What is GPIO and what can you use it for?

gpio pins computer


If you own a Raspberry Pi or other similar hobbyist computer, you may have noticed that it has a GPIO (General-Purpose Input-Output) function. Most users will never use GPIO, but if you want to build things, GPIO is essential.

RELATED: What Is the Raspberry Pi?

GPIO is a set of pins

At its most basic level, GPIO refers to a set of pins on your computer’s motherboard or expansion card. These pins can send or receive electrical signals, but are not designed for a specific purpose. This is why they are called “general-purpose” IO.

This is in contrast to common port standards such as USB or DVI. With those cables, each pin thenewsupdate into the connection has a specific purpose, which is determined by the governing body that created the standard.

GPIO puts you in charge of what each pin actually does. Although there are still different types of pins on the GPIO array.

Using the Raspberry Pi as an example again, you’ll find a few types of pins:

Pins that supply power at typical voltages such as 3.3V or 5V. This is to power connected devices that do not have their own power source, such as a simple LED. Ground stakes that do not provide power, but are required to complete some circuits. GPIO pins, which can be configured to send or receive electrical signals. Special purpose pins, which vary based on the specific GPIO in question.

GPIO implementations can vary by device in the exact details, but the idea is always to allow users to receive or send an electrical signal to almost anything.

RELATED: Build an LED Indicator With a Raspberry Pi (for Email, Weather, or Anything Else)

What is GPIO used for?

The most common use for GPIO is to control custom electronics. Whether you’re building your own robotic arm or a DIY weather station, a GPIO interface lets you customize signals so they control your equipment correctly.

A Raspberry Pi project with a breadboard. goodcat/shutterstock.com

GPIO interfaces are usually used in conjunction with a “breadboard”. Breadboards are a kind of temporary circuit boards. You can prototype circuits by adding, removing, or moving electronic components. Many projects that involve devices like a Raspberry Pi require you to mount your device on a breadboard and then connect it with wires to your GPIO pins.

Some advanced Raspberry Pi kits come with an integrated breadboard, such as the CrowPi 2 laptop, which contains both a Raspberry Pi and more sensors than you can shake a stick with.

One of the simplest GPIO projects for Raspberry Pi computers is to add a simple power button, which the stock board lacks.

Another popular device with GPIO is the Arduino microcontroller. This is not a full computer like a Raspberry Pi, but rather a device specifically designed to be programmable to control other equipment. For example, you can connect a light sensor to an Arduino and then program it to turn on your garden lights when the sun goes down. Arduinos have been instrumental in opening up the world of robotics and invention to people who might not otherwise have the resources to engage in engineering and programming.

The Raspberry Pi Foundation has its own Arduino competitor, in the form of the $4 Pico. The Pico has 30 GPIO pins, some of which can handle analog signals, rather than the more common digital pulses.

How to use GPIO

Aside from connecting your GPIO pins to the correct connections on your external circuit board or devices, your computer or microcontroller needs to know what to send over those wires or how to understand the signals entering the GPIO interface.

That means you need software, which you will have to write more often than not! On Raspberry Pi systems it is common to write software in Python that can tell the GPIO controller what to send or listen in on the signals coming in. After all, “Pi” refers to Python!

In particular, Python has two modules known as Rpi.GPIO and Gpiozero. By calling these modules, you can take control of the GPIO system and make it do your bidding.

The Arduino microcontrollers have their own programming language, which makes it very easy to put together projects. However, you can also use a special version of Python known as MicroPython.

The Dangers of GPIO

When you plug a USB device into a USB port with a certified USB cable, there’s almost no chance of something catastrophically going wrong. That’s because these IO standards have been carefully designed, tested, and tested a few more times to make sure they’re secure.

When it comes to GPIO, the money stops with you. You are the one who designs your interface and circuits. If you short out pins, connect power to things that shouldn’t be receiving power, or otherwise play fast and loose with your circuitry and connections, you could be left with a pile of dead components (and GPIO boards). This is why you may want to invest in a good Raspberry Pi Kit as they often come with both the hardware you need and practice projects so you can safely learn the ropes.

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