[嵌入式]arduino-esp32--按键，输入模式设置 03

注意管脚号。上面的GPIO2接的是板载的LED。我们用一根杜邦线，一个接GPIO15，一个先不接，后面需要的时候，快碰一下GND，相当于接地，类似按键的效果了。

打开案例代码，稍微阅读一下，然后修改一下。


注意，将上面的管脚修改，对应自己的设计。
我们打算是IO15是按键，IO2是板载LED灯。
所以修改。

注意如何设置输入输出模式，OUTPUT和INPUT。
如何读取某个管脚的电平状态。

/*
  Button

  Turns on and off a light emitting diode(LED) connected to digital pin 13,
  when pressing a pushbutton attached to pin 2.

  The circuit:
  - LED attached from pin 13 to ground through 220 ohm resistor
  - pushbutton attached to pin 2 from +5V
  - 10K resistor attached to pin 2 from ground

  - Note: on most Arduinos there is already an LED on the board
    attached to pin 13.

  created 2005
  by DojoDave <http://www.0j0.org>
  modified 30 Aug 2011
  by Tom Igoe

  This example code is in the public domain.

  https://www.arduino.cc/en/Tutorial/BuiltInExamples/Button
*/

// constants won't change. They're used here to set pin numbers:
const int buttonPin = 15;     // the number of the pushbutton pin
const int ledPin =  2;      // the number of the LED pin

// variables will change:
int buttonState = 0;         // variable for reading the pushbutton status

void setup() {
  // initialize the LED pin as an output:
  pinMode(ledPin, OUTPUT);
  // initialize the pushbutton pin as an input:
  pinMode(buttonPin, INPUT);
}

void loop() {
  // read the state of the pushbutton value:
  buttonState = digitalRead(buttonPin);

  // check if the pushbutton is pressed. If it is, the buttonState is HIGH:
  if (buttonState == HIGH) {
    // turn LED on:
    digitalWrite(ledPin, HIGH);
  } else {
    // turn LED off:
    digitalWrite(ledPin, LOW);
  }
}

将上面的代码编译，下载。

用杜邦线，接GPIO15，一个碰一下GND，看下LED灯有没有变化。