A device for monitoring the level or amount of a material within a container is provided. The device includes a detection mechanism that can be a direct detection mechanism or an indirect detection mechanism. When the detection mechanism senses an upper level of the substance in the container that is below a predetermined lower limit for the substance, the mechanism operates an alarm mechanism to emit an alarm to alert an individual to the low level of the substance within the container. The alarm can wirelessly communicate a salt level state to a wireless network or a device on a wireless network that can transmit the status through the Internet to any remote location. In one aspect, the alarm can be sent on a mesh network with a device that can transmit the status and other conditions through the Internet and to an application executing on a mobile device.

A system including a float ball, a pole, a sleeve, an indicator disk, and a dynamo circuit provides information regarding the water level in a tank, and whether fluid is flowing into the tank. The pole slides within the sleeve, through a slab above the tank. A first end of the pole is supported by the float ball, which floats within the tank, while the second end of the pole is located above the slab and supports the indicator disk. A user can detect the water level in the tank based on the height of the indicator disk. A user can also detect whether water is flowing into the tank. The dynamo circuit activates an LED located on the indicator disk when water is flowing into the tank.

A system including a float ball, a pole, a sleeve, an indicator disk, and a dynamo circuit provides information regarding the water level in a tank, and whether fluid is flowing into the tank. The pole slides within the sleeve, through a slab above the tank. A first end of the pole is supported by the float ball, which floats within the tank, while the second end of the pole is located above the slab and supports the indicator disk. A user can detect the water level in the tank based on the height of the indicator disk. A user can also detect whether water is flowing into the tank. The dynamo circuit activates an LED located on the indicator disk when water is flowing into the tank.

A liquid level sensor 1 comprises a sleeve 2 disposed so as to extend in the vertical direction, a float 3 configured so as to move along said sleeve according to fluctuation of liquid level, a resistor string 4, a plurality of grounding means 5 disposed inside the sleeve 2 and a liquid level signal output means 6 to take out an electric signal detected between a positive electrode side end part 4a and a junction part grounded by the grounding means 5 as a liquid level signal that is a signal corresponding to the liquid level, and further comprises a warning signal output means 7 to output a warning signal when the float 3 is located within a predetermined distance from a warning position that is a predetermined position within a movable range of the float 3. Thereby, a compact and reliable liquid level sensor is realized.

A liquid level sensor 1 comprises a sleeve 2 disposed so as to extend in the vertical direction, a float 3 configured so as to move along said sleeve according to fluctuation of liquid level, a resistor string 4, a plurality of grounding means 5 disposed inside the sleeve 2 and a liquid level signal output means 6 to take out an electric signal detected between a positive electrode side end part 4a and a junction part grounded by the grounding means 5 as a liquid level signal that is a signal corresponding to the liquid level, and further comprises a warning signal output means 7 to output a warning signal when the float 3 is located within a predetermined distance from a warning position that is a predetermined position within a movable range of the float 3. Thereby, a compact and reliable liquid level sensor is realized.

An overflow detection system for a grease trap or other receptacle is provided. The overflow detection system includes an overflow sensor. The overflow sensor can include a switch and a processor. The switch can include a float configured to float in a fluid in the receptacle, a surface that is separate from the float, and a resilient member coupled between the float and the surface. The switch can generate a signal in response to the float being within a predefined distance of (e.g., contacting) the surface. The processor can receive the signal from the switch and, in response, transmit a notification to a user device that is remote from the receptacle. The notification can indicate a high fluid level in the receptacle.

A sensor circuit is provided, including a float sensor and a refrigerant sensor. The float sensor includes a float housing a float, and a switch. The float housing has an opening on a first side wall and can contain liquid that flows into and out of the float housing through the opening. The float is in the float housing and rises or falls based on a level of liquid in the float housing. The switch is connected to the float and transmits a signal when the liquid in the float housing rises to a predetermined height. The refrigerant sensor circuit is connected to the float sensor, includes a refrigerant sensor, and detects a level of refrigerant in second air formed at least in part from first air in the float housing. The refrigerant pipe is connected to a second wall of the float housing fully above the predetermined height.

A sensor circuit is provided, including a float sensor and a refrigerant sensor. The float sensor includes a float housing a float, and a switch. The float housing has an opening on a first side wall and can contain liquid that flows into and out of the float housing through the opening. The float is in the float housing and rises or falls based on a level of liquid in the float housing. The switch is connected to the float and transmits a signal when the liquid in the float housing rises to a predetermined height. The refrigerant sensor circuit is connected to the float sensor, includes a refrigerant sensor, and detects a level of refrigerant in second air formed at least in part from first air in the float housing. The refrigerant pipe is connected to a second wall of the float housing fully above the predetermined height.

This disclosure includes systems and methods for testing a vehicle's fuel system. Some systems have a gauge configured to be mounted to a vehicle having a compressed gas fuel system including a compressed gas fuel tank, the gauge having a user interface configured to display fuel pressure within the fuel tank and receive user input to initiate diagnostic testing of the fuel system, and one or more processors configured to, in response to the user input, actuate one or more components of the fuel system, including a solenoid and/or a relay, and display, on the user interface, diagnostic information associated with the actuated one or more components.