Abstract: A portable sensing device may be deployed for determining at least one stability metric of a vessel. The sensing device may include one or more motion sensors for sensing motion of the vessel, one or more freeboard sensors for determining a freeboard of the vessel, and a computing system for processing motion data from the one or more motion sensors and freeboard data from the one or more freeboard sensors to determine the at least one stability metric. The computing system may be programmed to transform the motion data from time domain motion data to frequency domain motion data and process the frequency domain motion data to determine the at least one stability metric of the vessel and the freeboard of the vessel.

Abstract: A system for orienting a marine vessel is provided. The system includes marine propulsion devices, a gyroscopic stabilizer system, and a controller operably coupled to the marine propulsion devices and the gyroscopic stabilization system. The controller is configured to control operation of the marine propulsion devices to minimize a control torque output of the gyroscopic stabilizer system while maintaining the marine vessel in a selected global position and/or heading.

Abstract: A level meter includes light emission segments forming an emission region, a register portion to register a default emission condition and an emission-condition specified value, and a control portion. The control portion controls the light emission so that the emission region spreads in an emission proceeding direction according to an increase in numerical quantity to be expressed. An emission-condition specified value indicates a command to apply a predetermined specified emission condition concerning a subsequent segment positioned on a more upstream side than a foremost segment positioned on a most downstream side in the emission proceeding direction. The control portion allows all the light emission segments forming the emission region to emit light based on the default emission condition, and the control portion allows the foremost segment to emit light based on the default emission condition whereas allowing the subsequent segment to emit light based on the specified emission condition.

Abstract: A water submersion detection system that may include a buoyant device having a conductive surface, and a housing enclosing the buoyant device and having conductive elements. The conductive elements may include a first set of one or more nonadjacent conductive elements that are electrically connected, and a second set of one or more nonadjacent conductive elements that are electrically connected. The system may include a submersion alert device that activates responsive to the buoyant device contacting the housing.

Abstract: In an embodiment a switching device includes at least one stationary contact, a movable contact, an armature, a first permanent magnet, a second permanent magnet and a magnetic switch, wherein the movable contact is movable by the armature, wherein the first permanent magnet is attached to the armature, and wherein the second permanent magnet is arranged in a fixed position relative to the magnetic switch.

Abstract: A marine information integrated online monitoring buoy system comprises a buoy body. Specifically, a protection apparatus is disposed outside the buoy body. A bearing is disposed outside the buoy body, convex strips are arranged around a bearing outer ring, two floating rings are disposed outside the bearing outer ring with a certain spacing distance from the outer ring and arranged vertically, a protective cylinder is arranged between the upper and lower floating rings in a surrounding manner and is rotatable relative to the floating rings, and then a protective retaining ring is sleeved outside the protective cylinder and is rotatable relative to the protective cylinder. The longest end of a protective retainer is abutted against the bearing outer ring during rotation of the outer side of the protective retaining ring, and a friction block is disposed on the protective retainer.

Abstract: A method for operating a laundry machine having a rotatable drum a tub enclosing said drum; a water supply; a control unit a laundry treatment agent dispensing device configured to hold and deliver at least one of a laundry detergent and a laundry softener; and a control system configured to provide a softener signal that alternately assumes a first value indicating that no laundry softener will be delivered, and a second value indicating that laundry softener will be delivered. The method comprises: performing a washing phase in which detergent is delivered into the tub; and performing a number of rinsing phases wherein detergent from the washing phase is removed using water from said water supply apparatus, wherein the control unit sets the number of rinsing phases according to whether the softener signal assumes the first value or the second value.

Abstract: A field configurable autonomous vehicle includes modular elements and attachable components. The vehicle can be assembled from these modular elements and components to meet desired mission and performance characteristics without the need to purchase specially designed vehicles for each mission. The vehicle can include a mechanisms that magnetically attach and release configurable elements from the vehicle.

Abstract: There are described systems and methods for annunciating engine lubricating fluid level. The system comprises a first fluid level sensor for a first engine; a first low-level detector coupled to the first fluid level sensor; a first low-level indicator coupled to the first low-level detector for annunciating a fluid level of the first engine below a minimum operating level; and an annunciation and display system coupled to the first low-level detector and configured for performing non-critical lubricant-related functions. The first fluid level sensor, the first low-level detector, and the first low-level indicator are composed of first components having a critical level of reliability, the annunciation and display system is composed of second components having a non-critical level of reliability.

