Arduino is an open-source electronics platform that has taken the maker community by storm, enabling anyone to create interactive projects with ease. At the heart of every Arduino project is the microcontroller board, which comes in many shapes and sizes.
For space-constrained and wearable projects, small Arduino boards are a must. With dimensions less than 2 x 2 cm, these mini boards pack a punch while taking up a tiny footprint.
In this post, we look at the 10 smallest Arduino-compatible boards on the market. Whether you’re looking to build a smartwatch, tiny robot, or any other miniaturized project, one of these boards will likely fit the bill.
1. Arduino Nano 33 BLE
The Arduino Nano 33 BLE measures only 18 x 45 mm but comes loaded with features. This board has built-in Bluetooth Low Energy (BLE) connectivity for wireless communication.
It is powered by the nRF52840 microcontroller, based on ARM Cortex M4 with a 64 MHz clock speed and 1 MB flash memory. The board has 30 GPIO pins, 6 analog inputs, and an onboard 9-axis inertial sensor. There is also a built-in USB connector for programming and power.
Despite the small size, the Nano 33 BLE can do quite a lot. It is great for IoT projects, robotics, wearables, and other applications requiring wireless connectivity in a compact form factor. The USB connector makes it easy to connect peripherals and reprogram the board on the fly.
2. Arduino Nano
The Arduino Nano is one of the smallest boards from the official Arduino family, measuring only 18 x 45 mm. It packs the Atmel ATmega328P microcontroller running at 16 MHz with 32 KB flash memory and 2 KB SRAM.
With 22 GPIO pins and 8 analog input pins, there is enough connectivity for most simple projects. The Nano draws power through the Mini-B USB connector which is also used for programming.
The Arduino Nano’s small size, breadboard-friendly design, and abundance of pins make it perfect for prototyping wearable tech and other portable projects. Its low price is also a big plus.
3. SODAQ SFF Board
The SODAQ SFF (Small Form Factor) board lives up to its name, squeezing an Arm Cortex-M4 chip into a tiny 16 x 19 mm circuit board. The SAMD21G18A microcontroller runs at 48 MHz with 256 KB flash and 32 KB SRAM.
Despite the tiny size, the SFF board includes 20 GPIO pins, 12-bit ADC, and native USB connectivity. There is an onboard battery charger and connector for a rechargeable LiPo battery. The power options and real-time clock make the SFF well suited for wearables and other battery-powered devices.
Programming is done through the native USB port. The Arduino IDE is supported with additional boards manager URL.
4. DFRobot Xiao nRF52840
For projects wanting Bluetooth 5 connectivity, the DFRobot Xiao nRF52840 is an excellent choice. It couples the Nordic nRF52840 with the popular Xiao form factor of only 17 x 20 mm.
This little board features a 32-bit Arm Cortex-M4F chip running at 64 MHz with 1 MB flash and 256 KB RAM. There is built-in USB connectivity, 30 GPIO pins, 10 capacitive touchpads, and a LiPo charging circuit. The onboard 2.4 GHz radio enables Bluetooth Low Energy and 6LoWPAN wireless connectivity.
Despite the small size, the Xiao nRF52840 can do it all from BLE projects to wearables, sensor nodes, robotics, and more. Programming is done via the USB port using the Arduino IDE.
5. Microduino Core+
Microduino takes a modular approach to miniaturized electronics. The Microduino Core+ board measures only 15 x 15 mm and can be used as a standalone Arduino-compatible development board.
The Core+ features an Atmel ATmega32U4 chip running at 16 MHz with 28 KB RAM and USB connectivity. There are 18 GPIO pins, 6 analog inputs, and two each of UART, SPI and I2C ports. The small footprint and standardized connector allow it to be integrated into stacked modules and other Microduino projects.
In addition to Microduino stacks, the Core+ is great for wearables or embedding into your custom PCB designs. Programming is done through the onboard USB port using the Arduino IDE.
