Peripherals are devices that are not the computer's core architecture involved in memory and processing. Peripherals include input hardware, output hardware and storage devices.
A typical desktop computer could include:
GPIO ports are generic input and output ports that can be controlled directly by software. They are used on the circuit boards of computers like the Raspberry Pi and Arduino. They provide low-level connections that can be connected to switches, LED lights or electric relays. They can be used in programs to control systems such as a DIY burglar alarm or central heating system. Smartphones, desktop and laptop computers do not have GPIOs.
It can be easy to create your own basic peripheral using a Raspberry Pi, Arduino or other simple computing device.