init

fan.py

@@ -0,0 +1,149 @@
+import pigpio
+import time
+import json
+import math
+
+class LowPassFilter:
+    def __init__(self,fc,Ts):
+        self.fc = fc
+        self.Ts = Ts
+        b = 2.0 * math.pi * self.fc * self.Ts
+        self.alpha = b / (b + 1)
+        self.last_value = 0
+
+    def filter(self,value):
+        out = self.last_value + self.alpha * (value - self.last_value)
+        self.last_value = out
+        return out
+
+
+
+# =====================
+# GPIO 定义
+# =====================
+PWM_PIN = 18
+TACH_PIN = 23
+
+# =====================
+# PID 参数（需要调）
+# =====================
+Kp = 1.0
+Ki = 0.01
+Kd = 0.03
+
+TARGET_TEMP =60.0  # 目标温度
+
+# =====================
+# 全局变量
+# =====================
+pulse_count = 0
+last_time = time.time()
+
+integral = 0
+last_error = 0
+
+# =====================
+# TACH 回调
+# =====================
+def tach_callback(gpio, level, tick):
+    global pulse_count
+    pulse_count += 1
+
+
+# =====================
+# 读取 CPU 温度
+# =====================
+def get_temp():
+    with open("/sys/class/thermal/thermal_zone0/temp") as f:
+        return int(f.read()) / 1000
+
+# =====================
+# 计算 RPM
+# =====================
+def get_rpm():
+    global pulse_count, last_time
+
+    now = time.time()
+    dt = now - last_time
+
+    count = pulse_count
+    pulse_count = 0
+    last_time = now
+
+    # 2 脉冲/转
+    rpm = (count / 2) / dt * 60
+    return rpm
+
+# =====================
+# PID 控制器
+# =====================
+def pid_control(temp):
+    global integral, last_error
+
+    error = temp - TARGET_TEMP
+    integral += error
+    intergral = max(-100,min(100,integral))
+    derivative = error - last_error
+
+    output = Kp * error + Ki * integral + Kd * derivative
+    last_error = error
+
+    return output
+
+if __name__=="__main__":
+    temp_low_pass = LowPassFilter(1,0.1)
+    duty_low_pass = LowPassFilter(0.5,0.1)
+    # =====================
+    # 初始化 pigpio
+    # =====================
+    pi = pigpio.pi()
+    if not pi.connected:
+        exit()
+
+    pi.set_mode(TACH_PIN, pigpio.INPUT)
+    pi.set_pull_up_down(TACH_PIN, pigpio.PUD_UP)
+    pi.callback(TACH_PIN, pigpio.FALLING_EDGE, tach_callback)
+
+    # 设置 PWM（25kHz）
+    pi.set_PWM_frequency(PWM_PIN, 25000)
+    pi.set_PWM_range(PWM_PIN, 255)
+    # =====================
+    # 主循环
+    # =====================
+    try:
+        while True:
+            temp = temp_low_pass.filter(get_temp())
+            rpm = get_rpm()
+
+            pid_out = pid_control(temp)
+
+            # 转换为 PWM（限制范围）
+            duty = int(duty_low_pass.filter(max(0, min(255, int(pid_out * 5)))))
+
+            # 最小转速保护
+            if duty < 10:
+                duty = 10
+
+            pi.set_PWM_dutycycle(PWM_PIN, duty)
+
+            # print(f"\rTemp={temp:.1f}C RPM={rpm:.0f} PWM={duty}                      ", end="", flush=True)
+
+            # 把实时状态写到内存盘（/dev/shm 不伤SD卡），其他程序直接读这个JSON即可
+            try:
+                with open("/dev/shm/fan_status.json", "w") as f:
+                    json.dump({"temp": temp, "rpm": rpm, "pwm": duty, "is_stalled": (duty > 100 and rpm < 500)}, f)
+            except Exception:
+                pass
+
+            # 风扇故障检测
+            if duty > 100 and rpm < 500:
+                print("\n⚠️ Fan may be stalled!")
+
+            time.sleep(0.1)
+
+    except KeyboardInterrupt:
+        pass
+
+    finally:
+        pi.set_PWM_dutycycle(PWM_PIN, 0)
+        pi.stop()