物联网开发笔记（7）- 使用Wokwi仿真ESP32开发板实现LED灯点亮、按钮使用

上面几节我们使用Micrpython在Wokwi网站上实现了树莓派Pico开发板的仿真。学习了树莓派Pico的LED闪灯、按键操作等。以及Wokwi的使用，比如选中元器件后，按键盘“R”键切换方向，按键盘“Backspace”或者“Delete”删除原件，鼠标滚轮进行放大缩小，点击元器件上方的问号查看该元器件的使用说明等等。还有我们在编辑代码时，Wokwi默认按一次Tab键是两个空格，这里建议按两此tab键，即4个空格。当然默认也是可以的。

今天给大家分享一下ESP32 开发板，有了以上基础可以轻松入手。当然没有Pico开发板基础处按照我的讲解，同样也非常容易的上手。

一、环境搭建

很简单，首先打开Wokwi的网站

Wokwi - Online Arduino and ESP32 SimulatorArduino Simulator: Uno, Mega, ESP32, FastLED, LCD1602, Servo, Raspberry Pi Pico, Sensors. Designed for makers, by makers.https://wokwi.com/二、选择Micropython ESP32进行开发

附上ESP32开发板的针脚图：

三、然后进到如下开发界面

在右侧我们看到main.py文件是用来编辑我们的代码的。它旁边的diagram.json文件是用来显示和编辑硬件开发板和元器件的。保存我们编辑的代码可以使用Ctrl+s或者也可以点击左上方的保存按钮。你也可以分享你的项目给别人，通过SHARE按钮。再看右边，绿色的按钮是运行，加号按钮可以添加元器件到我们的开发板中，三个点按钮是其他的一些方便使用的功能。

四、点灯实验

我们还是从基础的点灯实验开始。

我们首先通过“+”加号按钮添加一个LED灯和一个电阻。我们通过diagram.json可以改变电阻的阻值。找到后我们把阻值改为470，默认是1000欧姆。

ESP32开发板GPIO34口和GPIO35口只能输入，不能作为输出（D34和D35脚）。

这里我们在LED灯正极（弯脚的那个脚是正极）接一个470欧姆的电阻，然后电阻的另一端连叫道GPIO25口上（D25脚），然后LED的负极接到开发板的GND上。

然后编写代码：

main.py


from machine import Pin # 导入Pin(开发板中Pin代表GPIO)
from time import sleep_ms # 导入时间
 
led = Pin(25, Pin.OUT)  # 定义一个LED灯，D25脚，输出
while 1:
    led.on()  # 灯亮
    sleep_ms(500)  # 等待500毫秒
    led.off()  # 灯灭
    sleep_ms(500)

diagram.json


{
  "version": 1,
  "author": "Anonymous maker",
  "editor": "wokwi",
  "parts": [
    {
      "type": "wokwi-esp32-devkit-v1",
      "id": "esp",
      "top": -2.77,
      "left": 41.04,
      "attrs": { "env": "micropython-20220618-v1.19.1" }
    },
    {
      "type": "wokwi-led",
      "id": "led1",
      "top": 46.75,
      "left": -75.86,
      "attrs": { "color": "red" }
    },
    {
      "type": "wokwi-resistor",
      "id": "r1",
      "top": 142.81,
      "left": -36.07,
      "attrs": { "value": "470" }
    }
  ],
  "connections": [
    [ "esp:TX0", "$serialMonitor:RX", "", [] ],
    [ "esp:RX0", "$serialMonitor:TX", "", [] ],
    [ "led1:A", "r1:1", "green", [ "v0" ] ],
    [ "led1:C", "esp:D25", "green", [ "v4.56", "h-28.75", "v-56.3", "h89.73", "v57.18" ] ],
    [ "r1:2", "esp:3V3", "green", [ "v65.54", "h143.57", "v-18.47" ] ]
  ]
}

五、LED连接方法说明

我们在连接是LED的正极并不一定连接在GPIO上，负极连接在GND上。只不过这是一种习惯性的连接方法。我们可以通过该表连接方法实现不一样的效果。例如：正极通过电阻接到3.3V上，负极接在D25上。代码不变同样可实现LED闪烁。

仔细观察会发现，效果反过来了，我们把等待的时间调整一下，效果更明显：我们代码期望是亮灯500毫秒，结果实际上是灭灯500毫秒。

main.py


from machine import Pin # 导入Pin(开发板中Pin代表GPIO)
from time import sleep_ms # 导入时间
 
led = Pin(25, Pin.OUT)  # 定义一个LED灯，D25脚，输出
while 1:
    led.on()  # 灯亮
    sleep_ms(500)  # 等待500毫秒
    led.off()  # 灯灭
    sleep_ms(1500)

diagram.json


{
  "version": 1,
  "author": "Anonymous maker",
  "editor": "wokwi",
  "parts": [
    {
      "type": "wokwi-esp32-devkit-v1",
      "id": "esp",
      "top": -2.77,
      "left": 41.04,
      "attrs": { "env": "micropython-20220618-v1.19.1" }
    },
    {
      "type": "wokwi-led",
      "id": "led1",
      "top": 46.75,
      "left": -75.86,
      "attrs": { "color": "red" }
    },
    {
      "type": "wokwi-resistor",
      "id": "r1",
      "top": 142.81,
      "left": -36.07,
      "attrs": { "value": "470" }
    }
  ],
  "connections": [
    [ "esp:TX0", "$serialMonitor:RX", "", [] ],
    [ "esp:RX0", "$serialMonitor:TX", "", [] ],
    [ "led1:A", "r1:1", "green", [ "v0" ] ],
    [ "led1:C", "esp:D25", "green", [ "v4.56", "h-28.75", "v-56.3", "h89.73", "v57.18" ] ],
    [ "r1:2", "esp:3V3", "green", [ "v65.54", "h143.57", "v-18.47" ] ]
  ]
}

