Over the years, Arduino has been chosen as the favorite platform by makers and pros of any level, thanks to a prolific community and constant support from the developers. But with the growing demand for cheaper dev boards, the offer has adapted, too. Today the microcontroller market can feel chaotic, with too many options to choose from.
The advantage is that it’s not hard to find a solution that integrates a powerful chip in a tiny package – and all of this without sacrificing I/O, sensors, or features.
We’ve put together a list of the tiniest, most feature-packed boards (both from the Arduino family and other brands). But before we get to it, let’s take a closer look at how we’ve sourced them.
Considerations
In putting together this list, we landed on a few considerations to narrow down the options. All the boards that follow meet a few criteria:
- IDE support: The Arduino IDE must support the board natively or with a plug-in. This allows makers of all levels to program in a beginner-friendly, well-documented, and extremely versatile environment.
- A tiny package: Of course, the form factor must be as small as possible. Everything on this list is smaller than an Arduino Uno/Leonardo, closer to the form factor of an Arduino Nano/Micro.
- Uniqueness: Any third-party, Arduino-compatible models included have distinctive features and aren’t exact copies of the original boards. For this reason, even when they’re slightly cheaper, we’ve excluded direct clones and no-name boards.
- Variety: We’ve included boards that should appeal to a range of makers. Every project is unique and might require different hardware to be completed successfully. We’ve also got boards that suit professional applications, and more niche markets are covered, too.
Before we get started, just note that due to the current chip shortage, prices indicated throughout the article may vary drastically. We’ll be keeping an eye on the market and will be sure to update when prices stabilize. With that in mind, let’s get to the list!
Arduino Family
We’re starting with the classics, the original Arduino boards. These will naturally have the broadest support and the most exhaustive first-party documentation.
Micro
The Arduino Micro is the spiritual successor to the Arduino Leonardo, alive again in a much smaller body. One of the key features of this board is the built-in USB communication, eliminating the need for a separate USB chip. The advantage of using a single chip for every operation is an increase in flexibility while communicating with a computer. As the board appears as a virtual serial port to your computer (e.g. for programming), it can also behave like a keyboard, or a mouse, or a generic peripheral.
Since having a USB port isn’t an exclusive feature anymore, the Arduino Micro has a couple of aces up its sleeve. It’s a great starting point for newcomers, it doesn’t require a breadboard, and it has many projects already developed by the community. You can check out our list of great Arduino projects to inspire your next endeavor.
- Specs: 16-MHz ATmega32U4, 28-kB flash, 2.5-kB SRAM, 1-kB EEPROM
- Dimensions and weight: 48 x 18 mm, 13 g
- Features: 20 digital I/O pins, with PWM and analog input support
- Price: ~$25
Nano
The Nano board family offers a few options, with different onboard sensors and connectivity, as well as CPUs and memory. As the name suggests, they pack a lot of potential in a tiny form factor. In fact, they were designed with IoT, wearables, and robotics in mind. This doesn’t stop them from being versatile tools, of course. If you’re looking for new, cool contraptions to make, check out our list of the best Arduino Nano projects.
Arduino Nano Every
Arduino’s smallest board (and one of the cheapest), is only 45 x 18 mm. The Every is a direct replacement for the original Nano but packs a more powerful processor and twice the amount of RAM. This makes it perfect to revive and upgrade an older Nano project.
- Specs: 20-MHz ATMega4809, 48-kB Flash, 6-kB SRAM, 256-byte EEPROM
- Dimensions and weight: 45 x 18 mm, 5 g
- Features: 23 GPIO pins, supporting UART, SPI, I2C protocols
- Price: ~$14
Arduino Nano RP2040 Connect
It feels strange, almost illegal, to find a Raspberry Pi RP2040 chip on an official Arduino board. But it’s not, and this collaboration brought us the best of both worlds. The clear advantage is the ability to support both the RP2040 and Arduino ecosystems and libraries, including the Arduino IDE.
The RP2040 is the red fruit company’s first homemade microcontroller: a dual-core Arm Cortex-M0+. With plenty of on-chip RAM and a port of TensorFlow Lite, it’s ready for machine learning applications. And if all of this still wasn’t enough, it also packs a 6-axis IMU and an omnidirectional microphone. It’s the only RP2040-enabled board with onboard Wi-Fi and Bluetooth connectivity (at the time of writing).
