Device that never leaves a light left on after everyone's left or shuts a light off with any inside.
This device is a solution to a personal pet peeve: people forgetting to switch off lights when they are the last to leave. The device also remedies another pet peeve: motion detecting lights that turn off even if someone is in the room but has not moved in too long - resulting is silly arm waving in the dark. This design builds from my first iteration by incorporating feedback concerning accuracy of ultrasonic sensors, ability to count people side by side, and usability on different switch types.
This device detects the passage of a person inside or outside of the room using time of flight sensors mounted above the doorway, pointing down to the ground. There are two sensors so that directionality is determined. When the count ascends to 1 the light is turned on. When the count descends to 0 the light is turned off. The light switch is turned on or off using a servo motor. The device is enclosed in a wood, laser cut box designed in Rhino.
This device is modular by offering options in type of light switch and doorway width. When the device starts the user has the option of a toggle switch or decora switch. There are corresponding attachments to the device for each type of switch. The next option is the doorway width. One pair of sensors is a zone and a standard doorway uses one zone. A wider doorway uses two zones. This ensures that people walking side by side will not be missed.
Progress Images
Initial prototype sketches
Wire mapping
Testing sensors
Soldered boards
Laser-cut enclosures
Light switch types (strong toggle, toggle, decora)
Final install