Abstract: An engine oil dipstick for monitoring an internal combustion engine comprises a processor and a sensor module. The sensor module is configured to sense a characteristic of the internal combustion engine and to output data representative of the sensed characteristic to the processor. The engine oil dipstick is configured to provide a housing for the processor. The processor is configured to determine a value representative of the firing frequency of the internal combustion engine based on the output data.

Abstract: A tank storage measurement device. The tank storage measurement device includes a display screen. The tank storage measurement device is configured to display on the display screen an image of a storage tank. The tank storage measurement device is additionally configured to use the image of the storage tank to identify boundaries of the storage tank and identify a qualitative level of a substance in the storage tank. The tank storage measurement device is additionally configured to generate a quantitative representation of the level of the substance using the identified boundaries and identified qualitative level of the substance. The tank storage measurement device is additionally configured to display on the display screen the generated quantitative representation of the level of the substance.

Abstract: A tank fill control apparatus comprising: a tank-installed switch, including: a tubular body including an upper end, a lower end, and an annular mounting flange on an outer surface between the upper end and the lower end; a liquid level sensor including a detector, a float in and moveable along a length of the lower end and a rod connecting the float to the detector, the liquid level sensor configured to sense a liquid level relative to the lower end and further configured to generate a signal when at least a maximum selected liquid level is sensed; and a control unit in communication with the tank-installed switch including: a liquid level monitoring function for receiving the signal from the liquid level sensor; and a control function for generating at least one of (i) an alert signal indicating that the maximum selected liquid level is sensed and (ii) a valve control to modify a fill operation from a tank fill system.

Abstract: An item may be outfitted with a cartridge for varying a net density of the item and deposited in a body of liquid for storage. The cartridge may cause a net density of the item to exceed a density of the liquid, or to fall below the density of the liquid, and to descend or ascend within the liquid, as desired. The cartridge may also cause a net density of the item to equal the density of the liquid, and thus remain at a constant depth. The cartridge may be configured to receive acoustic signals or other forms of instructions for varying a net density of the item, and may send acoustic signals or other messages identifying a depth or position of the item. The cartridge may thus enable an item to be stored at any depth within the liquid, and be retrieved upon demand.

Abstract: A liquid characteristic analyzing apparatus may include a sensor part to bring a sensor surface into contact with the liquid and outputs an electrical signal; a transmission part to convert the electrical signal to an electromagnetic wave signal or a sound wave signal and wirelessly output the electromagnetic wave signal or the sound wave signal; a containing body that exposes the sensor surface, contains the sensor part and the transmission part, and prevents the liquid from intruding into the inside, the containing body arranged in the container and immersed in the liquid; and close contact structures to bring a passing portion for the electromagnetic wave signal or the sound wave signal into substantially close contact with an inner wall of the container. The close contact structures may include a first magnetic part that is provided in the containing body and a second magnetic part that is arranged outside the container.

Abstract: An apparatus is provided for measuring level of a process fluid in a container opening. The apparatus includes a remote seal configured to be inserted into the container through an opening and configured to receive a pressure related to the level of process fluid in the container. A capillary tube filled with a fill fluid extends from the remote seal to the opening and is configured to convey the pressure therebetween. A pressure sensor coupled to the capillary tube senses the pressure from the capillary tube and responsively determines the level of the process fluid in the container. The remote seal includes a bellows portion arranged to isolate the process fluid from the fill fluid in the capillary tube and convey the pressure therebetween.

Abstract: A system and method for detecting phase separation in storage tanks is provided. At least one float has a density calibrated to detect a density differential among surrounding fluids. The float is buoyant on a relatively more dense lower layer of fluid such as phase separated fuel or pure water, while remaining submerged in a relatively less dense upper layer of fluid such as a gasoline/ethanol blend. A detection device sends a signal when the float rises or falls above or below a preset acceptable level.

Abstract: A fueling environment is equipped with leak detection probes and liquid level probes. Each of the probes is associated with a wireless transceiver. The wireless transceivers send probe data to a site communicator wireless transceiver. To ensure that the site communicator receives the probe data, repeaters are used within the fueling environment. The repeaters receive the probe data, and some period of time after the sensor transceivers stop transmitting, the repeaters retransmit the probe data to the site communicator. The site communicator discards duplicative information and processes the probe data as needed.

