detect whether people moves according to the change of IR value
pin: int. The gpio pin which is attached by the sensor
trigger: any type. It is a trigger signal, and whenever it comes, the service will detect motion
bool: boolean. true means people moves (IR value changes) in the last 3s
It will detect whether people moves in every 1s, if people moves, the buzzer starts buzzing, otherwise, the buzzer stop buzzing.