ESP32 控制继电器

用 ESP32 的 GPIO4 控制继电器模块吸合 / 断开。仿真里用 LED + 电阻 模拟被控负载：继电器接通时 LED 亮，断开时 LED 灭，周期各 5 秒。可先在 Wokwi 在线仿真，再上真机。

在线仿真

1. 打开 https://wokwi.com/
2. My projects → New project → 选择 ESP32 → MicroPython
3. 将下方 main.py、diagram.json 分别粘贴到对应文件
4. 点击 Start 运行，观察继电器动作与 LED 亮灭

main.py

from machine import Pin
import time

relay = Pin(4, Pin.OUT)  # GPIO4 → 继电器 IN

while True:
    relay.on()           # 吸合，负载通路
    time.sleep(5)
    relay.off()          # 断开，负载开路
    time.sleep(5)

diagram.json

{
  "version": 1,
  "author": "ESP32 Relay LED Demo",
  "editor": "wokwi",
  "parts": [
    { "type": "wokwi-esp32-devkit-v1", "id": "esp", "top": 0, "left": 0, "attrs": {} },
    { "type": "wokwi-relay-module", "id": "relay", "top": 77, "left": 182.4, "attrs": {} },
    { "type": "wokwi-led", "id": "led", "top": -22.8, "left": 435.8, "attrs": { "color": "red" } },
    {
      "type": "wokwi-resistor",
      "id": "r1",
      "top": 70.6,
      "left": 469.55,
      "rotate": 270,
      "attrs": { "value": "220" }
    },
    { "type": "wokwi-vcc", "id": "vcc1", "top": -66.44, "left": 345.6, "attrs": {} },
    { "type": "wokwi-gnd", "id": "gnd1", "top": -67.2, "left": 373.8, "attrs": {} }
  ],
  "connections": [
    [ "relay:VCC", "esp:VIN", "red", [ "v-115.2", "h-201.6", "v177.7" ] ],
    [ "relay:GND", "esp:GND.2", "black", [ "h-9.6", "v-115.6", "h-182.4", "v158.6" ] ],
    [ "relay:IN", "esp:D4", "gold", [ "v-0.2", "h-81.1" ] ],
    [ "relay:NO", "r1:1", "green", [ "h0" ] ],
    [ "r1:2", "led:A", "green", [ "h0", "v-27.6" ] ],
    [ "led:C", "gnd1:GND", "green", [ "v0", "h-57.2" ] ],
    [ "vcc1:VCC", "relay:COM", "red", [ "v0" ] ]
  ],
  "dependencies": {}
}

接线说明

控制端（ESP32 ↔ 继电器模块）

ESP32	继电器模块	说明
VIN / 5V	VCC	模块供电
GND	GND	共地
GPIO4	IN	控制信号

负载端（本例用 LED 模拟市电灯）

用CC 模拟火线、GND 模拟零线、LED 模拟灯泡：

仿真接线	对应市电
VCC → 继电器 COM	火线 → COM
继电器 NO → 220Ω → LED 正极	NO → 灯
LED 负极 → GND	灯另一端 → 零线

吸合时：VCC(火线) → COM → NO → 电阻 → LED → GND(零线)，LED 点亮。

真机控灯同此：火线进 COM，NO 接灯，灯另一端接零线。务必断电接线，注意绝缘与安全。低电平触发的模块可能与本例电平逻辑相反，以模块丝印为准。