6. Adafruit Trinket M0
The Adafruit Trinket M0 packs high performance into a tiny 1-inch square board. It features the same SAMD21 microcontroller used on the Arduino Zero running at 48 MHz with 256 KB flash and 32 KB RAM. There are 18 GPIO pins, 8 analog inputs, and native USB provided by the M0 chip.
Despite the diminutive size, the Trinket M0 can do a lot including driving NeoPixels, servos, sensors, and more. There is an onboard red LED and reset button. The USB port not only handles programming but also makes the Trinket show up as a USB Mouse or Keyboard.
The Trinket M0 is perfect when you want something smaller than a Pro Trinket but more capable than the basic Trinket. It hits a nice sweet spot between size and functionality.
7. SPARKFUN Pro Micro
The SparkFun Pro Micro comes in a narrow 24 x 34 mm footprint that can squeeze into tight spaces. At its heart sits the ATmega32U4 clocked at 16 MHz with 32 KB flash and 2.5 KB RAM.
With 18 GPIO pins, 12 analog inputs, and native USB connectivity, the Pro Micro packs a punch. There is also a handy 2 x 3 header on the bottom that turns it into an Arduino Leonardo, another small board.
The Pro Micro’s flexible design makes it suitable for use on breadboards, embedding within other devices, or as the brains of your wearable project. Programming is easy through the native USB port.
8. Digistump DigiX
The Digispark DigiX kicks it old school with a tiny 17 x 15 mm footprint compatible with classic Game Boy cartridges. This diminutive board is powered by the Attiny85 chip running at 16 MHz with 8 KB flash and 512 bytes RAM.
There are 6 GPIO pins, 2 PWM outputs, analog input, and an onboard RGB LED. Despite the retro design and low cost, the DigiX can drive RGB LEDs, sensors, small OLEDs and more. Program it using the Arduino IDE with Digistump boards package.
The DigiX is a great choice for chiptune music projects, retro gaming, and other fun miniature creations. It also makes an easy introduction to bare-bones microcontroller programming.
9. Adafruit Circuit Playground Express
The Circuit Playground Express packs tons of functionality into a compact 51 x 38 mm board. Inside is the same powerful SAMD21G18A processor as the Arduino Zero running at 48 MHz with 256 KB flash and 32 KB RAM.
There are 23 GPIOs, capacitive touch pads, 8 RGB NeoPixel LEDs, sensor inputs including temperature, light and sound, speaker output, and Bluetooth Low Energy. The onboard battery charger and connector enable portable projects.
While not the smallest board, the Circuit Playground Express shows just how much can be fit into a thumb-sized package. It is easy to program via USB and ideal for wearables, electronics experimentation and teaching coding fundamentals.
10. TinyCircuits TinyShield Processor Board
Last but not least is the Processor Board from TinyCircuits. At only 15 x 15 mm, it can claim the title of world’s smallest Arduino. The Processor Board is built around the ATtiny85 chip running at 8 MHz with 8 KB flash and 512 bytes RAM.
Despite the size, it packs 6 GPIO pins, 2 PWM outputs, and an analog input. There is a tiny switch, RGB LED, and the ability to interface with TinyScreen OLED displays. The board can be programmed via an SPI interface.
The TinyShield ecosystem offers boards, sensors, motors and more that stack together with magnets. The Processor Board slots right into this miniature world of electronics modules. TinyCircuits offers a range of tiny robots, games, and more built from these tiny boards.
Conclusion
While tiny, these minimalist Arduino boards pack connectivity for small-scale projects. When size and weight matter, choose one of these micro-sized boards to build portable, wearable, and highly integrated electronics. They are also convenient and inexpensive for embedding into custom designs.
We looked at 10 of the smallest Arduino-compatible options here but new boards are hitting the market all the time. Whether you need built-in Bluetooth, battery charging, or high performance, there is a mini Arduino board perfect for your next compact project.
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