- Specs: 133-MHz Pi RP2040, 16-MB Flash, 520-KB SRAM
- Dimensions and weight: 45 x 18 mm, 6 g
- Features: 23 GPIO pins; Wi-Fi and BT/BLE connectivity; supports SPI, UART, and I2C protocols
- Price: ~$30
MKR
The MKR lineup offers unique and exotic features that we don’t see every day. While these might not be the Swiss army knives of development boards, they’ll speed up a project in their respective field.
Arduino MKR Zero
Originally intended for music-related projects, the MKR Zero is now widely adopted for all purposes. It’s the only Arduino board that comes with an integrated SD card slot, a useful feature often overlooked. This – combined with the support for LiPo battery charging, a dedicated audio I2S bus, and the Arduino Sound Library – makes it great for wearable music devices. If you’re interested in the topic, you might want to check out our list of DIY Arduino MIDI controllers.
- Specs: 48-MHz SAMD21 Cortex-M0+, 256-kB Flash, 32-kB SRAM, no EEPROM
- Dimensions and weight: 61.5 x 25 mm, 32 g
- Features: 23 GPIO pins, LiPo charger, MicroSD slot, I2S bus
- Price: ~$30
Arduino MKR GSM 1400
The main feature of the GSM 1400 is that it’s built around the integration of the cellular GSM/3G network. When Wi-Fi, Bluetooth, or Ethernet can’t reach your project, 3G connectivity is the way to go. Not only does it cover a vast portion of the world’s surface, but a 3G SIM (alongside a pay-as-you-go plan) is pretty cheap nowadays. It could even be an SMS-only plan, communicating with your phone via text messages directly. Arduino also offers the Arduino SIM to communicate with Arduino IoT Cloud.
- Specs: 48-MHz SAMD21 Cortex-M0+, 256-kB Flash, 32-kB SRAM, no EEPROM
- Dimensions and weight: 67.64 x 25 mm, 32 g
- Features: 23 GPIO pins, Micro-SIM slot, Wi-Fi and BT/BLE, LiPo charger, external antenna connector
- Price: ~$70
Arduino MKR WiFi 1010
As the name suggests, the WiFI 1010 comes with onboard Wi-Fi, as well as Bluetooth. Like the RP2040 Connect, it fully supports the WiFiNINA library for wireless connectivity: a simplified network library that speeds up the connection process. For more advanced IoT projects, the WiFi 1010 can be integrated with online services such as Microsoft Azure and Google Firebase. You can even create your own smart home devices.
- Specs: 48-MHz SAMD21 Cortex-M0+, 256-kB Flash, 32-kB SRAM, no EEPROM
- Dimensions and weight: 61.5 x 25 mm, 32 g
- Features: 23 GPIO pins, Micro-USB, Wi-Fi and BT/BLE, LiPo charger
- Price: ~$40
Portenta H7
For years, Arduino suffered from the fact that most of their boards, albeit versatile, didn’t satisfy industry standards. Therefore, they couldn’t be used in more complex environments. But in recent times, they tackled the problem at the root, releasing an Arduino professional lineup.
The Arduino Portenta H7 is a computational workhorse, the most powerful (and expensive) on this list. It integrates a dual-core ARM CPU, with parallel operation for hardware-accelerated AI computing. It comes with a GPU that can output to an external monitor via USB Type-C, and an 8-bit bus for camera interfaces. It can run native Mbed, MicroPython/JavaScript (via an interpreter), and TensorFlow Lite. It follows the same form factor and pinout of the MKR family but adds 80-pin high-density connectors on the other side of the PCB.
Considering the increasing interest in AI computing among small makers and enthusiasts, it’s safe to say it won’t be used by professionals only. And if you want to dip your toes in IoT, take a look at the best IoT projects using Arduino.
- Specs: 480-MHz/240-MHz ARM STM32H747XI dual Cortex-M7+M4, up to 16-MB NOR Flash, up to 8-MB SDRAM
- Dimensions and weight: 66 x 25 mm, 11 g
- Features: Wi-Fi and BT, LiPo and Li-Ion charger, USB Type-C High Speed
- Price: ~$115
Nicla Family
The Nicla family, which includes the Sense ME, Vision, and Voice boards, is a recent addition to Arduino’s lineup. These tiny boards come equipped with industrial-grade sensors, making it possible to use low-power AI and machine learning for your projects. Here’s a closer look at each of the three boards.
