Portable security system for outdoor sites

A security system suitable for protection of property within a monitored area from human intruders, the security system comprising:

• a detector for sensing an intrusion within the monitored area and producing a detection signal when intrusion is detected;
• an alarm generator for producing an alarm capable of startling a human intruder;
• an ultrasonic signal generator;
• a controller for activating the ultrasonic signal generator for at least a portion of a predetermined first time period in response to the detection signal from the detector, and for activating the alarm generator at the end of the first time period if the detector is then producing the detection signal;
• and
• a power supply for powering the detector, the alarm generator, the ultrasonic signal generator, and the controller.

A method for protecting property within a monitored area from human intrusion, comprising:

• detecting an intrusion within the monitored area with a detector and producing a detection signal when intrusion is detected;
• generating an ultrasonic signal for at least a portion of a predetermined time period in response to the detection signal from the detector to clear animals sensitive to ultrasound from the monitored area;
• and
• activating an alarm generator capable of startling a human intruder at the end of the predetermined time period if the detector is then producing the detection signal.

A method for protecting property within a monitored area from human intrusion, comprising:

• positioning a plurality of portable security systems around the perimeter of the monitored area, each security system including a detector for sensing an intrusion within a corresponding detection zone and for producing a detection signal when intrusion is detected, an alarm generator for producing an alarm and a controller for activating the alarm generator in response to receiving the detection signal from the detector;
• forming a communication link between the plurality of portable security systems so that the controllers of the security system are capable of communicating with each other;
• operating the detector of each of the security systems until a detection signal is generated by the detector of one of the security systems;
• and
• sending a signal over the communication link from the controller of the security system having the detector that generated the detection signal to the controllers of the other security systems, whereby the controllers of the other security systems become subservient to the controller of the first security system that sent the signal, and the alarm generator of each of the security systems is activated by the controller of each of the security systems.