Smallest Arduino: What Is The Best

Introduction to Arduino

Arduino is an open-source electronics platform based on easy-to-use hardware and software. It consists of a programmable circuit board (microcontroller) and a software Integrated Development Environment (IDE) for writing code and uploading it to the board. Arduino boards are able to read inputs – like light on a sensor or a finger on a button – and turn it into an output, such as activating a motor or turning on an LED.

The Arduino platform has become extremely popular with hobbyists, makers, students, and professionals due to its simplicity, versatility, and affordability. There are many different types and sizes of Arduino boards available, from full-size boards to very compact ones. In this article, we’ll focus specifically on the smallest Arduino boards and compare them to determine which are the best for various projects and uses.

Why Choose a Small Arduino Board?

There are several reasons you may want to opt for one of the smallest Arduino boards rather than a full-size one:

• Space constraints: If your project has very limited space, such as wearables or tiny robots, you’ll need a microcontroller that can fit.

• Weight: For drones, RC vehicles, and other projects where weight matters, a lighter board is preferable. The smallest boards weigh just a few grams.

• Lower power consumption: The compact boards typically run on less power, which is important if running on a small battery or coin cell.

• Cost: Smaller boards tend to be less expensive than the full-featured, full-size Arduinos. If you only need minimal I/O and memory, you can save money by going with a tiny board.

Of course, the trade-off is that the smallest Arduino boards have more limited capabilities and features than their larger counterparts. They have fewer I/O pins, less flash memory and SRAM, and some may lack features like USB ports or serial headers. However, for many projects, a mini Arduino is more than sufficient.

Comparing the Smallest Arduino Boards

Let’s take a look at some of the smallest Arduino boards and compare their key specs and features:

As you can see, these boards vary quite a bit in their dimensions, capabilities, and special features. How do you decide which one is the best for your needs? Here are some things to consider:

Physical Size

If size is your number one priority, the Nanite 85 is the clear winner at just 11.4 x 17.85mm. The Adafruit Gemma M0 and TinyDuino are also very compact. However, the Nanite 85 and Gemma M0 are also the most limited in terms of I/O and features.

The Seeeduino XIAO and Adafruit QT Py offer an impressive amount of functionality in a tiny footprint of around 20 x 18mm. These would be good choices for projects that need a lot of analog inputs, PWM outputs, a DAC, I2C, and/or SPI support.

Processor and Performance

Most of these boards use 32-bit ARM Cortex-M0+ processors, either from Microchip’s SAM D21 line or Nordic’s nRF52 series. These give you 48 MHz of computing power in a low-power package. The exceptions are the TinyDuino, ItsyBitsy 32u4, and Beetle boards which have 8-bit AVR processors running at 8 MHz, and the Nanite 85 with its ATtiny85 processor.

If processing power is a priority, you’ll want to stick with one of the 32-bit boards. The SAM D21 is more powerful than the AVR chips. For most basic Arduino projects though, the 8-bit boards are usually adequate.

Input/Output

Consider how many digital and analog I/O pins your project requires, and whether you need PWM, I2C, SPI, or a DAC. The Seeeduino XIAO really shines here with the most analog inputs, PWM channels, and a DAC in a tiny package. The QT Py, Nano 33 IoT, and MKR1000 also offer a good assortment of I/O.

If your I/O needs are simpler, one of the other boards like the Trinket M0, ItsyBitsy, or Beetle may suffice. The Nanite 85 and Gemma M0 are the most constrained.

Special Features

Some of these tiny boards pack in some unique built-in features:

• The Adafruit QT Py and Gemma M0 boards have a built-in NeoPixel RGB LED, great for adding visual feedback or a splash of color to your project.

• The Nano 33 IoT has an IMU and crypto chip in addition to WiFi and Bluetooth.

• The MKR1000 and Beetle have built-in LiPo battery charging circuitry.

• The TinyDuino Processor lets you stack additional “TinyShield” boards on top to add sensors, displays, radios, etc.

• The XIAO has a respectable 11 analog inputs and PWM channels plus a true analog output (DAC), unmatched for its size.

Consider which, if any, of these features would be useful to have built-in. Of course, you can always add your own sensors and radios to any board via the I2C or SPI pins. But having them on-board is convenient.

Price

Most of these boards are priced around $10-15 USD. The TinyDuino and MKR1000 are a bit spendier, while the Nanite 85 is under $5.

Generally, you can expect to pay a bit of a premium for the smallest boards compared to their larger counterparts due to the specialized chips and assembly required. But they are all quite affordable for the features you get. Price may not be the biggest factor unless you are making a large number of devices.

Choosing the Best Tiny Arduino Board

With all these factors in mind, which of these is the “best” smallest Arduino board? It really depends on your specific project needs. But here are some general recommendations:

Best All-Around: Seeeduino XIAO

The XIAO packs an impressive amount of I/O capabilities into a tiny 20 x 17.5mm board at a reasonable price point. With 11 analog inputs, 11 PWM outputs, an analog output (DAC), and plenty of flash and SRAM memory, it can handle a wide variety of Arduino projects. It’s versatile, capable, Arduino IDE-compatible, and has a solid community behind it. Unless you need wireless connectivity, a LiPo charger, or tons of flash memory, the XIAO can probably meet your needs in a very space-efficient package.

