3926177 is referenced by 107 patents and cites 9 patents.

A contactless activity and respiration monitor is described which includes a resilient, capacitive pad, which may be a mattress, or a pad used with a mattress, having a capacitor therein responsive to the activity or respiration of a body lying on it. Electronic capacitance sensing circuitry is disclosed which provides an indication or alarm in the event of excessive activity or apnea, or low or high respiration rate. Readouts of respiration rate, and number of events of activity may also be provided. Circuits are disclosed for filtering out large static or relatively long term changes in the capacitance of the capacitive pad while maintaining the high sensitivity necessary to sense movements caused by respiration.

Title
Activity and respiration monitor
Application Number
05/287,844
Publication Number
3926177
Application Date
September 11, 1972
Publication Date
December 16, 1975
Inventor
Holtman William H
Hardway Jr Edward V
Agent
Pohl P H
Sperber P
Assignee
Cavitron Corporation
IPC
A61b 05/00
A61B 05/113
A61B 05/11
View Original Source