Скачать или смотреть Automatic PIR Sensor Fan with speed control (DIY)

This project was created by recycling an unused computer cooling fan.
The circuit was designed to use a 12Vdc power supply and consists of a PIR Sensor module, PWM Fan, and PWM Fan control circuit. In addition, this circuit is very simple, anyone can easily make it, and it can be used very usefully.
In the PIR Sensor module, there are two trimpot, one for controlling the “ON” delay time(5~200sec) and other for adjusting detection sensitivity(distance range of approximately 3-7 meters).
The rotation speed of the fan is determined by the value at which the variable resistor(1KΩ, PWM control board) is set, and can be arbitrarily varied at a desired speed.
When someone enters its sensing range, the fan operates, and when it leaves the sensing range, the fan stops operating.