“Arduino” itself is not a specific board type or microcontroller. Rather, Arduino refers to a whole family of boards that have different advantages and disadvantages. Choosing the right one for your project is no small feat and some thought should be given to the one that you use. In this article we will learn about some of the different type of Arduino boards and when they should be used.
Popular Arduino Boards
While there are many varieties of Arduino boards on the market, there are a handful that are most commonly seen. The most commonly used Arduino boards by both engineers and hobbyists include:
- Arduino UNO
- Arduino Nano
- Arduino Due
- Arduino Mega
The UNO is arguably the most popular Arduino. It is powered by an Atmega328 processor operating at 16MHz, includes 32KB of program memory, 1KB of EEPROM, 2KB of RAM, has 14 digital I/O, 6 analog inputs, and both 5V and 3.3V power rails.
The Arduino UNO has a pin header arrangement that is rapidly becoming the industry standard for development boards, making it compatible with most development board shields on the market.
A power jack is included on the UNO, allowing it to be powered by an external wall wart. There is also a VIN option available for connecting the UNO to batteries.
The physical dimensions of the UNO (69mm x 54mm) make it a small development board that can easily fit into many projects and the four screw holes allow designers to securely fit them into place.
The Arduino Nano is essentially an Arduino UNO shrunk into a very small profile, making it very convenient for tight spaces and projects that may need to reduce weight wherever possible.
Like the UNO, the Nano is powered by an Atmega328 processor operating at 16MHz, includes 32KB of program memory, 1KB of EEPROM, 2KB of RAM, has 14 digital I/O, 6 analog inputs, and both 5V and 3.3V power rails.
(Note - Arduino Nano boards before V3.0 used the ATmega168 which essentially has half the specs.)
The Nano, unlike the UNO, cannot connect to Arduino shields but it has pin headers which make it useful for breadboard prototyping or in PCBs with the use of a socket. Often, Arduino Nano boards are the cheapest Arduino board option available making them cost-effective for larger projects.
Update: In July 2019, Arduino announced two Nano boards, the Nano 33 BLE and BLE Sense which come with onboard sensors. Check them out!
The Arduino Due is one of the larger boards and is also the first Arduino board to be powered by an ARM processor.
While the UNO and Nano operate at 5V, the Due operates at 3.3V—this is important to note, because overvoltage will irreparably damage the board. Powered by an ATSAM3X8E Cortex-M3 running at 84MHz, the Due has 512KB of ROM and 96KB RAM, 54 digital I/O pins, 12 PWM channels, 12 analog inputs, and 2 analog outputs.
The Due does not have any on-board EEPROM and is one of the more expensive Arduino boards. While the Due has a large number of pin headers for connecting to the many digital I/O, it is also pin-compatible with standard Arduino shields. Software compatibility with the Due cannot be guaranteed.
Arduino Mega 2560
The Arduino Mega is somewhat similar to the Due in that it also has 54 I/O. However, instead of being powered by an ARM core, it instead uses an ATmega2560.
The CPU is clocked at 16MHz and includes 256KB of ROM, 8KB of RAM, 4KB of EEPROM, and operates at 5V making it easy to use with most hobby friendly electronics.
The Arduino Mega has 16 analog inputs, 15 PWM channels, a pinout similar to the Due, and is hardware compatible with Arduino shields. Like the Due, software compatibility with the Mega cannot always be guaranteed.
Choosing the Right Arduino for Your Project
Now that we looked at some of the details about each board, optimal uses of each board can be determined.
Although the UNO is the most popular board, all boards have excellent support through online forums thanks to the common architecture and the use of a common language and IDE. This means that you are unlikely to fall into device-specific traps that could prevent a piece of code from working because of hardware configurations or inherent bugs.
Arduino code can be easily transferred to different boards with virtually no changes which is highly beneficial to any designers wanting to change their mind about what board their project will use.
The deciding factor each project will use comes down to two basic things: hardware and cost. While the cost aspect of each Arduino is obvious (the lowest cost option is always the preference), the hardware may not be so easy to determine. When looking at hardware the following should be considered:
- Physical dimensions
- CPU power
- Memory size
- I/O capabilities
- On-board peripherals
When it comes to physical dimensions the Arduino Nano is the smallest and is a very portable device. The UNO is a medium sized development board but is still small enough to be mounted to many projects including remote-controlled devices such as RC cars and boats. The Mega and Due are much larger boards which makes them difficult to use in space restricted applications.
If a project requires high processing power, the Due comes out on top with its powerful ARM core and large RAM/ROM. While the Mega is a large Arduino with plenty of GPIO, its CPU speed is still the same as that found on the UNO and Nano (same Mega family) and so there is no speed advantage to using the Mega.
The UNO and Nano use the same processor which means that in terms of hardware and peripherals the UNO and Nano are identical. If a project requires plenty of GPIO, the Due and Mega are the obvious choices. An application that does not require a strong CPU but needs plenty of GPIO will do well with the Mega.
Analog projects can be done with all the Arduino boards, but the Due stands out with 12 analog inputs and 2 analog outputs.