当我们把正极接到D25上时，输出高电平亮灯，输出低电平灭灯。当把LED接到3.3V上时，这种揭发逻辑刚好反过来，当GPIO输出低电平的时候亮灯。

我们可以使用LED.value来设置和开始一样的效果。设置LED.value(0)，即亮灯的时候输出0。


from machine import Pin # 导入Pin(开发板中Pin代表GPIO)
from time import sleep_ms # 导入时间
 
led = Pin(25, Pin.OUT)  # 定义一个LED灯，D25脚，输出
while 1:
    led.value(0)  #led.on()  # 灯亮
    sleep_ms(500)  # 等待500毫秒
    led.value(1)  #led.off()  # 灯灭
    sleep_ms(1500)

diagram.json


{
  "version": 1,
  "author": "Anonymous maker",
  "editor": "wokwi",
  "parts": [
    {
      "type": "wokwi-esp32-devkit-v1",
      "id": "esp",
      "top": -2.77,
      "left": 41.04,
      "attrs": { "env": "micropython-20220618-v1.19.1" }
    },
    {
      "type": "wokwi-led",
      "id": "led1",
      "top": 46.75,
      "left": -75.86,
      "attrs": { "color": "red" }
    },
    {
      "type": "wokwi-resistor",
      "id": "r1",
      "top": 142.81,
      "left": -36.07,
      "attrs": { "value": "470" }
    }
  ],
  "connections": [
    [ "esp:TX0", "$serialMonitor:RX", "", [] ],
    [ "esp:RX0", "$serialMonitor:TX", "", [] ],
    [ "led1:A", "r1:1", "green", [ "v0" ] ],
    [ "led1:C", "esp:D25", "green", [ "v4.56", "h-28.75", "v-56.3", "h89.73", "v57.18" ] ],
    [ "r1:2", "esp:3V3", "green", [ "v65.54", "h143.57", "v-18.47" ] ]
  ]
}

这样就可以看到，输出结果和代码是对应的。想明白了没，不明白的找你师傅问一下哦！

五、按钮实验

硬件连接图：

代码：

main.py:


from machine import Pin # 导入Pin(开发板中Pin代表GPIO)
from time import sleep_ms # 导入时间
 
led = Pin(25, Pin.OUT)  # 定义一个LED灯，D25脚，输出
key = Pin(21, Pin.IN) # 定义一个按键，D21脚，输入
while 1:
    print(key.value())
    sleep_ms(500)

diagram.json


{
  "version": 1,
  "author": "Anonymous maker",
  "editor": "wokwi",
  "parts": [
    {
      "type": "wokwi-esp32-devkit-v1",
      "id": "esp",
      "top": -6.75,
      "left": 9.18,
      "attrs": { "env": "micropython-20220618-v1.19.1" }
    },
    {
      "type": "wokwi-led",
      "id": "led1",
      "top": 46.75,
      "left": -75.86,
      "attrs": { "color": "red" }
    },
    {
      "type": "wokwi-resistor",
      "id": "r1",
      "top": 78.75,
      "left": -33.98,
      "attrs": { "value": "470" }
    },
    {
      "type": "wokwi-pushbutton",
      "id": "btn1",
      "top": 74.95,
      "left": 152.32,
      "attrs": { "color": "green" }
    },
    {
      "type": "wokwi-resistor",
      "id": "r2",
      "top": 147.16,
      "left": 146.85,
      "attrs": { "value": "470" }
    }
  ],
  "connections": [
    [ "esp:TX0", "$serialMonitor:RX", "", [] ],
    [ "esp:RX0", "$serialMonitor:TX", "", [] ],
    [ "r1:2", "esp:D25", "green", [ "v0" ] ],
    [ "r1:1", "led1:A", "green", [ "v0" ] ],
    [ "led1:C", "esp:GND.2", "green", [ "v0" ] ],
    [ "esp:D21", "btn1:1.l", "green", [ "h0" ] ],
    [ "esp:3V3", "r2:1", "green", [ "v0" ] ],
    [ "r2:2", "btn1:1.r", "green", [ "v-2.57", "h39.33", "v-75.2" ] ],
    [ "btn1:2.r", "esp:GND.1", "green", [ "h7.57", "v35.18", "h-119.06" ] ]
  ]
}

我们通过打印看到，当按键没按时输出1，按键按下时输出0

请查看如下链接：

Wokwi Arduino and ESP32 Simulatorhttps://wokwi.com/projects/341691507896484436

今天就到这，下次我们继续带大家一起学习。谢谢！

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原文地址：https://blog.csdn.net/zhusongziye/article/details/126669348