Door MonitorBy Thingvold, Craig; Johnson, Toby; Glower, Jacob; NSF 2007 Engineering Senior Design Projects to Aid Persons With Disabilities, pp. 82-83
Publication Date: 2010
Description of a door monitor designed for a facility for children with disabilities that faced the risk of having some children leaving the premises unsupervised. Developed at North Dakota State University’s Department of Electrical and Computer Engineering, the door monitor consists of a transmitter and a receiver. The 3-by-two-by-two inch transmitter attaches to the child or a wheelchair and has three main components: a 3 volt power supply, a processor, and a radio frequency transmitter. The main components of the receiver include a door switch, an alarm and alarm reset, a processor, and a 5 volt power supply. The receiver is connected to a door switch that tells it whether the door is open or closed. A piezoelectric speaker mounted to the top of the receiver is used as the alarm. When the door is opened, the door switch tells the processor to search for a transmitter. The processor actuates the alarm once the receiver sees the transmitter. Once the alarm is sounded, the reset must be pressed to silence the alarm. The processor will then wait ten seconds before it starts searching for a transmitter again. The system is low cost and the design is simple enough to allow the facility to replicate the transmitters.
Published by: Creative Learning Press, Inc. (Website:http://www.creativelearningpress.com)
Link to text: http://nsf-pad.bme.uconn.edu/2007/Chapter8,%20North%20Dakota%20State%20University.pdf