Liquid level indicating

An apparatus and method are disclosed to sense the level of a liquid within a volume. The apparatus comprises: an elongated strip to extend into a volume containing a liquid; a series of heaters supported by the strip along the strip, each of the heaters at a different depth within the volume; and a series of temperature sensors supported by the strip along the strip, each of the temperature sensors at a different depth within the volume, wherein the temperature sensors output signals indicative of dissipation of heat from the heaters to indicate a level of the liquid within the volume, wherein the heaters and temperature sensors are arranged in an array of stacks spaced along the length of the strip, each respective stack in the series of stacks comprising a respective heater and a respective temperature sensor that are one over another in a direction perpendicular to the length of the strip. The current invention aims to provide cost-effective liquid level sensing devices.