Smallest Arduino Boards for your Mini Arduino Projects

Looking for small Arduino boards for your mini Arduino projects? Want to create a wearable device with an Arduino? Arduino board too big? Tiny Arduino board not powerful enough and not functional due to its size?

If all your answers to the above answers are all yes, this guide will be just for you! We have compiled various smallest Arduino boards out there into a list for you to pick from which you can use to integrate into nearly any mini Arduino project from robots to wearables.

We will also include a few mini Arduino projects to show you what the tiny Arduino boards can do as well!

Without further ado, let us look at the various tiny boards which you can use to minimize your Arduino projects with:

Seeeduino Nano

45mm x 18mm

Coming in first, we have the Seeeduino Nano which is a compact board similar to the Seeeduino V4.2/Arduino UNO, and it is fully compatible with Arduino Nano on pinout and sizes . Despite not being the smallest, we feel that this belongs in this list due to how widely used the Arduino Nano is with a big community and support for debugging which we highly recommend for beginners just starting out. In addition, if you have a code from your previous Uno project, you can easily move it to the Nano!

Operating at 16 MHz with 32KB of program memory, 1KB of EEPROM, 2KB of RAM, 14 digital I/O, 6 analog inputs and both 5V and 3.3V rails, the Seeeduino Nano is packed with peripherals for its size It has more or less the same functionality of the Arduino Duemilanove, but in a different package. Furthermore, it has a Grove I2C connector where with the help Grove system, you can play with hundreds of sensors and actuators simply by plugging. It has also a Type-C USB which is symmetrical and reversible instead of a mini USB.

Why not use an Arduino Nano?

Well, first of all, it would be the price. At only $6.90 you can get yourself a Seeeduino Nano instead of spending $22 for an Arduino Nano. In addition, you get more peripherals on the Seeeduino board as well. You basically get more for less!

Not enough peripherals?

If you feel like the Seeeduino still does not have enough peripherals for your mini project, you can check out our Grove Shield for Arduino Nano:

With 3 Grove digital connectors, 3 Grove analog connectors, 1 Grove I2C connector, and 1 Grove UART connector, these Grove interfaces are definitely more than enough for your projects. If you still need more, you can also use our Grove – I2C Hub

Curious what the Seeeduino Nano can be used for? Check out 20 Best Arduino Nano Projects that you must try now to see what the Nano can do!

Tech Specs:

SpecsSeeeduino Nano
Operating Voltage5V
Digital I/O Pins22
PWM Enable Pins6
Analog I/O pins8
Flash Memory32KB
Clock Speed16 MHz
Size45 mm x 18 mm

Arduino MKR1000

61.5mm x 25mm

Do you need a powerful board with Wifi capabilities? Have minimal experience in networking? If your answers are yes, the Arduino MKR1000 is for you!

Arduino MKR1000 has been designed to offer a practical and cost-effective solution for makers seeking to add Wi-Fi connectivity to their projects with minimal previous experience in networking. It is based on the Atmel ATSAMW25 SoC (System on Chip), which is part of the SmartConnect family of Atmel Wireless devices, specifically designed for IoT projects and devices.

The ATSAMW25 is composed of three main blocks:

  • SAMD21 Cortex-M0+ 32bit low power ARM MCU
  • WINC1500 low power 2.4GHz IEEE® 802.11 b/g/n Wi-Fi
  • ECC508 CryptoAuthentication

The ATSAMW25 includes also a single 1×1 stream PCB Antenna.

The design includes a Li-Po charging circuit that allows the Arduino/Genuino MKR1000 to run on battery power or external 5V, charging the Li-Po battery while running on external power. Switching from one source to the other is done automatically.

It features a 32-bit computational power similar to the Zero board with the usual rich set of I/O interfaces, low power Wi-Fi with a Cryptochip for secure communication. Best of all, it is compatible with Arduino IDE to provide you with the ease of use of the Arduino Software (IDE) for code development and programming.

All these features make this board the preferred choice for the emerging IoT battery-powered projects in a compact form factor. The USB port can be used to supply power (5V) to the board and it is able to run with or without the Li-Po battery connected. It has limited power consumption as well!

