Sensor means or module for determining a displacement or deflection or bending, household appliance and method for determining the weight of an item

A household appliance comprising a cooking hob having glass or ceramic top panel defining at least one cooking zone, at least one sensor positioned underneath said top panel for estimating or determining a weight of an item on the top panel, and a controller operatively coupled to the at least one sensor;

• said at least one sensor comprising:
• a photosensor connected or fixed to a housing or frame part of the household appliance, said photosensor being a reflective type photosensor configured to measure a distance to a reference point or reference area and thereby to detect deflection of said top panel in a range of 0.01 to 0.3 mm as a result of the item being placed on an upper surface of said top panel;
• said reference point or reference area comprising a reflecting surface being a shiny surface of the panel, a surface of a metal evaporation glass, or a surface of a drop of a color or print applied on the panel;
• said photosensor being further configured to transmit to said controller a photosensor signal corresponding to said deflection of the top panel;
• said controller being configured to determine the weight of said item through reference to a lookup table based on said photosensor signal, wherein the photosensor is positioned underneath the panel and/or is a photointerrupter;
• and
• an acceleration sensor configured to detect an acceleration of a panel section, the reference point, or the reference area of said top panel due to deflection thereof as a result of the item being placed on the upper surface of said top panel;
• the acceleration sensor being further configured to transmit to said controller an acceleration signal corresponding to the detected acceleration;
• said controller being configured to calculate or estimate the weight of said item by integrating the detected acceleration, or by integrating a movement of the top panel during said detected acceleration, over time, wherein the acceleration sensor is configured to detect the acceleration during an elastic displacement, deflection, or bending of the panel or the panel section due to placing the item to be weighed on the panel.