Event detecting device with low power consumption

Abstract

An event detecting device operates in a driving mode or a parking mode. In the driving mode, the event detecting device performs high quality video recording using an image-capturing circuit. In the parking mode, the event detecting device periodically activates the image-capturing circuit for event detection and starts to perform low quality video recording after detecting a specific event.

What is claimed is: 
     
         1 . An event detecting device, comprising:
 a built-in power supply;   an image-recording module, comprising:
 an image-capturing circuit performing a first video recording function in a driving mode and performing a second video recording function or a photograph function in a parking mode; 
 a module timing circuit configured to periodically activate the image-capturing circuit in the parking mode for performing the photograph function; and 
 a processing circuit detecting a specific event according to an image obtained by the image-capturing circuit when performing the photograph function and outputting a wakeup signal when detecting the specific event; 
   a control module activating the image-capturing circuit for performing the second video recording function when receiving the wakeup signal; and   a system timing circuit configured to provide a reference clock signal according to which the image-capturing circuit performs the first or the second video recording function;   wherein the module timing circuit and the system timing circuit are different circuits; and   wherein the event detecting device is operated in the driving mode when the event detecting device is not powered by the built-in power supply, and the event detecting device is operated in the parking mode when the event detecting device is powered by the built-in power supply.   
     
     
         2 . The event detecting device of  claim 1 , further comprising:
 a memory module for storing a data obtained by the image-capturing circuit when performing the first or the second video recording function.   
     
     
         3 . The event detecting device of  claim 1 , wherein the module timing circuit consumes less power than the system timing circuit. 
     
     
         4 . The event detecting device of  claim 1 , wherein the control module is further configured to calibrate the module timing circuit according to the system timing circuit. 
     
     
         5 . The event detecting device of  claim 1 , wherein the processing circuit consumes less power than the control module. 
     
     
         6 . The event detecting device of  claim 1 , wherein the image-capturing circuit consumes less power when operating in the parking mode than when operating in the driving mode. 
     
     
         7 . The event detecting device of  claim 1 , further comprising a transmitting interface for transmitting the wakeup signal. 
     
     
         8 . An image-recording module, comprising:
 a module timing circuit configured to provide a module clock signal; and   an image-capturing circuit
 receiving the module clock signal in a parking mode; 
 performing a photograph function based on the module clock signal; and 
 receiving a system clock signal external to the image-recording module for performing a second video recording function when a specific event is detected according to images captured using the photograph function; 
   wherein the image-recording module is operated in a driving mode when an event detecting device comprising the image-recording module is powered by an external power supply coupled to the event detecting device, and the image-recording module is operated in the parking mode when the event detecting device is no longer powered by the external power supply.   
     
     
         9 . The image-recording module of  claim 8 , wherein the image-capturing circuit further
 performs a first video recording function in the driving mode when receiving the system clock signal or performs the second video recording function in the parking mode; and   performs the photograph function in the parking mode when not receiving the system clock signal.   
     
     
         10 . An event detecting device, comprising:
 a power supply module configured to provide external power from an external power supply coupled to the event detecting device or provide built-in power from a built-in power supply;   an image-recording module, comprising:
 a module timing circuit configured to provide a module clock signal; 
 an image-capturing circuit
 when receiving a system clock signal external to the image-recording module, performing a first image-capturing function in a driving mode according to the system clock signal; and 
 when not receiving the system clock signal, performing a second image-capturing function in a parking mode according to the module clock signal; and 
 
 a processing circuit enabling the image-capturing circuit for performing a second video recording function in the parking mode when determining that a difference between an image parameter of consecutive photos obtained when the image-capturing circuit performs a photograph function is larger than a threshold value in the parking mode; and 
   a control module configured to send the system clock signal to the image-recording module when the power supply module provides the external power;   wherein the event detecting device is operated in the driving mode when the power supply module provides the external power, and the event detecting device is operated in the parking mode when the power supply module provides the built-in power.   
     
     
         11 . The event detecting device of  claim 10 , wherein the first image-capturing function is a first video recording function. 
     
     
         12 . The event detecting device of  claim 10 , wherein the second image-capturing function is the second video recording function or the photograph function.