A Maryland woman has created a device to alert people with hearing loss when someone is turning a door knob. Janet Williams' Door Knob Alarm sends out a piercing tone and a series of red lights when the door knob is turned from either side. The donut shaped alarm will fit on any door and detects movement.
Monday, July 6, 2009
The Door Knob Alarm
A Maryland woman has created a device to alert people with hearing loss when someone is turning a door knob. Janet Williams' Door Knob Alarm sends out a piercing tone and a series of red lights when the door knob is turned from either side. The donut shaped alarm will fit on any door and detects movement.
