SparkFun
Arduino Uno - R3
The Arduino Uno R3 is the most popular Arduino board and an ideal starting point for learning electronics and programming. Built around the ATmega328 microco...
The Arduino Uno R3 is the most popular Arduino board and an ideal starting point for learning electronics and programming. Built around the ATmega328 microcontroller, it offers a robust platform for prototyping, interactive projects, and connecting to sensors, actuators, and other hardware.
The R3 revision features an ATmega16U2 USB controller (replacing the earlier 8U2/FTDI), enabling faster transfer rates, more memory, and native USB device emulation — allowing the board to appear as a keyboard, mouse, joystick, or other HID device. Additional SDA/SCL pins and an IOREF pin improve shield compatibility.
Key Features
- ATmega328 Microcontroller – 32KB flash memory, 2KB SRAM, 1KB EEPROM
- 14 Digital I/O Pins – 6 of which provide PWM output
- 6 Analogue Inputs – For reading sensors and variable signals
- 16 MHz Clock Speed – Reliable performance for most projects
- ATmega16U2 USB Controller – Faster uploads and native USB HID support
- Input Voltage – 7–12V recommended (6–20V limits)
- SDA/SCL Pins – Dedicated I2C header pins alongside AREF
- IOREF Pin – Allows shields to automatically adapt to board voltage
- No Drivers Required – Plug-and-play on Linux and macOS; Windows drivers included with the Arduino IDE
Ideal For
- Beginners learning electronics and programming
- Prototyping interactive projects and IoT devices
- Robotics, home automation, and sensor-based applications
- Educational use in schools and universities
Package Contents
- 1× Arduino Uno R3
Resources
Jargon buster
Plain-language definitions for the technical terms used above.
- EEPROM
- A type of non-volatile memory that keeps stored data even when power is turned off. In a sensor module, it can be used to store settings or calibration data so they do not need to be re-entered every time.
- Flash memory
- Non-volatile memory that keeps stored data even when power is removed. In this sensor, it matters because enrolled fingerprint templates can remain saved after the project is turned off.
- HID
- Human Interface Device is a USB device class used for keyboards, mice, gamepads and similar controls. If a board supports HID over USB, it can act like an input device to a computer without needing a custom driver.
- I2C
- I2C is a two-wire communication bus used by many sensors and small modules. It matters because several I2C devices can share the same two wires, but each device needs a compatible address and your controller must support I2C.
- IDE
- Short for Integrated Development Environment, a program used to write, run and manage code. It matters because some learners prefer a traditional coding workspace instead of a guided notebook-style lesson.
- IoT
- Short for Internet of Things, meaning physical devices that connect to networks or the internet to send data or be controlled remotely. It matters if you want projects such as connected sensors, remote controls or classroom data-logging activities.
- microcontroller
- A microcontroller is a small computer on a chip that runs your program and controls connected inputs and outputs. For this product, it is the part that reads buttons and sensors, drives the display and speaker, and communicates over Bluetooth.
- native USB
- Native USB means the microcontroller itself handles USB communication, rather than using a separate USB-to-serial chip. This matters for programming, debugging, and projects that need the board to act directly as a USB device.
- PWM
- Pulse Width Modulation is a way for a digital pin to simulate variable output power by switching on and off very quickly. It matters for controlling things like LED brightness, motor speed, or servo-style signals from a microcontroller pin.
- SDA/SCL
- SDA and SCL are the two signal lines used by an I2C bus: data and clock. Seeing these names helps you identify the correct connections when wiring I2C devices, even though Qwiic cables usually hide that wiring for you.
- Shield
- An add-on board that plugs into a main controller board to give it extra features such as sensing, motor control or communication. Knowing a product supports shields helps you judge whether it can connect neatly into an existing maker-board setup.
- SRAM
- Fast temporary memory used by a processor while a program is running. More SRAM helps with projects that handle larger data buffers, networking, displays, or more complex code.
Find this product in
Brands
Arduino Uno R3 Schematic
Schematic · 81.4 KB · Click any page to view full size
Supplier page — sparkfun.com
Supplier Description · 631.5 KB · Click any page to view full size
Resources & Downloads
Guides, code examples, and more
Related Tutorials
Free guides on learn.littlebird.com.au