Nicla Sense ME
The Sense ME is possibly the most well-rounded of the three boards, with ME standing for “motion” and “environment”. It has four separate Bosch sensor packages on board, including a motion sensor (IMU), magnetometer, pressure sensor, and gas sensor. It’s four sensor dev kits in one!
These industrial-grade sensors allow the Sense ME to smartly analyze its environment and motion. Add to that a powerful Arm processor, Bluetooth LE, and an integrated battery charger, and you have an incredibly capable board that can be slotted into just about any project.
Some prime use cases would be a weather station that can also detect changes in air quality, like CO2 concentration, or a robust, all-in-one sensor suite for an interactive robot.
- Specs: 64 MHz Arm Cortex M4, 512-kB Flash, 64-kB RAM
- Dimensions and weight: 22.86 x 22.86 mm, 2 g
- Features: BHI260AP IMU; BMP390 barometer; BMM150 magnetometer; BME688 gas sensor; BLE connectivity; supports SPI, I2C, and serial port for communication
- Price: ~$83
Nicla Vision
As its name suggests, the Vision is a smart camera that can be your eyes for a diverse range of projects. The board features a 2-MP color camera paired with an STM32 H7 processor. The addition of an integrated microphone, distance sensor, and 6-axis motion sensor makes this board ideal for image-based machine-learning applications, including object recognition and tracking.
The main microcontroller powering the Vision is a dual-core Arm processor, making it more adept at processing large amounts of image data. Like its siblings, it also features a battery charging circuit and Bluetooth LE. The Vision is perfect for IoT applications, especially when combined with an Arduino MKR board and the Arduino Cloud service.
One way to showcase this board’s capabilities would be to build a wildlife camera that can compare images to a data set to identify different species. Or perhaps a smart mirror that could guess your mood or know what you’re wearing? The possibilities are endless!
- Specs: STM32H747AII6 Dual Arm Cortex (1x M7 480 MHz and 1x M4 240 MHz), 2-MB Flash, 1-MB RAM
- Dimensions and weight: 22.86 x 22.86 mm, 2 g
- Features: 2-MP color camera; LSM6DOX IMU; VL53L1CBV0FY/1 distance sensor; MP34DT05 microphone; Wi-Fi and BLE connectivity; supports SPI, I2C, and serial port for communication
- Price: ~$115
Nicla Voice
The Voice offers the magic of voice recognition in a tiny package. The integrated microphone and Syntiant Neural Decision Processor allow the Voice to handle voice detection and recognition onboard, without relying on cloud processing. This makes it easier to retrofit just about any project with voice and gesture recognition functionality.
In addition, the Voice can be trained to recognize all sorts of sounds, not just words. This opens up possibilities for use in industrial applications. For example, it can be used to identify noise changes in machinery and alert the user that it’s time for maintenance before a failure occurs.
Another exciting application is echo cancellation, which can be used to protect the hearing of those working in noisy environments.
- Specs: NDP120 Neural Decision Processor, 64 MHz Arm Cortex M4, 512-kB Flash, 64-kB SRAM, 48-kB dedicated SRAM for the NDP120
- Dimensions and weight: 22.86 x 22.86 mm, 2 g
- Features: IM69D130 high performance microphone, BMI270 IMU, BMM150 magnetometer
- Price: ~$82
Alternatives
Now, we have a choice of boards that build on the original open-source design, adding unexplored features or simplifying the learning curve for newcomers.
Adafruit Trinket M0
This compact board comes with everything it needs to run: full USB host with dedicated pins, true serial, auto-switching between power sources, and more. It ships with CircuitPython already installed (a version of Python designed by Adafruit Industries). This means that when plugged into a computer, it’s recognized as a storage device.
All the programming can be done by editing the main.py file on it with a basic text editor. And it’s also supported by the Arduino IDE via an add-on for a more complex and low-level operation.
- Specs: 48-MHz ATSAMD21E18 Cortex M0+, 256-kB flash, 32-kB SRAM
- Dimensions and weight: 21 x 17.5 mm, 1.4 g
- Features: 5 GPIO pins
- Price: ~$12
Adafruit ItsyBitsy
The ItsyBitsy line of microcontroller boards from Adafruit strikes a compromise between size and capability, yet still manages to be surprisingly small. If you need more I/O pins than other Adafruit offerings (like the Trinket M0) and are willing to go to a bit larger size, these little boards may fit the bill.
