A hazard warning system for warning personnel of potential peril within a
specific warning zone, the system including a variable, ultrasonic, and/or
infra-red directional transmitter directed to focus on and around a
specific hazard and a receiver having both audio and visual warning
indicators worn by the worker. Workers outside the warning zone or field
not receiving the warning are therefore not immunized by visual and
audible signals which are not pertinent to their safety. The warning
system further utilizes distance measuring circuitry to automatically
determine the distance from the transmitter located on an evaluated crane
boom to ground or deck. The distance measurement is then micro processed
to maintain a prescribed infra-red field around a suspended object
regardless of the boom height. A further embodiment utilizes the
technology for a portable signal generator apparatus for attachment to a
moving load or vehicle, the warning zone or field may be directed and
varied in size and range.