The invention concerns a device for manual application of a liquid, particularly for painting, marking, drawing, writing and/or applying make-up to keratinous surfaces, in which the device has a capillary store for the liquid. According to the invention a device for measuring the filling level of the capillary store is provided.

A fluid level detection apparatus for sensing a fluid level of a liquid in within a container, the apparatus including electrically conductive first and second members each having proximal and distal end portions both in an initial circuit state. Also included in the apparatus is control circuitry that is operative to monitor the first and second proximal end portions to produce a primary perceptible output in response to the first and second distal end portions forming an auxiliary circuit state from the initial circuit state, wherein operationally the first and second distal end portions are disposed within the container moving from the initial circuit state to the auxiliary circuit state with a presence of the liquid in the container with the liquid in contact with the first and second distal end portions to ultimately indicate a primary liquid level resulting in the primary perceptible output.

A fluid sensing system includes a sensing element having a positive temperature coefficient of resistance. The system also includes a switch which is switchable between an open position which prevents current from passing and a closed position which permits current to pass. An inductor is connected electrically in series between the switch electric output and the sensing element and a diode is connected electrically in series between the sensing element and the inductor such that an output of the diode is between the switch and the inductor. A hysteretic controller changes the switch from the open position to the closed position when current passing to the sensing element falls to a lower current threshold and changes the switch from the closed position to the open position when current passing to the sensing element rises to an upper current threshold. A voltmeter measures voltage across the sensing element.

A system includes a container having an inner chamber for storing fluid, at least one measuring probe arranged within the chamber and one ground probe arranged within or near a bottom of the chamber. There is at least one impedance electrically connected with a processor which is electrically connected with the at least one measuring probe. A signal generator has a first voltage terminal electrically connected with the at least one impedance and a second voltage terminal electrically connected with the ground probe. When a signal is sent from the signal generator to the measuring probe, an electrochemical reaction occurs at the measuring probe and ground probe and stores a charge if the measuring probe and/or ground probe are immersed in fluid. The processor measures the voltage, current and power of the signal to calculate the resistance and capacitance of the fluid within the container to determine the level of fluid in the container. A method for measuring the level of fluid in the container includes the steps of applying at least one time-varying voltage signal to the one or more measuring probes, creating an electrochemical reaction between the ground probe and each measuring probe, storing energy around each probe that is submerged in fluid, measuring the current and power of the signals, and determining the level of fluid in the container based on the calculated capacitance and resistance of the fluid within the container.

A resistive microelectronic fluid sensor implemented as an integrated voltage divider circuit can sense the presence of a fluid within a fluid reservoir, identify the fluid, and monitor fluid temperature or volume. Such a sensor has biomedical, industrial, and consumer product applications. After fluid detection, the fluid can be expelled from the reservoir and replenished with a fresh supply of fluid. A depression at the bottom of the sample reservoir allows a residual fluid to remain undetected so as not to skew the measurements. Electrodes can sense variations in the resistivity of the fluid, indicating a change in the fluid chemical composition, volume, or temperature. Such fluctuations that can be electrically sensed by the voltage divider circuit can be used as a thermal actuator to trigger ejection of all or part of the fluid sample.

A fluid characteristic sensing device has a projection. The fluid characteristic sensing device receives current pulses and directs the received current pulses through the projection. The received and directed current pulses enable determination of a resistance of the projection and a rate of change of temperature.

A fluid sensing system includes a sensing element having a positive temperature coefficient of resistance. The system also includes a switch which is switchable between an open position which prevents current from passing and a closed position which permits current to pass. An inductor is connected electrically in series between the switch electric output and the sensing element and a diode is connected electrically in series between the sensing element and the inductor such that an output of the diode is between the switch and the inductor. A hysteretic controller changes the switch from the open position to the closed position when current passing to the sensing element falls to a lower current threshold and changes the switch from the closed position to the open position when current passing to the sensing element rises to an upper current threshold. A voltmeter measures voltage across the sensing element.

A fluid aspiration probe apparatus for automatic fluid testing equipment includes a pair of electrodes mounted on a distal probe tip. The electrodes are coupled to an impedance measurement apparatus via conductive pathways along the probe. The impedance measurements and probe tip height are monitored as the probe tip is lowered into a fluid sample. Boundaries between layers of fluid in the container are detected by recognizing sudden changes in the impedance measurements and heights of the boundaries are determined by tracking the position of probe tip when the sudden changes of impedance occur.

A Christmas tree fire extinguishing system is provided, wherein an automatically initiated fire extinguishing agent is contained within a housing below the tree and a plurality of smoke and heat sensors communicate to a control unit. The control unit controls the trigger and interprets the sensor signals, while also sending signals to a communications system upon a fire event to notify the homeowner and/or the local fire authorities. In combination with the fire extinguishing agent, the system can monitor the tree and alert property authorities in the event of a fire to prevent home fires and major property damage. Also provided is an audible fire alert for those in the home, wherein a sound generator is energized if smoke or fire is detected to warn those in the immediate vicinity.

A liquid level detection system for determining a liquid level includes a level sensor configured to be at least partially disposed in a liquid storage vessel and exposed to liquid. A first optoelectronic interface is operatively connected to the level sensor for providing power thereto. A second optoelectronic interface is operatively connected to the first optoelectronic interface. A fiber optic cable optically connects the first optoelectronic interface to the second optoelectronic interface to provide photonic power to the first optoelectronic interface and to transmit data from the first optoelectronic interface to the second optoelectronic interface.