The pyroelectric infrared sensor detects infrared radiation on the basis of the characteristics that the self-polarization of pyroelectric material changes with temoerature.Dual compensated sensing elements are applied to suppress the interference resulting from circumstance temoerature variation.As a result,the operating stability of the sensor is greatly improved.It can be widely used in many applications such as in intellectualized toy,automatic light switch control,and visitor acknowledgement etc,especially in the field fo intellectualized toy applications.