automation and hobby projects controlled by buttons, IR remotes or LCDs
Prototyping with plug-in shields such as motor drivers, Ethernet, GPS and LCD keypad shields
College mini-projects, science exhibitions and engineering lab assignments

Buying guide

How to choose.

The Uno R3 is the right board for anyone starting out, following a beginner course, or prototyping a project where 5V logic and rock-solid tutorial support matter more than speed or connectivity. If you have never used a microcontroller before, start here.

Choose the Uno R3 over the Nano when you want the shield header and a sturdy full-size board, and over the Mega when your project needs fewer than about 20 I/O pins. If you specifically need built-in WiFi or Bluetooth or a faster 32-bit core, look at the Uno R4 WiFi instead; if you need a compact breadboard footprint, consider the Nano.

Pair it with a solderless breadboard, a set of male-to-male jumper wires, a starter component kit (LEDs, resistors, buttons, a potentiometer) and a USB-B cable. A basic multimeter is a very useful companion for debugging.

FAQ

Common questions.

Which software and language do I use to program the Uno R3?

The free Arduino IDE (available for Windows, macOS and Linux). You write in C/C++ using the Arduino libraries, select 'Arduino Uno' as the board, choose the correct COM port and click Upload. No external programmer is needed because the board has a USB bootloader.

What cable does it use and is it included?

It uses a standard USB Type-B cable (the same square connector as many printers). Whether a cable is included depends on the seller's packaging, so check the listing; the cable is inexpensive and widely available in India if you need to add one.

Can I connect 3.3V sensors and modules to the Uno?

The Uno runs at 5V logic. Many 5V-tolerant modules work directly, but sending a raw 5V signal into a 3.3V-only device (for example some SD-card or ESP modules) can damage it. Use a logic-level shifter or a resistor divider on those lines to be safe.

How many devices can I power from the board's 5V pin?

Each I/O pin is rated for 20 mA and the on-board regulator has limited headroom, so it comfortably drives LEDs and small sensors. For servos, motors or LED strips, use a separate external power supply and share a common ground with the Uno.

Is this a genuine Arduino or a compatible clone?

Both genuine Arduino-branded boards and pin-compatible clones are sold in India. This listing is for the Arduino Uno R3; check the product title and brand on the page. Either works with the same code and shields, but genuine boards support the project financially and use higher-grade components.

What is the difference between the Uno R3 and the newer Uno R4?

The R3 uses the 8-bit ATmega328P at 16 MHz with 32 KB Flash. The R4 uses a faster 32-bit Renesas Cortex-M4 core, has far more memory, adds a 12x8 LED matrix, and the WiFi variant includes WiFi and Bluetooth. The R3 remains the cheaper, simpler, best-documented choice for learning.