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