Patent ID: 8111383

Claim:
A method for surveillance of a target, comprising the steps of: (a) obtaining a portable device, which includes: (1) a laser range finder operable for measuring distances between the laser range finder and a target, (2) an alarm operable for generating a perceptible signal, and (3) a microcontroller in electrical communication with the laser range finder and the alarm, wherein the microcontroller is configured and arranged to: (A) receive an initial distance value from the laser range finder, (B) receive a subsequent distance measurement value from the laser range finder, (C) compare the initial distance value and the subsequent distance measurement value to obtain a change value, (D) trigger the alarm to generate the signal when the change value is value is within a specified range, (b) statically positioning and operating the device to measure the distance to an object comprising a moveable obstruction to an ingress or egress, and (c) monitoring the generation of any signal by the device indicative of movement of the object to permit ingress or egress.