What Is GPIO, and What Can You Use It For?

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

GPIO Is a Set of Pins

At the most basic level, GPIO refers to a set of pins on your computer’s mainboard or add-on card. These pins can send or receive electrical signals, but they aren’t designed for any specific purpose. This is why they’re called “general-purpose” IO.

This is unlike common port standards such as USB or DVI. With those cables, each pin wired inside the connection has a designated 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 the example again, you’ll find a few types of pin:

• Pins that provide power at typical voltages such as 3.3V or 5V. This is to power connected devices that don’t have their own power source, such as a simple LED.
• Ground pins that do not output power, but are necessary 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 in the exact details on a per-device basis; but the idea is always to allow users to receive or send an electrical signal to almost anything.

What Is GPIO Used For?

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

GPIO interfaces are usually used in conjunction with a “breadboard”. Breadboards are a type of temporary circuit board. You can prototype circuits by adding, removing, or moving electronic components around. Many projects that involve devices like a Raspberry Pi have you assemble your device on a breadboard and then connect it to your GPIO pins using wires. One of the most simple GPIO projects for Raspberry Pi computers is to add a simple power button, which the standard board lacks.

How To Use GPIO

Apart 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 that are coming into the GPIO interface.

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

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

The Dangers of GPIO

When you plug a USB device into a USB port, using a certified USB cable, there’s an almost zero chance anything will go catastrophically wrong. That’s because these IO standards have been carefully designed, tested, and then tested some more to make sure they are safe.

When it comes to GPIO, the buck stops with you. You are the one designing your interface and circuitry. If you short pins, hook up power to things that should not get power, or otherwise play fast and loose with your circuits and connections, you could have a pile of dead components (and GPIO boards) on your hands. 

Read more: https://www.howtogeek.com/787928/what-is-gpio/