Tech Specs:

Specs Arduino MKR1000
MicrocontrollerSAMD21 Cortex-M0+ 32bit low power ARM MCU
Operating Voltage3.3V
Digital I/O Pins8
PWM Enable Pins12
Analog I/O pins8
Flash Memory256KB
Clock Speed48 MHz
Size61.5mm x 25mm

Arduino Pro Mini

33mm x 18mm

When it comes to mini boards, of course the Arduino Pro Mini has to be inside the list.

They are basically the Arduino Pro but packed in a much smaller footprint. Connectors and USB-to-serial-converting circuitry are all removed leaving the Arduino Pro Mini with the bare minimum. In the Pro Mini, more pins are broken out from the Pro.

At such a small size, the Pro Mini definitely aren’t shield-compatible but they are breadboard-compatible with soldered on male headers. Its size also allows them to be embedded into your projects easily. When programming the Pro Mini, you will need more than just a USB cable. You will need an external board to convert USB from your desktop to serial where the Arduino can process using something like a USB CP2102 Serial Converter.

The Pro Mini comes in two varieties 5V/16MHz and 3.3V/8MHz where the 5V runs at the same voltage and speed as the Arduino Nano and Micro. With the 3V board, speed is slower and consumes lesser power which makes your board easy to power with batteries.


SpecsArduino Pro Mini
Operating Voltage5V / 3.3V
Digital I/O Pins14
PWM Enabled Pins6
Analog I/O pins6
Flash Memory32 KB (2KB used by Bootloader)
Clock Speed8 / 16 MHz
Size33 mm x 18 mm

Arduino MKR VIDOR 4000

83mm x 25mm

Even though this board is definitely not one of the smallest Arduino board, it has unique features which you do not normally find on an Arduino board. Besides, it comes in a reasonable small package as well for your tiny projects!

If you are Looking for a board for a very specific use that Arduino doesn’t make, or maybe you want a more complex central board, optimized for your particular needs that will interface with all other Arduino boards and devices? The MKR VIDOR 4000 is highly configurable and powerful, and it can perform high-speed digital audio and video processing.

With the MKR VIDOR 4000, you can configure it the way you want; you can essentially create your own controller board. It comes loaded with hardware and potential: an 8 MB SRAM; a 2 MB QSPI Flash chip — 1 MB allocated for user applications; a Micro HDMI connector; a MIPI camera connector; and Wifi & BLE powered by U-BLOX NINA W10 Series. It also includes the classic MKR interface on which all pins are driven both by SAMD21 and FPGA. Plus, it has a Mini PCI Express connector with up to 25 user-programmable pins.

The FPGA contains 16K Logic Elements, 504 KB of embedded RAM, and 56 18×18 bit HW multipliers for high-speed DSP. Each pin can toggle at over 150 MHz and can be configured for functions such as UARTs, (Q)SPI, high resolution/high-frequency PWM, quadrature encoder, I2C, I2S, Sigma Delta DAC, etc.

The on-board FPGA can be also used for high-speed DSP operations for audio and video processing. This board also features a Microchip SAMD21. Communication between FPGA and the SAMD21 is seamless.

Clueless about what FPGA is? You can check out our guide on FPGA and FPGA Dev Boards – What is it and What are they used for.

If you want an FPGA Arduino board yet you are space-constrained, this board will definitely be for you.


Specs Arduino MKR VIDOR 4000
FPGAIntel® Cyclone® 10CL016 (datasheet)
Operating Voltage3.3V
Digital I/O Pins22 headers + 25 Mini PCI Express
PWM Enabled PinsAll Pins
Analog I/O pins
Flash Memory2MB
Clock Speed48 MHz – Up to 200 MHz
Size 83mm x 25mm

Arduino Micro

48mm x 18mm

Up next, we have the Arduino Micro which is slightly bigger than the Nano and has been similarly designed to fit on a solderless breadboard. However, it is powered by the ATmega32U4 which is different from the Nano. In terms of size, it is slightly bigger than the Arduino Nano at 48mm x 18mm.

Compared to the Nano, the Micro comes with more peripherals for your project needs. With 20 digital I/O pins, 12 analog inputs, and 7 PWM enabled pins. In addition, with a native USB, you can use it as a mouse, keyboard, etc easily. However, the Micro bootloader can only be programmed with USB that requires a special driver. With Linux, only a few selective versions have the needed driver.