Abstract: A portable, self-contained flood alarm which alleviates the shortcomings of the alarms of the prior art and offers an easy-to-use and reliable flood and water level alarm which will adequately warn users of potential flood conditions and possibly save their personal belongings, equipment and lives.

Abstract: A fluid level measurement apparatus supports multiple fluid level sensors of different types, each of which detects a level of fluid and produces an output indicative of the detected fluid level in a different way. The fluid level measurement apparatus is connected to any one of the supported fluid level sensors to measure the fluid level. The fluid level measurement apparatus includes a calculation circuit, multiple output circuits, a determination circuit, and a selection circuit. The calculation circuit calculates the fluid level from a detection voltage. Each output circuit generates the detection voltage based on the output of a corresponding fluid level sensor. The determination circuit determines the connected fluid level sensor. The selection circuit selects the output circuit corresponding to the determined fluid level sensor and allows the calculation circuit to obtain the detection voltage generated by the selected output circuit.

Abstract: A fuel gauge system has a fuel gauge unit, a processing unit, display units, input units, and a GPS navigation system unit with means to connect to other connections and which, by audio and visual aids, informs and alerts an operator of a vehicle of the amount of fuel remaining and range and which allows the operator to manipulate and select and alter the levels, the volume and frequency intervals at which the alerts are sounded, emitted and displayed.

Abstract: A method of controlling an ebb and flow watering system utilizing existing hardware commonly used in ebb and flow systems including float switches, water pumps, electromechanical timers, reservoir, control bucket, flood lines, indicator LEDs and plant containers such that the filling and draining of the control bucket is improved by accommodating for hydraulic delays, flood line restrictions, and pump limitations, while further providing constant monitoring for leaks or float switch failure, and shutting off the pumps if the same are determined.

Abstract: A water level detection device includes a case, a detection assembly, and a latching ring secured to the case. The detection assembly includes a warning module, a micro switch, a cable, and a floater. The cable is inserted through the latching ring and divided to a first section connected to the micro switch and a second section connected to the floater. When a water level is in an upper limit or a lower limit, the second section is tight, and an angle is defined between the second section and the first section. When the water level is between the upper and the lower limit, the second section is loose. When the water level is over the upper limit or under the lower limit, the floater pulls the first section via the second section to trigger the micro switch to alarm the warning module.

Abstract: A gas flow warning alarm device to produce an alarm indication when the gas flow rate in a pressurized gas system violates at least one predetermined limit. The alarm device includes a gas flow sensing and error signaling subassembly to generate an error signal upon sensing a violative gas flow rate, and an indicator subassembly activatable by an error signal to produce an alarm indication. The gas flow warning alarm device responds both to the depletion of a pressurized gas reservoir and to blockages and disconnections in a gas line downstream of a regulator. A method for detecting gas flow malfunctions in a pressurized gas system. A reservoir changing device to open a filled reserve reservoir of gas to a pressurized gas system upon receiving an alarm indication that pressure in a primary gas reservoir has fallen below a predetermined limit.

Abstract: Disclosed are integral and/or portable, easy-to-install apparatuses for detecting and containing fluid leaked or otherwise discharged from a fluid-filled device and for facilitating testing and maintenance of the apparatus and fluid-filled devices. In one aspect of the disclosed invention, upon sensing a fluid discharge, the apparatus activates audible and/or visual alarms and directs the discharged fluid to a predetermined drainage area to prevent damage to areas surrounding the fluid-filled device. In another aspect of the present invention, no plumbing or electrical wiring is required to install the apparatus, thereby allowing an unskilled individual to easily and inexpensively install the apparatus. In yet another aspect of the present invention, the apparatus may be easily located since it is not dependent on gravity or a drainage pipe for discharge of the fluid.

Abstract: A contact is provided for a fluid level detection apparatus. The contact includes a contact support spring for rotating in response to a change in fluid level. The contact support spring includes a cantilevered spring arm having a proximal end to be fixed to a holder and a free end, and a contact support which is provided at the free end. First and second contacts are attached to the contact support in first and second positions, respectively, the first position being set at one end opposite to an end at which the second position is set. The joining position of the contact support and cantilevered spring arm is set so that a pressing load applied to the first and second contacts on the contact support by the flexure displacement of the contact support spring falls within a predetermined range.

