The subject of the invention is a motion sensing circuit having a plurality of motion sensitive switches connected serially therein and which conduct a quiescent current through the circuit in one stable condition whereas in another stable condition of said switch above a upper limit of the tripping, the quiescent current flow is re-established and, in between the current through the switch is interrupted. In both stable conditions the switch represents a short circuit, that is current flows through the circuit, while between the two stable conditions the current is interrupted and a registering device at the output of the circuit will sense such tripped or alarm condition.
The subject of the invention also covers the provision that the switches according to the present invention employ mercury as the moving contact within the tripping sensitive switch which will perform the connection of the contacts in both the stable conditions. The geometrical shaping of the motion sensing switch is such that the mercury will flow from one stable condition into the other during the tripping quickly and, there between, it provides the geometric shaping for an interruption of the current between the two contacts.
The motion sensing apparatus according to the present invention finds application in automobiles, buildings, and other structures as an alarm device wherein a plurality of switches can be placed at various locations each and, perform the observation of the object assigned independently of each other.