In addition, unlike the Pro Mini, the Micro doesn’t require an external board to upload a sketch just let the 32U4 takes care of everything!

Basically, if you guys know the Arduino Leonardo, the Arduino Micro is a shrunk-down version of it and the Arduino Nano is a shrunk-down version of the Arduino Uno. The micro is the smallest board of the family of ATmega32U4 Arduino.


SpecsArduino Micro
Operating Voltage5V
Digital I/O Pins20
PWM Enabled Pins7
Analog I/O pins12
Flash Memory32 KB (4KB used by bootloader)
Clock Speed16 MHz
Size48 mm x 18 mm

Seeeduino XIAO

20mm x 17.5mm

Lastly, we have the smallest Arduino of this list! The Seeeduino XIAO is the smallest Arduino compatible board from SeeedStudio’s Seeduino family and is one of the smallest Arduino boards out there.

Sometimes when boards get too small, they lose its functionalities and capabilities but not for this Arduino board! The Seeeduino XIAO is an Arduino microcontroller that is embedded with the SAMD21 microchip with rich interfaces as well allowing it to be capable of being a tiny Dev. Board as well.

Apart from the strong CPU, Seeeduino XIAO is excellent in many other functions. Despite being this small size, it has 14 GPIO PINs, which can be used for 11 analog PINs, 11 digital PINs, 1 I2C interface, 1 UART interface, and 1 SPI interface. Some PINs have various functions, A1/D1 to A10/D10 Pins have PWM functions and Pin A0/D0 has a function of DAC which means you can get true analog signals not PWM signals when you define it as an analog pin, that’s why 14 GPIO PINs can realize more I/O PINs and interfaces.

The board is also breadboard compatible which is very rare for a small board like this!

The Seeeduino XIAO supports the USB Type-C interface which can supply power and download code. In addition, there are power pads at the back of the XIAO which support battery and makes designing wearable devices easy and simple. Other than the power LED, we also added a user LED on board for better coding experience.

Usually a Dev. Board as small as this size will use the chip’s inner crystal oscillator for time fixing, in order to make the clock more accurate, Seeeduino XIAO layouts an extra 32.768KHz to make the clock more stable.

And of course, the Seeeduino XIAO is perfectly compatible with Arduino IDE which allows you to easily develop small projects with the help of the large and comprehensive Arduino library.

The best news is, you can get all features packed on a tiny board this just for only $4.90 together with two headers and 4 different stickers to place on top of the metal shield! Wow!


SpecsSeeeduino XIAO
Operating Voltage3.3V
Digital I/O Pins11
PWM Enabled Pins10
Analog I/O pins11
Flash Memory256 KB
Clock Speed48 MHz
Size23.5mm x 17.5mm

Arduino Based Mini Projects

Do not know what you can do with these tiny Arduino boards? Fret not as here are some mini projects to get you started!

Arduino Nano Wearable Heart Rate Monitor

Ref: Ultimate Robotics

Smart watches are all pretty expensive currently so why not make it yourself with an Arduino Nano! With its small size, they are very easy to integrate into wearable projects like this one!

What do you need?

Interested? You can find the full tutorial by Dmitry Dziuba on Arduino Project Hub!

Home Automation Project

Ref: Andres Santos

With these small Arduino boards, they are very easy to embed into any systems like this home automation example. With this project, you can now control home appliances with the help of Siri and Apple HomeKit.

What do you need?

Interested? You can find the full tutorial by Andres Santos on Arduino Project Hub!

Arduino Doorbell

With this project, you can connect your door to the cloud and open it from everywhere. In addition, it will also play a song when the door opens!

What do you need?

Interested? You can find the find the full tutorial by Arduino_Genuino on Arduino Project Hub

Pocket-Sized Touch Keyboard

With the small size of these boards, you can make various small Arduino based device or wearable! For this project, we will be making a device that can perform different keyboard operations through capacitive touch sensing.

What do you need?

  • Arduino Micro & Genuino Micro
  • Jumper Wires (Generic)
  • Resistor 1M Ohm
  • Soldering Iron (Generic)

Interested? You can check out the full tutorial by Amal Mathew on Arduino Project Hub.


What do you think of these smallest Arduino boards? What would you use them for? Which one is your favourite?

Let us know in the comments down below!

Interested in more Arduino boards? Check out all our Arduino boards and Compatible boards!

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