Abstract: A modular device for determining attributes of a substance stored in a container having a sensing module, a transmitter module and a power source module. The sensing module is capable of sensing attributes of a substance and providing an output. The transmitter module is configured to transmit an output of the at least one sensing module when operably coupled to the sensing module. The power source module is capable of being operably connected to the sensor module and the transmitter module to power the sensor module and the transmitter module.

Abstract: A wastewater holding tank sensor probe for use in determining the presence of a conductive liquid held within a wastewater holding tank in a recreational vehicle is disclosed. The probe is less sensitive to the presence of conductive residue as a result of an improved geometry and/or choice of materials that reduce the leakage currents between the probe tip and the sensor probe attachment surface, typically the wall of the tank. This reduction in sensitivity to conductive residue buildup can be measured by a geometrically determined resistivity factor between the probe tip and the mounting surface of the probe. The reduction in sensitivity can also be measured by the length of the path through the conductive residue between the probe tip and the mounting surface of the probe. A variety of geometries and material choices to reduce the sensitivity of electrical conductance based sensor probes to conductive residue are disclosed.

Abstract: A system for monitoring a level of product in a tank to detect one of a delivery and a drain operation is provided. The system comprises a monitor and a data center. The monitor is operably coupled to the tank and adapted to detect the level of product in the tank at a first rate and at a second rate. The data center is in communication with the monitor and adapted to receive a user inputtable threshold level of change. The monitor detects the level of product in the tank at the first rate until the threshold level of change is detected. Thereafter, the monitor detects the level of product in the tank at the second rate. The data center generates an alarm signal to indicate that one of the delivery and the drain has occurred.

Abstract: A dewatering system includes a selective calibrating sensor circuit configured to receive sensor readings from an electronic sensor, to determine if the electronic sensor is immersed in water, to allow a user to adjust a pump down time in the field, and to generate a control output signal accordingly. The selective calibrating sensor circuit periodically performs a self-calibration when the electronic sensor is not immersed in water to cancel the effect of potential contaminants deposited on the electronic sensor over its operating life. The selective calibrating sensor circuit inhibits calibration when the electronic sensor is immersed in water. In some applications with multiple electronic sensors, the selective calibrating sensor circuit disconnects from one of the electronic sensors before performing the self-calibration.

Abstract: An inexpensive and simple-to-operate ice safety device is provided for deployment in a body of water. Once deployed, the ice safety device can be activated to check whether ice has formed to a predetermined thickness around the ice safety device. If ice has not formed to the predetermined thickness, the ice safety device indicates an unsafe condition. The ice safety device can be moored to a fixed location.

Abstract: A signal transmitter for a filling level sensor has two sliding contacts which are manufactured integrally with a holder and with spring elements. This leads to the manufacturing costs of the signal transmitter being particularly low. The sliding contacts are arranged on spring tongues and are connected to one another via a link. The spring tongues and the spring elements are therefore arranged in a row and allow the sliding contacts to be prestressed particularly uniformly against sliding tracks of the signal transmitter.

Abstract: In certain embodiments, a multi-channel capacitive sensor for measuring capacitances of sense electrodes to a system reference potential comprises a sample capacitor having first and second terminals. The sensor comprises a first diode having a first terminal coupled to the second terminal of the sample capacitor and a second terminal coupled to a first sense electrode, and comprises a second diode having a first terminal coupled to the second terminal of the sample capacitor and a second terminal coupled to a second sense electrode. A control circuit is operable to apply a drive signal to the first terminal of the sample capacitor and apply a bias signal to the respective second terminals of at least one of the first and second diodes so as to selectively prevent the at least one of the first and second diodes from conducting the drive signal to respectively connected sense electrodes.

Abstract: Disclosed is a floating sensor system having a casing that encloses a microcontroller. The microcontroller includes a digital processor and a non-volatile memory. The casing also encloses a data bus that connects the microcontroller to an external environment sensor, an RF transceiver, and a battery. The non-volatile memory includes a history file that maintains a record of events sensed by the external environment sensors. The digital processor is configured to establish a pattern of expected external environmental behavior based on the record of events. The digital processor is also configured to emit a signal through the RF transceiver from the system when an unexpected event occurs.

