使用数字式温度传感器DS18B20采集周围的环境温度，单片机的定时器中断产生脉冲宽度调制控制双向可控硅，改变电机两端的电压，从而达到改变风速的目的。设定在一定温度范围内，对应的脉冲占空比比值，然后定时器中断当中形成相应占空比的PWM波，通过单片机的引脚去控制内部集成有过零电路的光电耦合MOC3041，光耦再去触发双向可控硅。-Use around the digital temperature sensor DS18B20 acquisition environment temperature, single-chip timer interrupt generating pulse width modulation control bidirectional silicon controlled rectifier, voltage change at both ends of the motor, so as to achieve the purpose of changing speed. Set in a certain temperature range, pulse duty ratio corresponding timer interrupt, and then form a corresponding duty cycle of the PWM wave, through the microcontroller pin to control the internal integration of a photoelectric coupling　MOC3041 zero circuit, opto coupler to trigger bidirectional thyristor.