Level Sensing in Washing Machines and Dish Washers
Washing machines and dishwashers have smaller reservoirs to hold various fluids that help the user in continuous easy running of these appliances. Washing machines need such reservoirs for holding liquid detergents used in the washing of the clothes, or fabric softener for the protection of the clothes. Dish washers user reservoirs for holding water softeners to reduce the hardness of the incoming water supply to help reduce stains on the dinnerware. A window is usually given behind the door of these appliances, to check the level manually. With time, this window gets stained, and it is difficult to view the exact level. This is where a small foamed magnet on a spindle can be fixed to the reservoir cap, with a reed sensor mounted on the circuitry. When the reservoir reaches a near empty level, the reed sensor signals the processor which lights up an LED on the panel. Special reed sensors can be used to switch line voltages directly without the need for any step down.