Abstract: A tank level alarm system in which all of the electrical components are located in a sealed housing above the tank's upper surface. There is no direct electrical connection between the tank liquid level detector within the tank interior and the alarm electrical components in the housing. A magnetic switch opens and closes based upon the proximity of a magnet mounted to a vertical rod to which a float is attached within the tank. The magnetic switch is positioned electronically in series with a battery and then in parallel with each of a plurality of alarm devices which in the preferred embodiment include a flashing light, an audio generator and a transmitter. When the tank's liquid level is below a selected maximum “safe” level, the magnet mounted to the upper end of a vertical rod is separated from the magnetic switch by a sufficient distance to keep the switch in its “open” state.

Abstract: Apparatus and methods for making glass are provided. The apparatus comprise a first glass melt station and a standpipe. The standpipe includes a first end portion in fluid communication with the first glass melt station. The standpipe further includes a gravity trap that is configured to inhibit formed impurities from traveling from at least a portion of the standpipe through the first end portion of the standpipe. The methods comprise the steps of providing the first glass melt station with glass melt, sensing a condition of a quantity of glass melt within the standpipe, and inhibiting formed impurities from traveling from at least a portion of the standpipe through the first end portion of the standpipe.

Abstract: An inductive liquid-level sensor employs a central shaft supporting multiple independent electrical loops that may be interrogated to detect the proximity of the conductive element in the float rising and falling with changes in liquid height outside of the shaft.

Abstract: Disclosed are portable, easy-to-install apparatuses for detecting and containing fluid leaked or otherwise discharged from a fluid-filled device and for facilitating testing and maintenance of the apparatus and fluid-filled devices. In one aspect of the disclosed invention, upon sensing a fluid discharge, the apparatus activates audible and/or visual alarms and directs the discharged fluid to a predetermined drainage area to prevent damage to areas surrounding the fluid-filled device. In another aspect of the present invention, no plumbing or electrical wiring is required to install the apparatus, thereby allowing an unskilled individual to easily and inexpensively install the apparatus. In yet another aspect of the present invention, the apparatus may be easily located since it is not dependent on gravity or a drainage pipe for discharge of the fluid. Furthermore, the apparatus optionally includes an integral leveling mechanism to accommodate leveling of the apparatus when placed on uneven surfaces.

Abstract: A liquid level detecting apparatus includes a liquid level sensor of a variable resistance type which includes a sliding contact and a resistor, and which detects a resistance change corresponding to a change of a liquid level of a liquid in a tank and outputs a detection signal based on the change of the liquid level when the liquid level sensor is energized and a controlling unit which controls to supply energization pulses periodically to the liquid level sensor, and controls a displaying portion to display a remaining amount of the liquid in the tank, on the basis of the detection signal output from the liquid level sensor. The controlling unit changes a number of the energization pulses supplied to the liquid level sensor in a predetermined time, on the basis of the detection signal output from the liquid level sensor.

Abstract: A system and method for detecting phase separation in storage tanks is provided. At least one float has a density calibrated to detect a density differential among surrounding fluids. The float is buoyant on a relatively more dense lower layer of fluid such as phase separated fuel or pure water, while remaining submerged in a relatively less dense upper layer of fluid such as a gasoline/ethanol blend. A detection device sends a signal when the float rises or falls above or below a preset acceptable level.

Abstract: An alarm system is provided for generating an alert when a water-powered sump pump is activated and water is being used by the water-powered sump pump. The alarm system includes a water sensor for detecting if water within a sump reaches the sensor and a housing for containing sensor electronics, wherein the water sensor is supported by the housing. In addition, a clamp is attached to the housing for releasably attaching the housing to a pipe such that the alarm system may be positioned to alert a user when water-powered sump pump is activated.

Abstract: A liquid level warning device with a separate audible alarm is disposed in a liquid tank for indicating the amount of liquid in the tank. The device also includes a plurality of float switches disposed at pre-selected levels within the tank and a plurality of LED's for indicating the level of liquid in the tank. A separate audible alarm independent of the visual indicators sounds an alarm when the tank is at a pre-selected level. A float switch is also disclosed.

Abstract: Provided is an apparatus for detecting a change in a specific gravity of a fluid surrounding the apparatus wherein the fluid moves upwardly and downwardly with respect to the apparatus. The apparatus includes a housing having a top and a plurality of openings for allowing the fluid to enter the housing. A first floatation device is provided having a first specific gravity and being located within the housing. The first floatation device includes a magnet. A second floatation device is provided having a second specific gravity and located within the housing adjacent said first floatation device. The said second floatation device includes a magnet aligned to have the same polarity as the magnet of the first floatation device. A switch fixedly attached to said top, the switch having an open state and a closed state where when one of said magnets is in proximity to the switch, the switch is in a closed state and wherein when both of said magnets are in proximity to said switch, the switch is in an open state.

