To control devices in the real world, you’ll need a computer system. As you search for the right system, one name will probably dominate all the online advice boards: the Arduino. Of course, “Arduino” is a blanket term for every board the open source hardware and software company produces. Many different models of Arduino boards are available— along with boards that people incorrectly refer to as Arduino products— and these boards feature varying abilities, form factors, and power requirements. We’ll attempt to clarify the choices available for beginners and introduce several board options that would be ideal for more experienced builders.
How to Choose an Arduino Board
Many different models of Arduino boards are available— along with boards that people incorrectly refer to as Arduino products— and these boards feature varying abilities, form factors, and power requirements. We’ll attempt to clarify the choices available for beginners and introduce several board options that would be ideal for more experienced builders.
We can categorize Arduino boards in several ways, but for this article, I will discuss things in terms of physical form factor.
Arduino Uno Class Boards
Uno class boards have become so prevalent that they function as something of a de facto standard, even though Arduino doesn’t design or make many of these devices.
Arduino Uno Specs – Setting the Standard
The Uno defines this form factor and features:
-20 digital I/O pins, six of which can function as analog inputs.
-Power delivered through a full-sized USB-B socket, or by a barrel power connector that supports voltages between 6 and 20 VDC.
-An ATmega328P microcontroller at its heart, running at a 16 MHz clock speed.
-32 KB of flash memory.
Perhaps most importantly, the device, which measures 68.6 x 53.4 mm at a weight of 25 grams, has become a default form factor in this space. Many expansion boards, or “shields,” plug into the Uno’s header arrangement, which all the boards in this category attempt to replicate. Beyond this, many non-Arduino boards also now use this form factor, allowing them to take advantage of the wide variety of expansion shields available.
Arduino Mega Specs – Expanded I/O and Memory
As its name implies, the Mega is physically larger than the Uno, clocking in at 101.52 mm in length and 53.3 mm in width. This extra space allows for the following features:
-A similarly mega 54 digital I/O pins (15 with PWM output), along with 16 analog pins.
-ATmega2560 microcontroller that runs at 16 MHz.
-256 KB of flash.
-Increased SRAM and EEPROM specs.
-Voltage inputs via a USB connector or barrel jack.
If you have a project that would benefit from the Uno’s abilities but needs more I/O or storage, the Mega 22560 is an excellent choice. Importantly, most Uno shields are compatible with the Mega, as the extra I/O is spread out on headers toward the bottom of the board.
Arduino Leonardo – Emulating Computer Input Device
The Arduino Leonardo features the same physical input arrangement as the Uno, though with slightly different capabilities, making it compatible with Uno shields. The big difference with this board is that it uses an ATmega32u4 microcontroller instead of the ATmega328P.
The ATmega32u4 can act as an HID device, such as a keyboard, mouse, foot pedal, or whatever kind of input you dream up. You could configure an auxiliary shortcut keyboard or command your computer to perform action “x” when sensor “y” is triggered. Leonardo also features the same 20 digital I/O pins as the Uno, but you can use 12 of those pins as analog inputs.
Arduino Due – Mega Form Factor, 32-Bit Computing
With the same form factor as the Mega and similar IO capabilities, you might mistake the Due for one of those boards. In fact, either board could do the same job in many instances. Under the hood, however, the Due provides a huge processing power boost to its counterpart. This 32-bit AT91SAM3X8E microcontroller features:
-84 MHz clock speed.
-512 KB of flash.
-A huge leap forward in SRAM memory: 96 KB, compared to 8KB on the Mega.
Arduino Yún Rev 2 – Leonardo + Linux
The Arduino Yún features the same specs as the Atmega32U4, but it adds an Atheros AR9331 Linux microprocessor to the package. The AR9331 allows for Ethernet and Wi-Fi connections, and the device also features a Micro-SD card reader for storage.
Arduino Miniature Basic Boards
With the introduction of the MKR series, Arduino firmly embraced the smaller IoT form factor. There are also several small boards that have been on the market for some time. Here are your options for embedding a board in small projects.
ArduinoNano – The Go-To Miniature
The Arduino Nano is one of my personal favorites and many other hackers would agree. This miniature performs nearly identically to the Arduino Uno, all with a tiny 18 x 45 mm footprint, coming in at less than a quarter of the size of its larger counterpart. It features:
-ATmega328P microcontroller found in the Uno.
-22 pins, eight of which can process analog signals.
-3.3V and 5V supply.
-7 to 12VDC power supply.
Whether you use it as the heart of a large assembly with header pins, or as something you quickly solder a few leads to for control, the Uno is a versatile board for your parts bin.
ArduinoMicro – Small, HID-Capable
Similar in size and appearance to the Nano, the Arduino Micro features a 48x18 mm PCB, along with a micro USB connector (as opposed to the Nano’s slightly larger mini USB).
