Patent ID: 8836531

Claim:
An active warning device, applied to a server including a midplane board and at least a control module connected to said midplane board, comprising: at least a reflector, disposed in said corresponding control module; at least a sensor, disposed on said midplane board, corresponding to said reflector, and connected electrically to a multiplexer of said midplane board; and an alarm, disposed on said midplane board, and connected electrically to said multiplexer of said midplane board; where when said control module departs from said midplane board, said sensor transmits energy to said reflector; said reflector reflects said energy; said sensor receives said reflected energy and produces a sensing signal; said sensor transmits said sensing signal to said multiplexer; said multiplexer calculates a distance between said control module and said midplane board according to said sensing signal, and compares said distance with a length of said control module; said multiplexer produces a warning signal according to said distance while said distance is smaller than said length of said control module, and said multiplexer transmits said warning signal to said alarm; and said alarm produces a warning sound according to said warning signal; wherein said step of comparing the distance between said control module and said midplane board with the length of said control module further comprises a step of judging the distance between said control module and said midplane board is greater than the length of said control module, a stop signal is produced and said alarm stops producing said warning sound according to said stop signal.