Abstract: An oil-level detection system for an engine-powered product includes a dipstick designed to be received within a crankcase. The system further includes a detector attached to the dipstick, where the detector is designed to sense, from within the crankcase, a level of oil within the crankcase. The system also includes a display in communication with the detector. The display identifies information to a user related to the level of oil within the crankcase, without the user opening the crankcase.

Abstract: According to one example embodiment, an apparatus may include a chamber, a flotation device inside the chamber, a magnetic sensor circuit, a timing circuit, and a switch circuit. The chamber may be configured to receive water through a first opening and allow water to exit through a second opening. The chamber may also be configured to prevent water from exiting the chamber other than through the first opening or the second opening. The flotation device may include a magnetic material. The magnetic sensor circuit may be configured to determine whether the flotation device is in proximity with a top portion of the chamber. The magnetic sensor circuit may be configured to output a water level signal to a timing circuit based on the determining. The timing circuit may be configured to output an alarm signal to a switch circuit based on the water level signal continually indicating a low water level for a predetermined period of time.

Abstract: A low fluid sensor for an internal combustion engine. The sensor includes a base with helically threaded post and a float slidably mounted on the post. The float rotates about the post as it moves longitudinally along it. In the preferred embodiment, eccentric mounting of the assembly along with its lobe shape act in concert with the pitch of the screw threads and fluid viscosity to dampen the buoyant movement of the float against fluid turbulence. At a predetermined level a latch spring on the float contacts an ignition circuit terminal and grounds the engine ignition circuit. A catch holds the float at the pre-determined level, preventing engine starting, so that the sensor may only be reset by addition of fluid and re-insertion of the dipstick.

Abstract: A fluid-level sensing device that uses the interaction of a first magnet attached to the distal end of an external micro switch arm and a second magnet positioned within the distal end of a pivoting float body to close a circuit within the micro switch and create a shut-off signal to stop fluid production. A single housing holds the micro switch and float body, wherein magnetic forces acting through the housing wall between them and other magnet-positioning materials that separate the two magnets cause signal production. After float body deployment, manual reset of the float body is accomplished via its lever-like distal end. The main body of the micro switch, which it is snap-fit into a fixed position within the upper housing chamber for use, is entirely encapsulated in waterproof material to protect it from corrosion. Alternative ways for quick mounting of the housing to a fluid-collecting pan are contemplated.

Abstract: An oil level detection device for an internal combustion engine, which comprises: a housing permitting entry therein of oil; a float provided within the housing and vertically movable with the oil entered in the housing; a switch for performing switching operation in response to the vertical movement of the float within the housing; protrusions provided, on the upper surface of the float, for preventing the float from sticking to the ceiling of the housing due to viscosity of the oil; and protrusions provided, on the bottom of the housing, for preventing the float from sticking to the bottom of the housing due to viscosity of the oil.

Abstract: Disclosed is a method and device for testing the measuring value of at least one filling level sensor arranged in a fuel tank. A plurality of measurements are taken by the filling level sensors and are each compared with a physical variable to determine whether the measurements are plausible. If, based on the comparison, the measurements from the sensors are not plausible, a warning signal is fed to a warning device and a warning information item is triggered by the warning device.

Abstract: A liquid level warning device with a separate audible alarm is disposed in a liquid tank for indicating the amount of liquid in the tank. The device also includes a plurality of float switches disposed at pre-selected levels within the tank and a plurality of LED's for indicating the level of liquid in the tank. A separate audible alarm independent of the visual indicators sounds an alarm when the tank is at a pre-selected level. A float switch is also disclosed.

Abstract: A warning device against blocking of filter material for an aquarium, it mainly has a receiving case having therein a battery chamber for receiving at least a battery, and having a triggering switch electrically connecting with an indicating lamp installed in the receiving case; and the warning device has a detector which has a link mechanism, one end of the link mechanism is connected with the triggering switch, the other end is provided with a float bowl extending into the filter tank of the aquarium to detect the level of water. When in blocking, the water level rises to raise the float bowl to actuate the triggering switch to turn on the indicating lamp, thus a warning effect is obtained.