Method and system for human presence correlation using carbon dioxide

Patent metadata

Field	Value
Publication number	US-9470670-B2
Application number	US-201313804065-A
Country	US
Kind code	B2
Filing date	Mar 14, 2013
Priority date	Mar 14, 2013
Publication date	Oct 18, 2016
Grant date	Oct 18, 2016

Abstract

Method and system for detecting and/or quantifying recent human presence in an environment using a calculated rate of decay of carbon dioxide concentration levels within that environment. A sensor measures the change in carbon dioxide levels over time to calculate the rate of decay to equilibrium and extrapolate recent human presence. Also provided is a method and system for quantifying recent human activity in an environment using the calculated rate of decay to equilibrium.

First claim

What is claimed is:

1. A method for detecting recent human presence in a space, the method comprising the steps of:
measuring, using a carbon dioxide sensor, the concentration of carbon dioxide within said space to obtain a first carbon dioxide measurement;
measuring, using the carbon dioxide sensor, the concentration of carbon dioxide within said space after a first period of time elapses to obtain at least a second carbon dioxide measurement;
calculating the carbon dioxide rate of decay using at least said first and said second carbon dioxide measurements;
determining a carbon dioxide concentration of interest;
extrapolating the time at which the concentration of carbon dioxide in said space was approximately equivalent to said carbon dioxide concentration of interest; and
correlating said carbon dioxide rate of decay to a level of human presence in said space at said extrapolated time;
wherein the carbon dioxide sensor is an infrared gas sensor.

2. The method of claim 1 , wherein said space is a room.

3. The method of claim 1 , wherein said carbon dioxide concentration of interest is determined by a user.

4. A system for detecting recent human presence in a space, the system comprising:
measuring means configured to measure the concentration of carbon dioxide within said space to obtain a first carbon dioxide measurement and configured to measure the concentration of carbon dioxide within said space after a first period of time elapses to obtain at least a second carbon dioxide measurement;
calculating means configured to calculate the carbon dioxide rate of decay using at least said first and said second carbon dioxide measurements;
accepting means configured to accept a carbon dioxide concentration of interest;
extrapolating means configured to extrapolate the time at which the concentration of carbon dioxide in said space was approximately equivalent to said carbon dioxide concentration of interest; and
correlating means configured to correlate said carbon dioxide rate of decay to a level of human presence in said space at said extrapolated time
wherein the measuring means comprise an infrared gas carbon dioxide sensor.

5. The system of claim 4 , wherein said carbon dioxide concentration of interest is determined by a user.

6. The system of claim 4 , further comprising a user interface.

7. A non-transitory computer usable storage medium storing a computer program, the computer program configured to implement a method for detecting recent human presence in a space, the method comprising the steps of:
measuring, using the carbon dioxide sensor, the concentration of carbon dioxide within said space to obtain a first carbon dioxide measurement;
measuring, using the carbon dioxide sensor, the concentration of carbon dioxide within said space after a first period of time elapses to obtain at least a second carbon dioxide measurement;
calculating the carbon dioxide rate of decay using at least said first and said second carbon dioxide measurements;
determining a carbon dioxide concentration of interest;
extrapolating the time at which the concentration of carbon dioxide in said space was approximately equivalent to said carbon dioxide concentration of interest; and
correlating said carbon dioxide rate of decay to a level of human presence in said space at said extrapolated time;
wherein the carbon dioxide sensor is an infrared gas sensor.

8. The computer program of claim 7 , wherein said space is a room.

9. The computer program of claim 7 , wherein said carbon dioxide concentration of interest is determined by a user.

Assignees

• Src Inc

Inventors

• Angeli Mark
• Durst John
• Liddil Garrett
• Distasio Marcello M

Classifications

• G08B21/14

  Toxic gas alarms (G08B21/16 takes precedence) · CPC title

• G01N33/0067 Primary

  by measuring the rate of variation of the concentration · CPC title