Passive sensors for automatic faucets and bathroom flushers

A system including optical sensor for controlling a flow valve of an electronic faucet or bathroom flusher, comprising:

• a flow valve constructed to control water flow;
• an optical element including a slit located at an optical input port and arranged to partially define a detection field having a selected size and orientation that eliminate invalid targets;
• a light detector optically coupled to said optical element and said input port, said light detector being constructed to detect ambient light;
• and
• a control circuit for controlling opening and closing of said flow valve, said control circuit being constructed to receive periodically signal from said light detector corresponding to the detected ambient light and to control said opening and closing by executing a detection algorithm employing detection of increases and decreases of said ambient light due to the presence of a user within said detection field for several time intervals and background level of said ambient light.

A system including optical sensor for controlling a flow valve of an electronic faucet or bathroom flusher, comprising:

• a flow valve constructed to control water flow;
• an optical element including an optical filter located at an optical input port and arranged to partially define a detection field having a selected size and orientation that eliminate invalid targets;
• a light detector optically coupled to said optical element and said input port, said light detector being constructed to detect ambient light;
• and
• a control circuit for controlling opening and closing of said flow valve, said control circuit being constructed to receive periodically signal from said light detector corresponding to the detected ambient light and to control said opening and closing by executing a detection algorithm employing detection of increases and decreases of said ambient light due to the presence of a user within said detection field for several time intervals and background level of said ambient light.