Container Security Device

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Background: This invention relates generally to monitoring systems, and more particularly, to door status monitoring systems and methods such as, for example, systems and methods for monitoring status of access doors for cargo containers. This invention provides improved shipping container status monitoring systems and methods. In general terms, embodiments of this invention include door status monitor systems arranged to detect tampering events for a shipping container. A door status monitor system can generally include an array of sensors operatively disposed to communicate with a controller. The controller can continually monitor sensors to determine possible tampering events. If tampering events occur, the controller can log the event or transmit tamper signals. Embodiments of the present invention can be used on various types of containers, so it is to be understood that while exemplary embodiments may be discussed with respect to cargo containers, the full scope of the invention is not so limited. The system may be configured to monitor access to and conditional status of a container. Such a system can generally comprise a plurality of door controllers and a controller module. A first door controller module can be disposed in communication with the controller module. The first door controller module can receive a first random generated code from the controller module and store the first random generated code. A second door controller module can be disposed in communication with the controller module. The second door controller module can receive a second random generated code from the controller module and store the second random generated code. The controller module can separately interrogate the first door controller and the second door controller and establish an alarm condition based on one or more signals received from the first door controller and the second door controller. Alarm conditions can be based on errors in receiving at least one of the first random generated code from the first door controller or the second random generated code from the second door controller. Alarm conditions can also be based on a power level of an optical signal received at the controller module from at least one of the first door controller or the second door controller. The invention also encompasses methods, including methods to monitor access to and conditional status of a container. Such methods can generally include providing a main controller module and a pair of door modules, configuring the main controller to conduct two-way communications with the pair of door modules, configuring the main controller to randomly generate a first codeword and a second codeword and to provide the first codeword to one of the door modules and the second codeword to the other door module; and configuring the main controller to interrogate the pair of door modules and to establish an alarm condition based at least partially on at least one of whether the door modules return a provided codeword that matches the first or second codeword and predefined alarm parameters. Methods can also include configuring the main controller to wirelessly communicate with a remote wireless device and to receive data from the wireless device that includes the predefined alarm parameters. Some methods can also include providing the main controller with a memory for storing alarm event data.