ItsyBitsy M0
The Adafruit Trinket is a popular choice for good reason. However, it’s somewhat limited, with only five GPIO pins. The ItsyBitsy M0 fixes this problem with a whopping 23 GPIO pins, with its entire perimeter taken up by I/O.
If driving RGB LEDs is what you’re after, the M0 really delivers. It features a Vhigh output to feed power-hungry devices like NeoPixel LEDs, as well as a level-shifted output on pin 5 for higher logic voltage that can control long strings of LEDs with better stability.
- Specs: ATSAMD21G18 Cortex M0+, 256-kB Flash, 32-kB RAM
- Dimensions and weight: 35.9 x 17.8 mm, 2.4 g
- Features: 23 GPIO pins, 2-MB SPI Flash, native USB support, CircuitPython enabled
- Price: ~$12
ItsyBitsy M4 Express
The ItsyBitsy M4 Express has an identical footprint, layout, and feature set as the M0 but with even more horsepower, thanks to its ATSAMD51 Cortex M4 processor. It runs at more than twice the frequency as the M0, at 120 MHz compared to 48 MHz.
The M4 also has double the Flash and six times the RAM, at 192 kB! So, if the specs of the already capable M0 aren’t quite enough for your project, the M4 Express should have you covered.
- Specs: ATSAMD51 Cortex M4, 512-kB Flash, 192-kB RAM
- Dimensions and weight: 35.9 x 17.8 mm, 2.4 g
- Features: 23 GPIO pins, 2-MB SPI Flash, native USB support, CircuitPython enabled
- Price: ~$15
Seeeduino
The only thing preventing the Seeduino XIAO dev boards from having an under 0-g weight is the fact that physics doesn’t work this way. We definitely suggest getting them with pre-soldered pins, because they’re really, really tiny. They’re natively supported by the Arduino IDE, so setting them up won’t require any additional steps.
Seeed XIAO BLE nRF52840 Sense
Its “biggest” feature is being the smallest (worthwhile) board we could find, only 21 x 17.5 mm. It integrates a 6-axis IMU, a Bluetooth module, and a microphone. This, along with the onboard battery charger, makes it great for cramped spaces or weight-sensitive scenarios: RC cars, FPV drones, and wearables. It also supports TensorFlow Lite and can run AI applications natively. The main drawback is, of course, the limited amount of pins available.
- Specs: 64-MHz ARM Cortex-M4, 1-MB + 2-MB Flash, 256-kB SRAM
- Dimensions: 21 x 17.5 mm
- Features: 11 GPIO pins, 6-axis IMU, BT, microphone
- Price: ~$16
Seeed XIAO SAMD21
With the same form factor as the BLE nRF52840 Sense, this is a cheaper alternative without on-board sensors or wireless connectivity. A valid option for smaller projects on a tight budget, the SAMD21 is the cheapest board on this list. There’s a small but dedicated community active on Discord, too.
- Specs: 48-MHz SAMD21 Cortex-M0+, 256-kB flash, 32-kB SRAM
- Dimensions: 21 x 17.5 mm
- Features: 11 GPIO pins
- Price: ~$6
SparkFun
SparkFun makes a variety of handy Arduino-compatible boards, including the Pro Mini and Pro Micro. The Mini is made in collaboration with Arduino, which is apparent from its Arduino-blue PCB. And while the Pro Micro is made solely by SparkFun, it’s fully Arduino compatible.
Pro Micro
The Pro Micro is SparkFun’s answer to the Arduino Micro. It features the same microcontroller as the Arduino Micro and Leonardo, which gives the Pro Micro USB connectivity without a secondary processor. And just like the Arduino Micro, the SparkFun version can emulate a USB input device, such as a mouse or keyboard. This makes the Pro Micro especially useful for making custom computer peripherals and input devices. The Pro Micro is also available in several variants, including a 3.3-V logic version.
Another useful, and somewhat uncommon, feature of the Pro Micro is the onboard voltage regulator, which can accept up to 12-V DC. This makes battery-powered operation easy to implement without needing additional power circuitry, such as a buck-boost converter. This, coupled with an onboard fuse and reverse polarity protection, makes this one tough and versatile little board.
