In the early 2000s, prototyping electronics was either expensive, complex, or both. That presented a problem for Massimo Banzi and his students at the Ivrea Interaction Design Institute, who couldn’t easily afford the $100 BASIC Stamp microcontroller projects at the time utilized. So, building on the work of one of his students, Hernando Barragá, Banzi, and his colleagues set out to make an inexpensive platform that would make building electronics easier.

The team built on Barragá’s Wiring platform which consisted of a printed circuit board, an ATmega168 microcontroller, and an IDE based on Processing. Banzi’s team forked the project and added support for the less expensive ATmega8 microcontroller, to help hit their target price for the board: a much more affordable $30.

That price point helped launch the Arduino – as the team called their board, after the pub Banzi and his team frequented – into the powerhouse of DIY electronics-building that it is today. While the newer Arduino Uno Rev3 uses the more powerful ATmega328p microcontroller, it’s maintained the sub-$30 price point, allowing hobbyists, students, and entrepreneurs alike to learn, build, and code for custom electronics devices without shelling out a fortune.

Since that first board was built, a variety of revisions, additions, and extensions of the platform have been made available to the DIY community. These include the Arduino Nano, a half-sized variant of the Uno designed for smaller electronics, the Uno Wi-Fi with a built-in wireless connection, and a collection of “shields” to add extra functionality, like more memory and storage, an ethernet connection, or motor controls.

For the unfamiliar, the range of boards can be daunting, but here we’ll walk through the basics of the Arduino, its variations, how to add new functionality with shields, and the kits that come with everything you need to get started.

Start Here: An Arduino Uno Introduction

The Arduino Uno is the main line of boards that most other Arduino devices are either derived from or connect to. Based on the ATmega328P microcontroller, it comes with 16 digital input/output pins, six of which can be used as pulse-width modulation outputs, meaning they can output a variable amount of power, simulating an analog output. Which is useful for, say, controlling the brightness of an LED.

It also comes equipped with 6 analog inputs, a 16MHz ceramic resonator (used to synchronize the clock signal), a USB port, and a power jack. With a simple USB cable, you can connect the Uno to your IDE and start writing and running your own software on the board, easy as that. The power jack gives you another option to supply power to your project once you’re ready to move away from the computer, but it’s not strictly necessary in the beginning, making the barrier to entry extremely low.

While many other electronics boards–including the Arduino Nano–use solderable pin holes, the pins on the Uno are designed so that wires can be removed and reused as many times as is necessary to design a finished product. If you’ve never used an Arduino before, a starter kit will not only come with an Uno board, but also a collection of LEDs, sensors, capacitors, and assorted lengths of wire. These components can be reused from one project to another, and the Uno itself is inexpensive enough that each time you decide to start a new project, it should be relatively easy to do so.

Variations On the Uno

The Arduino platform lets you design your own custom electronics for whatever specific need you have, like an automatic spray bottle that keeps the cats off the counter, or a fingerprint sensor for your garage door. Those specialty needs mean that the Uno isn’t necessarily a one-size-fits-all board, so Arduino offers a selection of variants to fit your needs.

The Arduino Nano, for example, is a much smaller board that takes up as little space as possible. It’s roughly half the size of a credit card, and is powered by a mini USB plug, making it easy to build this into a low profile casing. The similar Arduino Micro uses the same micro USB cable that’s standard with many Android smartphones, making it easy to connect to a computer, or find a handy power supply for your finished project.

There are a host of other variations including the 32-bit Arduino Zero which enables more complex smart IoT applications, the Uno Wi-Fi which comes with a built-in Wi-Fi connection, or the Arduino Mega which comes with a staggering 54 digital pins, 16 analog pins, and 4 serial ports for more complex projects. As you learn more about the kinds of projects you can make with Arduino, you’ll probably find a version of the board that’s best suited for your specific project.

Adding New Functionality With Shields

A “shield,” in Arduino terminology, is an accessory board that adds new functionality that your Arduino didn’t have before. To keep costs low, the basic Arduino Uno and most of its variants don’t come with features like Wi-Fi, Bluetooth, ethernet ports, or motor controls. Not all of your projects will require these features, so it makes sense to let you buy only what you need.

Instead, shields come separately and can be easily stacked on the base board to quickly extend the functionality of your Arduino. The Motor Shield, for example, lets you control relays, solenoids, DC and stepping motors. You can even get the Proto Shield that comes with an open prototyping grid, allowing you to build your own custom circuits and attach them like any other shield directly to the top of your Arduino.

Since Arduino is an open platform, there’s a massive array of third-party shields that can add tons of functionality to your Arduino, including playing music, using a camera, attaching a display, and plenty more. Whether you want to design the next hot smart home gadget, build the perfect custom device for a client, or build your own motion sensing musical instrument just to learn how it works, there’s an Arduino and accompanying shields that will be perfect for your project.