Best for Bluetooth Connectivity: Adafruit QT Py

While slightly larger than the XIAO, Adafruit’s QT Py board is another very capable mini Arduino with a built-in NeoPixel LED. But its secret weapon is the onboard ATSAMD21 chip which also provides Bluetooth support. Adafruit hasn’t enabled the Bluetooth functionality in Arduino yet, but it’s possible to use it with CircuitPython. So if you need a tiny Arduino with Bluetooth, the QT Py is your best bet. The onboard NeoPixel and STEMMA QT connector for plug-and-play I2C devices are nice bonuses.

Best for Beginners: Arduino Nano 33 IoT

For those just getting started with Arduino, the Nano 33 IoT provides a beginner-friendly board in a small package. It has WiFi and Bluetooth connectivity, an accelerometer, and a crypto chip for security. It also has a familiar form factor and pinout as the classic Arduino Nano. While not the smallest board available, it’s still very compact and offers a good balance of size, features, and ease-of-use. Arduino has great resources available for learning with this board.

Best on a Budget: Nanite 85

If you want to go absolutely tiny on a tight budget, the sub-$5 Nanite 85 is a fun option to play with. At just 11.4 x 17.85mm, it’s smaller than a US quarter. You’ll have to be comfortable with tight soldering to use it though. Its ATtiny85 processor is definitely a step down from the 32-bit boards, but it’s adequate for very simple Arduino projects and a good way to challenge yourself to write efficient code. It’s Arduino IDE-compatible and can run on a coin cell battery.

Tiny Arduino Project Ideas

So what can you actually make with these tiny Arduinos? Here are a few project ideas to get you started:

• Wearable Devices: Sew a LilyPad board into clothing to make light-up or sensor-enabled fashion pieces and accessories.

• Environmental Sensors: Build compact weather or air quality monitors to deploy around your home, office, or neighborhood.

• Mini Robots: Make palm-sized robots that can navigate mazes, follow lines, or respond to voice commands.

• Bluetooth Beacons: Configure a QT Py or other BLE-capable board as an iBeacon or Eddystone beacon for location-aware projects.

• Keychain Gadgets: Attach a tiny board to your keyring to make a handy flashlight, countdown timer, or password vault.

• Smart Home Automation: Tuck mini Arduinos into every room to control lights, appliances, and send sensor data to the cloud.

• Miniature Instruments: Create pocket-sized synthesizers, drum machines, or MIDI controllers.

• Tiny Arcade Games: Build keychain-sized versions of classic games like Snake, Tetris, or Breakout.

Of course, this is just scratching the surface. The possibilities are endless with these mighty mini microcontrollers!

FAQ

What’s the difference between Arduino and microcontrollers like the ATmega or ATtiny?

Arduino is an ecosystem and platform built around various microcontroller chips, most commonly the Atmel ATmega series. Arduino provides a beginner-friendly way to program these chips using C/C++ in the Arduino IDE, as well as a standardized board layout and hardware libraries. You can program an ATmega or ATtiny chip using the Arduino IDE, but standalone chips require more setup and wiring work compared to a plug-and-play Arduino board.

Can I use regular Arduino libraries and code with these mini boards?

In most cases, yes. The majority of these boards will work with Arduino sketches and libraries, since they have the same processor and memory as classic Arduino boards (albeit in a much smaller package). You may need to modify pin definitions and wiring, but the core code is usually compatible.

The exceptions would be the ATtiny boards like the Nanite 85, which are missing some hardware features and memory compared to mainstream Arduinos. Some libraries may not work on ATtiny, or may need to be modified.

How do I connect sensors, buttons, and other components to these tiny boards?

Many of the smallest boards like the Nanite 85 or Trinket M0 simply have numbered solder pads or Castellated Holes around the edges. You’ll need to solder wires or header pins to these pads to connect external components.

Some boards like the Beetle or XIAO have header pins pre-installed, which are breadboard-friendly. And boards like the QT Py have special connectors like the STEMMA QT port for plug-and-play access to I2C sensors and devices.

In general, connecting peripherals to these tiny boards isn’t much different than with a regular Arduino – you’ll just have fewer pins to work with and will often need adapter cables or steady hands for soldering.

I want to add Bluetooth or WiFi to my tiny Arduino project. What’s the best way to do that?

Some of these boards like the Nano 33 IoT have WiFi and/or Bluetooth (BLE) built in. If you know you need wireless connectivity, that’s the simplest approach.

For boards without built-in wireless, you can add an external radio module via the SPI or UART pins. These modules are available in very small sizes. For example, the Adafruit Airlift boards mate with several of their tiny SAMD21 boards to add WiFi and BLE.

I’m new to Arduino and electronics. Are these tiny boards a good place to start?

Most of these boards are designed for those with at least a bit of prior Arduino experience, since the small size can make wiring and programming a bit trickier. If you’re an absolute beginner, you may have an easier time starting with a more beginner-oriented board like the standard Arduino Uno, Adafruit METRO, or Arduboy before graduating to the tiny boards.

That said, the learning curve isn’t that steep – especially with boards like the Seeeduino XIAO that are breadboard-friendly and have plenty of digital I/O pins. And there’s definitely a “wow” factor in creating your first “tiny blinky” project! Adafruit and Sparkfun have great tutorials and resources for getting started with many of the boards mentioned here.