- Specs: ATmega32U4, 32-kB Flash, 2.5-kB SRAM, 1-kB EEPROM
- Dimensions and weight: 33 x 18 mm, 2 g
- Features: 12 digital I/O pins, PWM and analog support, UART and I2C communication
- Price: ~$20
Pro Mini
If there ever was a minimalist microcontroller board, the Pro Mini would be it. It has everything that you need and nothing you don’t. However, the spartan feature set doesn’t make the Pro Mini the best choice for those new to Arduino. To save on weight and components, the Pro Mini has done away with both the USB to serial chip and the USB port itself! This necessitates the use of an external USB to serial adapter for connecting to and programming the Pro Mini.
The Pro Mini features the ubiquitous ATmega328 microcontroller, the same one found in the Arduino Nano, among others. The features of this board are pretty much identical to those found in the Nano. The Pro Mini is ideal for projects where every square millimeter of space and milligram of weight matters.
- Specs: ATmega328, 32-kB Flash, 2-kB SRAM, 1-kB EEPROM
- Dimensions and weight: 33 x 18 mm, 2 g
- Features: 14 digital I/O pins, 8 analog and 6 PWM enabled pins, UART and I2C communication
- Price: ~$11
Teensy 4.1
Successor to the popular Teensy 3.6, the Teensy 4.1 makes upgradability its core feature. The base model has exposed pins for an Ethernet port, host USB port, and two pads for expandable memory. The choice of what to add or upgrade is left to the end-user.
Besides the three SPI and I2C ports, it also supports FlexIO, a programmable protocol emulator. FlexIO is capable of emulating various serial communication protocols, including UART, I2C, SPI, I2S audio, and PWM. It can be fully programmed and flashed using the Arduino IDE with the Teensyduino add-on. If you’re looking for something challenging for this specced-up board, check out our list of advanced Arduino projects.
If you’re looking for something a bit smaller, the Teensy 4.0 may be worth considering, as it’s a full inch shorter than the 4.1. The two boards have very similar features, however, the 4.0 is missing the Ethernet interface and SD card slot and is trimmed down in terms of I/O and Flash memory.
- Specs: 600-MHz ARM Cortex-M7, 8 MB Flash, 1024-kB RAM, 4-kB emulated EEPROM
- Dimensions: 60.96 x 17.78 mm
- Features: 55 GPIO pins, MicroSD slot, expandable memory
- Price: ~$30
DF Robot Beetle Board
While not an Arduino in the strictest sense, the DF Robot Beetle Board is Arduino compatible and features the same ATmega32U4 microcontroller found in the Arduino Leonardo. This microcontroller’s most notable feature is the built-in USB controller, which removes the need for a separate USB to serial chip, such as an FTDI or CH340. This allows the PCB to be quite tiny, since there only needs to be room for one IC.
The Beetle Board is a good choice for wearable projects and is designed with this function in mind. The through-hole pins and V-shaped pads make it easy to sew the board directly onto fabric. In addition, the one-sided layout also allows the board to lie flat, making it more comfortable for wearables and easier to fit into tight spaces for more general applications. The Beetle Board is also available in a Bluetooth-enabled version for projects that require wireless connectivity.
- Specs: ATmega32U4, 32-kB Flash, 2.5-kB SRAM, 1-kB EEPROM
- Dimensions and weight: 22 x 20 mm, 9 g
- Features: 10 digital I/O pins, PWM and analog support, UART and I2C communication
- Price: ~$9
Bonus: Raspberry Pi Pico
Although not technically speaking part of the Arduino ecosystem, the Raspberry Pi Pico carries out the same tasks and can be programmed via the Arduino IDE. So why not include it?
Small and cheap, the Pico runs on the internally designed RP2040 chip. In terms of specs and dimensions, it’s a good alternative to the Arduino Micro.
It has fewer on-board features compared to the Arduino Nano RP2040 Connect but is still supported by the Arduino IDE. It has the same interfaces as the Nano RP2040, though, plus the new PIO (programmable IO) pins. The latter allows the user to choose or create new communications protocols. For example, it’s possible to add another SPI/UART virtual controller or to generate a PWM signal without loading the CPU.
Still unclear what are the differences with an Arduino board? Check out our article about Raspberry Pi Pico vs. Arduino.
- Specs: 133-MHz Pi RP2040, 2-MB Flash, 264-kB SRAM
- Dimensions: 51 x 21 mm
- Features: 26 GPIO pins, 8 PIO pins, Micro-USB
- Price: ~$10
License: The text of "The Smallest Arduino Boards" by All3DP is licensed under a Creative Commons Attribution 4.0 International License.
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