输入、输出与现实世界

Every Arduino project is built from two flows: information coming in from the world, and signals going out to change it. 🙂

An input is anything that tells your board about its surroundings, like a button being pressed or a room getting warmer.

A sensor is an input device that measures something real, heat, light, or distance, and hands your board a number.

An output is how your board changes the world: lighting an LED, spinning a motor, or beeping a buzzer.

An actuator is an output that creates physical action, like a motor that moves or a speaker that makes sound.

The same Arduino pins handle both jobs. You simply tell each pin in code whether it should listen or speak.

You declare a pin's direction with one command. Here pin 13 is set up as an output so it can drive an LED.

To listen instead, you read a pin's value. This grabs the state of a button wired to pin 2 so your code can react.

The magic is connecting them: read an input, decide, then drive an output. That tiny chain is the core of every gadget.

A motion light reads a sensor for movement, then drives a lamp on. Input in, output out, just like you'll build.

Master inputs and outputs and you can build almost anything. Every project you'll make is just a clever mix of these two.

Let's sort inputs from outputs.

Inputs and sensors bring data in; outputs and actuators push action out. Read, decide, act, that loop powers every device. 🔁