制作一个简易的恒温控制器学习PID。 使用到ds18b20 5V加热器（TB有卖） 场效应管IRF 640N用于开通和关断加热器。 设置预设值，通过PID不断矫正加热器输出，达到预设温度(we made a simple pid controler based on 51 in order to learn pid theory.they can control temperature to get a stable figure.)

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