Modular system for monitoring the presence of a person using a variety of sensing devices

• US 20020070866A1
• Filed: 10/02/2001
• Published: 06/13/2002
• Est. Priority Date: 09/04/1996
• Status: Active Grant

• Current Assignee: Newham, Paul
• Original Assignee: Newham, Paul
• Inventors: Newham, Paul
• Granted Patent: US 6,778,090 B2
• Time in Patent Office: Days
• US Class Current: 340/573.1
• CPC Class Codes: A61B 2562/0214 Capacitive electrodes
• CPC Class Codes: A61B 2562/046 in a matrix array
• CPC Class Codes: A61B 2562/226 comprising means for identifying the connector, e.g. to prevent incorrect connection to socket
• CPC Class Codes: A61B 2562/227 Sensors with electrical connectors
• CPC Class Codes: A61B 5/1115 Monitoring leaving of a patient support, e.g. a bed or a wheelchair
• CPC Class Codes: A61B 5/6892 Mats
• CPC Class Codes: A61B 90/90 Identification means for patients or instruments, e.g. tags

Abstract

A capacitive array is housed within a polyester mat or other appropriate nonconductive substrate material which is interconnected with a control module. The control module supplies to the capacitive array a suitable oscillator driver current and concurrently senses capacitance value changes within the capacitive array induced through dielectric shifts within the array brought about by the proximity or absence thereof of the patient'"'"'s body mass. The monitor/control module generally comprises a power supply, a driver/sensor circuit, a calibration/comparator logic circuit, a system interconnection integrity circuit, and an alarm generation circuit. It may also optionally contain a nurse call relay circuit for interconnection to a facility'"'"'s nurse call system.

Claims

1. A modular apparatus for monitoring the presence of a person within a predefined space on a bed, said bed having a mattress, said apparatus comprising:

a mattress cover having at least one flexible capacitance sensor, said at least one flexible capacitance sensor comprising a plurality of coplanar conductive elements positioned in spaced relation to one another, said mattress cover being adapted for overfitting the mattress such that a person may overlie said plurality of coplanar conductive elements when resting on the bed;

a driver/sensor circuit electrically connected to said flexible capacitance sensor for supplying a voltage between said plurality of conductive elements, detecting a change in capacitance associated with said flexible capacitance sensor in response to a change in position of a person with respect to said flexible capacitance sensor, and generating an output signal having frequency variations representative of said change in capacitance, said driver/sensor circuit being positioned adjacent said plurality of conductive elements to minimize interference from external electromagnetic fields; and

a control/monitor module electrically connected to said driver/sensor circuit for receiving said output signal from said driver/sensor circuit, analyzing said output signal to make a determination of whether said output signal is representative of a change in presence of a person within a predefined space, and generating an alarm signal if said determination is affirmative.

2. The apparatus of claim 1 wherein said mattress cover has an underside and said plurality of coplanar conductive elements is disposed on said underside of said mattress cover.

3. The apparatus of claim 1 wherein said plurality of coplanar conductive elements comprises bands of conductive ink deposited on said mattress cover.

4. The apparatus of claim 1 wherein said plurality of coplanar conductive elements comprises a pair of bands spanning the width of said mattress cover.

5. The apparatus of claim 1 wherein said mattress cover has an underside and wherein said plurality of coplanar conductive elements comprises a pair of bands of conductive ink deposited on said underside of said mattress cover, said pair of bands spanning the width of said mattress cover.

6. The apparatus of claim 1 wherein said plurality of coplanar conductive elements comprises bands of conductive threads woven into said mattress cover.