Unlike the Nano, the board features an ATmega32U4 MCU, so like the Leonardo, it can perform keyboard and mouse emulation. You’ll find 20 I/O pins, 12 of which are capable of analog input. Given the built-in USB functionality and small size, the Micro would be a great choice for custom peripherals.
Arduino Pro Mini – Even Smaller
If the Nano and Micro aren’t small enough for the job, the Pro Mini measures in at a minuscule 18x33 mm. It features an ATmega328 MCU with 14 digital I/O pins, eight of which are analog, and it weighs less than 2 grams.
This board does not include a USB connector or circuitry. Without these features, the board can achieve its tiny size, but you’ll need to be comfortable programming it with an FTDI connection instead of USB. The board only has 12 digital I/O pins, four of which you can use as analog inputs.
One important note: Arduino has retired the Pro Mini board as an official Arduino product, but you can still find it relatively easily.
Arduino Pro Micro-Tiny HID Capable
The Pro Micro features the Pro Mini’s 18x33 mm form-factor, adds a micro USB connector, and subs in an ATmega32U4 processor for the ATmega328. This build gives it native USB functionality in a slightly smaller package than the Arduino Micro.
Important note: while users commonly refer to this board as an “Arduino Pro Micro,” it’s not an official Arduino product.
Arduino MKR Family
The Uno has been and will continue to be an excellent form factor for years to come. But with its MKR series, Arduino embraced a smaller board design for its newest IoT offerings. These boards are extremely powerful, but the hardware and software ecosystem surrounding them still has a way to go.
Arduino MKR Wi-Fi 1010 – Small Form Factor Wi-Fi
The MKR1000 was the first to take on this small 61.5 x 25 mm footprint, and the latest version is the MKR1010. The board features 22 digital I/O pins, seven of which are capable of analog input, and one of which functions as an analog output (shared with the A0 pin). A number of these pins are also capable of PWM output, and UART, SPI, I2C, and I2S communications are also available.
-Device features of the MKR Wi-Fi 1010 include:
-SAMD21 Cortex-M0+ processor.
-32-bit low power MCU, running at a clock speed of 48 MHz.
-Communication via Wi-Fi or Bluetooth using an onboard ESP32 module.
-RTC functionality.
-Accommodations for a LiPo battery.
-Six built-in LEDs.
Arduino MKR Zero – Powerful Chip, Built-in SD Card Reader
The MKR Zero features nearly identical specs to the Wi-Fi 1010. Instead of being Wi-Fi-capable, it has a built-in SD card slot. This means that you can play sound files without any extra hardware, but it also makes the MKR Zero an ideal platform for data logging. The board’s price range is similar to the Arduino Uno, so with its much-expanded processing power and small form-factor, the MKR Zero could be a great choice for a variety of projects.
Arduino MKR WAN 1300 – Long Distance Off-Grid Communications
The MKR WAN features a different battery and connection configuration from the MKR Zero and MKR Wi-Fi 1010, but it maintains the same SAMD21 Cortex-M0+ processor. The big difference in the MKR WAN is that instead of a Wi-Fi antenna, it features a LoRaWAN radio that allows it to communicate over very long distances— tens or even hundreds of kilometers in extreme cases—without any sort of external infrastructure.
Where available, the MKR WAN can also work with existing LoRaWAN infrastructure. This board makes a great platform to start experimenting with LoRaWAN, especially for long-range data gathering, communication, or even control operations.
Arduino MKR GSM 1400 – Cellular Data Transfer
This board features the same specs and LiPo battery connector as the MKR Wi-Fi 1010, but it utilizes a U-blox SARA-U201 GSM module for communication. Thusly equipped, the MKR GSM 1400 can connect to cellular networks worldwide for data transfer and control. You’ll need to source your own SIM card for network access, but if you’re in range of a cell tower, the device can provide reliable and high-speed data transfer.
Arduino MKR Vidor 4000 – FPGA and More
Every MKR board is impressively powerful, but if you want to combine every available feature with the capability to create your own features as needed, the Vidor 4000 is the board for you.
The device features an Arm Cortex-M0+ processor, but MKR added an Intel Cyclone 10CL016 field-programmable gate array (FPGA). This setup allows for a virtually limitless number of I/O configuration options and includes:
-Mini PCI express port.
-Micro HDMI connector.
-MIPI camera connector.
-Wi-Fi and Bluetooth module, opening up communications options even further.
The Vidor 4000 boasts an impressive list of specs, and given the nature of FPGAs, it’s difficult to even properly compare its performance to the other boards on this list. Suffice it to say, if you can’t find a board with all the features you need, there is a good chance the Vidor 4000 can fill the role nicely.
Conclusion
This list, though lengthy, doesn’t even begin to cover the boards that are inspired by Arduino boards and the surrounding ecosystem. Whether you need an FPGA-enabled Vidor 4000, or a tiny (but powerful) module like the Nano to flip a few light switches, it’s a good bet that there is a board available to fit your needs.