BACKGROUND

A. Technical Field

This invention relates generally to the field of low power sensor systems.

B. Description of the Related Art

Proximity sensors, such as touch screens for cellphones and touch switch for lights, are widely used in today's consumer and industrial electronics. A proximity sensor typically functions by either (1) responding to a target object or an object's motion when the object is within the sensing range (e.g., a touch screen), or (2) directly detecting the distance between the object and the sensor (e.g. an infrared ranging sensor).

In the application of proximity sensors, the range of interest between the sensor and the target object can be either explicitly or implicitly specified. For example, a touch light switch typically functions only when a hand is placed within around 10 centimeters of the sensor. A three-dimensional (3D) hand gesture detection sensor for smart phones also works in similar ranges. Often, the proximity zone is directional, i.e., objects or motions can only be detected in front of the proximity sensor.

To measure the distance of an object, proximity sensors can use active emissions. Distance is determined by detecting the reflected emissions from the object. Typical emissions by the proximity sensors include infrared, ultrasonic, or any other suitable electromagnetic signals that can be bounced back from a target object. In some embodiments, the basic working principle of the ranging proximity sensor is similar to radars.

Active ranging proximity sensors can accurately sense whether an object is present or a motion happens in its proximity with well-defined range such as 10 centimeters, 35 centimeters, or any other suitable ranges. Traditional proximity sensors, however, typically consume more than 0.5 mA in current, which is less suitable for battery-powered systems. For example, one standard AA battery usually has the capacity of around 1000 mAh and can only support an active ranging proximity sensor for a few months. Design of the battery-operated sensor systems often requires a battery life that is longer than a year.

Therefore, it is desirable to provide methods and systems for a sensor system that consumes low power.

SUMMARY

In accordance with the disclosed subject matter, systems and methods are provided for a low power compound sensor system.

Disclosed subject matter includes, in one aspect, a compound sensor system includes a first sensor, a second sensor, a memory that stores a module, and a processor coupled to the first sensor, the second sensor, and the memory. The first sensor is configured to detect a parameter that indicates a likelihood of having a user enter or leave a target area, and, in response, send a first command signal to the processor. The processor is configured to run the module stored in the memory that is configured to cause the processor to receive the first command signal from the first sensor and send a second command signal to the second sensor based on receiving the first command signal. The second sensor is configured to operate at a sleep mode and switch to an active mode upon receiving the second command signal, and during the active mode the second sensor is configured to determine if the user enters or leaves the target area.

Disclosed subject matter includes, in another aspect, a method of determining a user enters or leave a target area using a compound sensor system. The method includes detecting, using a first sensor of the compound sensor system, a parameter that indicates a likelihood of having a user enter or leave a target area, and, in response, send a first command signal to a processor of the compound sensor system. The method includes sending, from the processor, a second command signal to a second sensor of the compound sensor system based on receiving the first command signal. The method includes switching the second sensor from a sleep mode to an active mode upon receiving the second command signal, and determining, using the second sensor, if the user enters or leaves the target area.

The present disclosure also discloses computer readable media that include executable instructions (e.g., computer program of instructions) operable to cause a device to perform the functions of the apparatuses described above.

There has thus been outlined, rather broadly, the features of the disclosed subject matter in order that the detailed description thereof that follows may be better understood, and in order that the present contribution to the art may be better appreciated. There are, of course, additional features of the disclosed subject matter that will be described hereinafter and which will form the subject matter of the claims appended hereto.

In this respect, before explaining at least one embodiment of the disclosed subject matter in detail, it is to be understood that the disclosed subject matter is not limited in its application to the details of construction and to the arrangements of the components set forth in the following description or illustrated in the drawings. The disclosed subject matter is capable of other embodiments and of being practiced and carried out in various ways. Also, it is to be understood that the phraseology and terminology employed herein are for the purpose of description and should not be regarded as limiting.

As such, those skilled in the art will appreciate that the conception, upon which this disclosure is based, may readily be utilized as a basis for the designing of other structures, methods, and systems for carrying out the several purposes of the disclosed subject matter. It is important, therefore, that the claims be regarded as including such equivalent constructions insofar as they do not depart from the spirit and scope of the disclosed subject matter.

These together with the other objects of the disclosed subject matter, along with the various features of novelty which characterize the disclosed subject matter, are pointed out with particularity in the claims annexed to and forming a part of this disclosure. For a better understanding of the disclosed subject matter, its operating advantages and the specific objects attained by its uses, reference should be made to the accompanying drawings and descriptive matter in which there are illustrated preferred embodiments of the disclosed subject matter.

