🔥 PID温控实战：用ESP32打造恒温控制系统

ESP32          →  外设
────────────────────────────────
3.3V           →  DHT22 VCC
GND            →  DHT22 GND
GPIO 4         →  DHT22 DATA

3.3V           →  SSD1306 VCC
GND            →  SSD1306 GND
GPIO 21 (SDA)  →  SSD1306 SDA
GPIO 22 (SCL)  →  SSD1306 SCL

GPIO 26        →  SSR 输入端 (+)
GND            →  SSR 输入端 (-)

3.3V           →  KY-040 VCC (+)
GND            →  KY-040 GND
GPIO 32        →  KY-040 CLK
GPIO 33        →  KY-040 DT
GPIO 25        →  KY-040 SW (按键)

SSR输出端      →  加热片一端
12V电源(+)     →  加热片另一端
12V电源(-)     →  SSR输出端另一端
        

// ===== PID 恒温控制器 — ESP32 + DHT22 + SSD1306 + SSR ===== #include <DHT.h> #include <Adafruit_SSD1306.h> #include <Wire.h> // === 引脚定义 === #define DHTPIN 4 #define DHTTYPE DHT22 #define SSR_PIN 26 #define ENC_CLK 32 #define ENC_DT 33 #define ENC_SW 25 // === PID 参数 === double Kp = 15.0, Ki = 0.8, Kd = 5.0; double setpoint = 40.0; // 目标温度 ℃ double integral = 0, prevError = 0; unsigned long lastTime; const int PWM_FREQ = 1; // 1Hz PWM (SSR用低频) const int PWM_RES = 10; // 10位分辨率 0-1023 DHT dht(DHTPIN, DHTTYPE); Adafruit_SSD1306 display(128, 64, &Wire, -1); // === PID 计算 === double computePID(double current) { unsigned long now = millis(); double dt = (now - lastTime) / 1000.0; if (dt < 1.0) dt = 1.0; // 最小1秒采样周期 lastTime = now; double error = setpoint - current; // 积分抗饱和：限制积分累积 integral += error * dt; if (integral > 100.0) integral = 100.0; if (integral < 0.0) integral = 0.0; double derivative = (error - prevError) / dt; prevError = error; double output = Kp * error + Ki * integral + Kd * derivative; if (output > 1023) output = 1023; if (output < 0) output = 0; return output; } // === 编码器读取 === volatile int encoderPos = 40; void IRAM_ATTR readEncoder() { static int lastCLK = digitalRead(ENC_CLK); int clk = digitalRead(ENC_CLK); int dt = digitalRead(ENC_DT); if (clk != lastCLK && clk == LOW) { if (dt != clk) encoderPos += 1; else encoderPos -= 1; if (encoderPos < 10) encoderPos = 10; if (encoderPos > 120) encoderPos = 120; } lastCLK = clk; } void setup() { Serial.begin(115200); dht.begin(); display.begin(SSD1306_SWITCHCAPVCC, 0x3C); // SSR: 1Hz PWM, 10-bit ledcAttach(SSR_PIN, PWM_FREQ, PWM_RES); pinMode(ENC_CLK, INPUT_PULLUP); pinMode(ENC_DT, INPUT_PULLUP); pinMode(ENC_SW, INPUT_PULLUP); attachInterrupt(ENC_CLK, readEncoder, CHANGE); lastTime = millis(); display.clearDisplay(); } void loop() { // 1. 读取温度 float temp = dht.readTemperature(); if (isnan(temp)) temp = setpoint; // 读取失败用设定值兜底 // 2. 按键重置积分 if (digitalRead(ENC_SW) == LOW) { integral = 0; delay(200); } // 3. 更新设定温度 setpoint = encoderPos; // 4. PID 计算 + PWM输出 double pwmVal = computePID(temp); ledcWrite(SSR_PIN, (int)pwmVal); // 5. OLED 显示 display.clearDisplay(); display.setTextSize(1); display.setTextColor(SSD1306_WHITE); display.setCursor(0, 0); display.printf("目标: %.1f C", setpoint); display.setCursor(0, 12); display.printf("当前: %.1f C", temp); display.setCursor(0, 26); display.printf("输出: %d / 1023", (int)pwmVal); // 进度条 (输出功率可视化) int barW = map((int)pwmVal, 0, 1023, 0, 100); display.drawRect(0, 42, 128, 12, SSD1306_WHITE); display.fillRect(2, 44, barW, 8, SSD1306_WHITE); display.display(); // 6. 串口输出 Serial.printf("目标:%.1f 当前:%.1f PWM:%d\n", setpoint, temp, (int)pwmVal); delay(1000); // 1秒控制周期 }

#include <WiFi.h> #include <WebServer.h> WebServer server(80); void handleJSON() { char json[200]; sprintf(json, "{\"temp\":%.1f,\"set\":%.1f,\"pwm\":%d}", temp, setpoint, (int)pwmVal); server.send(200, "application/json", json); } void setup() { WiFi.begin("SSID", "PASSWORD"); server.on("/api/temp", handleJSON); server.begin(); }