Arduino Nano V3

A breadboard-friendly ATmega328P board that packs an Uno's capability into a compact 30-pin format.

What is the Arduino Nano V3?

The Arduino Nano V3 is a compact microcontroller board built around the ATmega328P, the same 8-bit AVR chip used in the Arduino Uno. It runs at 16 MHz with 5V logic and carries 32 KB of flash, 2 KB of SRAM, and 1 KB of EEPROM. The board measures just 43.2 x 17.8 mm and presents its pins as two rows of male headers, so it seats directly across the center channel of a standard breadboard for solderless prototyping.

Despite its size, the Nano exposes 22 general-purpose I/O pins, 8 analog inputs (A0 through A7, two more channels than the Uno) at 10-bit resolution, and 6 PWM outputs. Hardware UART, I2C, and SPI peripherals are all available on the header. An onboard FTDI FT232RL bridges USB to serial over a Mini-B connector, handling both sketch uploads and the serial monitor without any external programmer.

Because it shares the ATmega328P core, the Nano runs the same sketches, libraries, and toolchain as the Uno with no code changes. Makers reach for it when a project needs the Uno feature set in a smaller footprint: permanent breadboard or perfboard builds, small robots, wearables, and embedded sensor nodes where the Uno's larger board would not fit.

Arduino Nano V3 pin reference

Pin	Function	Type
`D12` D12 (MISO)	SPI MISO · Digital	Bidirectional (GPIO)
`D11` D11 (MOSI)	SPI MOSI · PWM · Digital	Bidirectional (GPIO)
`D10` D10 (SS)	SPI CS · PWM · Digital	Bidirectional (GPIO)
`D9` D9	PWM · Digital	Bidirectional (GPIO)
`D8` D8	Digital	Bidirectional (GPIO)
`D7` D7	Digital	Bidirectional (GPIO)
`D6` D6	PWM · Digital	Bidirectional (GPIO)
`D5` D5	PWM · Digital	Bidirectional (GPIO)
`D4` D4	Digital	Bidirectional (GPIO)
`D3` D3	PWM · Digital	Bidirectional (GPIO)
`D2` D2	Digital	Bidirectional (GPIO)
`GND_R` GND	Power	Power in
`RST_R` RST	Digital	Digital input
`D0` D0 (RX)	UART RX · Digital	Bidirectional (GPIO)
`D1` D1 (TX)	UART TX · Digital	Bidirectional (GPIO)
`D13` D13 (SCK, LED)	SPI SCK · Digital	Bidirectional (GPIO)
`3V3` 3V3	Power	Power out
`AREF` AREF	Analog	Digital input
`A0` A0	Analog ADC0 · Digital	Bidirectional (GPIO)
`A1` A1	Analog ADC1 · Digital	Bidirectional (GPIO)
`A2` A2	Analog ADC2 · Digital	Bidirectional (GPIO)
`A3` A3	Analog ADC3 · Digital	Bidirectional (GPIO)
`A4` A4 (SDA)	Analog ADC4 · I²C SDA · Digital	Bidirectional (GPIO)
`A5` A5 (SCL)	Analog ADC5 · I²C SCL · Digital	Bidirectional (GPIO)
`A6` A6	Analog ADC6	Digital input
`A7` A7	Analog ADC7	Digital input
`5V` 5V	Power	Power out
`RST_L` RST	Digital	Digital input
`GND_L` GND	Power	Power in
`VIN` VIN	Power	Power in

Specifications

Operating voltage: 5 V
Clock speed: 16 MHz
Flash: 32 KB
RAM: 2 KB
GPIO pins: 22
ADC: 8 channels · 10-bit
PWM channels: 6
Dimensions: 43.2 × 17.8 × 10 mm

Verified from the Tinkered component library · Arduino.

Circuit requirements

Logic level is 5V. Every digital and analog I/O pin operates at 5V, so 3.3V-only devices need level shifting on any line the Nano drives to avoid overdriving their inputs.
Three power paths are available: the Mini-USB port (5V), the VIN pin (accepts 7-12V through the onboard regulator), or the 5V pin used as a regulated 5V input. Do not feed power into more than one of these at once.
The 5V pin bypasses the voltage regulator. Only apply a clean, regulated 5V here. Unregulated supplies above 5V belong on VIN, never on the 5V pin.
The 3V3 output pin is derived from the FT232RL USB chip and can source only a small current (roughly 50 mA), so it is not suitable for powering hungry 3.3V modules.
A6 and A7 are analog-input only. They can be read with analogRead but cannot act as digital I/O or drive outputs.

Simulate the Arduino Nano V3 in your browser

The Arduino Nano V3 is fully simulated in Tinkered. Wire it into a circuit, write your firmware, and read real values back with no physical hardware. Test your logic before you touch a breadboard.

Open it in the simulator

Common Arduino Nano V3 mistakes

Treating A6 and A7 as digital pins

Unlike A0 through A5, the A6 and A7 pins connect only to the ADC. digitalRead, digitalWrite, and pinMode do not work on them. Use them for analog sensors, and keep any button or LED on the other pins.

Feeding raw voltage into the 5V pin

The 5V pin sits after the regulator, so applying 7-12V there bypasses regulation and can destroy the ATmega328P and connected devices. Unregulated input up to 12V must go to VIN instead.

Wrong bootloader selection in the IDE

Many Nano boards ship with the older bootloader. If uploads fail with a sync or timeout error, switch the IDE to the 'ATmega328P (Old Bootloader)' processor option before troubleshooting anything else.

Missing USB-to-serial driver

Genuine Nanos use the FTDI FT232RL, while many clones use a CH340 chip. If the board never enumerates as a serial port, install the matching FTDI or CH340 driver for your operating system.

Overloading the 3V3 pin

The 3V3 rail comes from the FTDI chip, not a dedicated regulator, and delivers only tens of milliamps. Powering a display or radio module from it can brown out the USB link and cause resets.

Arduino Nano V3 datasheet

Official Arduino Nano V3 datasheetArduino

Popular Arduino Nano V3 projects

Permanent breadboard and perfboard builds

The DIP-style pin layout lets the Nano stay soldered into a finished project, making it a natural upgrade from an Uno prototype to a compact, standalone board.

Small robots and line followers

Its light 7 g weight and full complement of PWM and digital pins drive motor controllers, IR sensors, and servos in tabletop robots where board size matters.

Environmental sensor nodes

Hardware I2C on A4 (SDA) and A5 (SCL) plus 8 analog inputs make it easy to read temperature, humidity, and light sensors and log the data over the USB serial link.

Wearable and portable gadgets

The small footprint fits inside enclosures too tight for an Uno, powering LED effects, counters, and pocket instruments from a battery on VIN.

Addressable LED controllers

A single PWM-capable data pin drives strips of individually addressable LEDs, with the extra analog inputs free for potentiometers or sound sensors that set the animation.

Home automation relay controllers

Digital outputs switch relay modules for lights and appliances, while the compact board tucks neatly into a project box alongside the relays.

Build with the Arduino Nano V3.

Drop the Arduino Nano V3 into a circuit, write firmware, and simulate it in your browser, then deploy to real hardware. All in one editable Tinkered project.

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