In the smart bathroom product field, infrared sensors have been applied widely in products such as auto faucets, automatic flushing urinals, flushing devices for toilet bowls, toilet seats spraying warm water, hand driers and toilet bowls equipped with warm-air fans.
Most of the infrared sensors used in traditional smart bathroom products operate in an active infrared sensing mode. That is, an infrared emitter emits a certain wavelength of infrared light, and after the infrared light is reflected from a human body and received by an infrared receiver, the strength of the reflected signal is determined to achieve automatic sensing determination. However, it is difficult to achieve automatic sensing determination with respect to some substances having a low reflectivity to infrared light, such as black clothes and hair. After the infrared emitter emits infrared light, only a very small part of the infrared light reflected by such a substance is received by the infrared receiver. Due to the insufficient strength of the reflected signal, the sensor is unable to determine whether there exists a subject, thus causing a failure of sensing.
In order to solve the problem of the failure of sensing in the traditional infrared sensing bathroom products, a position sensitive detector (PSD) is induced into the bathing automation field. The PSD controls whether the bathroom product where the PSD is located is to perform an operation such as water releasing and flushing by detecting whether the distance to a subject to be detected is within a preset range. Since the PSD achieves the automatic sensing function by determining the distance from itself to the subject instead of by determining the strength of the reflected signal, the defect existing in traditional infrared sensing that “the insufficient strength of the reflected signal causes a failure of sensing” can be overcome effectively.
At present, the PSDs used in the smart bathroom products are generally powered by a battery. By the factor of the operation principle of a PSD, its power consumption is generally larger than that of an ordinary infrared sensor mainly because of the following two aspects:
1. In order to increase the strength of the signal of the PSD for sensing an object having a low reflectivity, an emitting current larger than that of the ordinary infrared sensor is usually used for signal collection, which results in the increase of the emitting power consumption.
2. In order to increase the precision for detecting the distance to the object having a weak reflectivity by the PSD product, an approach of obtaining an average value of signals collected for multiple times in unit time is generally used.
Therefore, due to the service life of the battery, it is necessary to decrease the power consumption of a PSD product used in a smart bathroom product as much as possible to prolong the service life of the battery so as to reduce the inconvenience caused by the depletion of the battery and the frequent replacement of the battery, allowing the PSD product to be applied widely.
Hence, a method for decreasing power consumption of the PSD product is also needed urgently in the art.