Arduino Shields

If you are learning Arduino or you want to expand possibilities, there are no doubts: before or after you will meet (or you met yet) in the term Arduino Shield.  This short article will guide you on what Aduino Shields are, why they can be incredibly useful and so many things to keep in mind just before buying your first one.

As you know, Arduino is born for prototyping, studying and realizing amazing ideas in electronics.

Alone, Arduino, is able to realize a really wide range of applications but you have to think at some Arduino Shields if you need to add something special and extraordinary new possibilities, like Bluetooth, WIFI or GSM connections, or drive motors or some other things. Everything will become simple and easy, even though if you are pretty a newbie.

This is the field where Shields play! Basically, they are ready-to-go electronic boards that can be easily mounted on top of the standard Arduino board, just like a shield (from which the name comes). In this way, a Shield, that carries on specific functionality, will expand the functions of a classical Arduino, simplifying our life from the Hardware point of view: we don’t have to worry about how to build the board, assembling components and stuffs like that. There are no specific needs and competencies required to us, what we need to do is simply mount the shield on top, that’s it. Another aspect to consider is that often those shields come with pre-cooked libraries (a piece of software) for correct operational, so a huge simplification is even done in front of Software implementation. And, surfing the Internet, often we can download well-explained documents that will help us in every single aspect of the life of that shield. So finally, thanks to an Arduino Shield, we can realize quickly what we need to.

The scenario is practically endless: we can find Display Shields of any kind, Shield for piloting motors, to connect to Ethernet networks with cabling or wirelessly using the standard Wi-Fi, to add some new sensors or interfaces, Shields, Shields and again… Shields.

To plug in a Shield on an Arduino, we will use the top connection available on every standard Arduino board, the blank headers with side connections, paying particular attention to the “pins“.

We need to be aware of how to select the right shield and carefully keep in mind some elements, just before to buy.


Normally, the Shields are compatible with Arduino Uno from which they inherited the disposition and functions of the physical pins, as shown in the picture up. The majority of them will be compatible with Arduino Mega. Indeed, take into account that an Arduino Mega shares part of the pins with the Arduino Uno expanding functionalities. For example, increased numbers of pins, some extra serial ports, increased memory and many other improvements.

Some shields are not compatible and changeable between them and this should be taken into account consulting the right documents before installing the shield on our Arduino.

Apparently, don’t exist (they are not so diffused) Shield for Arduino Nano or Mini. Those exist to be used inside other circuits or to build much more complex circuitry achieving specific needs or for special applications.


Another important factor that must be considered when you are approaching to select or buy a shield is his documentation.

Thanks to the right documentation you will be able to know if your selected shield is the one you need based on the desired application. You can get a wide range of different documentation sources like links, self-explanatory examples, manuals, and so on.

It could be the most important part of your experience with shields. Thanks to their diffusion and availability of any kind of support, examples, libraries, articles (like this you are reading) written by other users (more or less expert), you will enjoy the opportunities of expansion offered by those piece of hardware and software combined in one piece of electronics.

There is a burgeoning in number authoritative websites like Adafruit Industries or Sparkfun. They provide a wide range of documents and libraries for almost any shield sold by their e-commerce service.


You have to strictly keep in mind the different versions. Often the shield is provided or buyable in different versions, highlighted with indications like v1 or v2 or by using distinctive codes. It is really important to know it in advance because the different type of version can require a different version of libraries and in some extreme cases, some shields could not be totally compatible with some boards. And again docs and websites could help us.

Welding yes… or welding no?

When we are facing a ready-to-go shield we have only to plug it in without any extra effort. It’s simple!

It is available on the market a specific shield particularly made for prototyping or to build some special board that does not exist at all. Those shields give you the opportunity to welding components directly on the surface giving the flexibility to assembly whatever we need to reach the purpose.

More Shields?

And at the end, one shield does not exclude another one. It is possible to add one more shield as a pipeline on the same Arduino expanding the system.

But you need to pay attention when you proceed to expand your system with more than one shields because you have to check compatibility between them. This because of some Arduino’s pins are exclusively used for a specific function and cannot be used in conjunction with multiple shields at the same time. The documents available on the Internet will address you quickly and correctly.

I want to suggest you start from the websites below: