Abstract: An aquarium liquid security system is provided. The system includes an aquarium tank, i.e., a plurality of transparent material sheets joined at the sheet edges, and a liquid detection sensor. The sensor is at least partially wrapped around the perimeter, and is electrically responsive to liquid. An alarm interface is connected to the sensor. In one aspect, the sensor includes a pair of electrically conductive ink traces printed on the outside surfaces of the transparent material sheets. In another aspect, the sensor includes a liquid-permeable strip of material, a pair of electrically conductive traces, and a liquid-permeable adhesive attaching the sensor to the perimeter outside surface. Examples of liquid-permeable materials include cardboard, burlap, cotton cloth, synthetic cloth, paper, or cheesecloth. Alternately, the sensors can be formed on the interior surfaces of the aquarium and used for the detection of a low level of water.

Abstract: A liquid-surface detection assembly, a vessel-integral overflow detector, and trans-surface field sensor designs are provided. The detection assembly comprises a trans-surface liquid detection field aligned in a horizontal plane, and a detection signal interface to supply a signal responsive to the detection of liquid surface across the liquid detection field. The trans-surface liquid detection field includes a first set of sensors with horizontal plane mounting interfaces, and the detection signal interface supplies a signal responsive to the measurement of electrical resistance between sensors in the first set. Sensor designs and mounting interfaces specifically tailored for use in a trans-surface field are also presented. Grid, sieve, and tube housing designs are presented that minimize incidental contact with sensor electrodes, but that are able to measure the presence of steady-state liquid surface. These designs also permit a detector to be enabled as a single-station.