Sound-Based Occupancy Tracking for Personalized HVAC Control

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing HVAC systems cannot determine the number of people present in a space or identify individuals, limiting their ability to provide personalized temperature settings and efficient energy management.

Innovation Solution

An occupancy tracking system that uses sound recognition, user device detection, and wireless signal distortion analysis to predict the number of people in a space, allowing for personalized HVAC control based on individual preferences and occupancy levels.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If proximity sensors or motion detection sensors are used to determine occupancy, then the system can detect whether a space is occupied, but it cannot determine the number of people present or identify individuals

Engineering Contradiction:
Improveoccupancy detection accuracyVSAvoidnumber of people and identity information
Core Design Contradiction:
Measurement precisionVSLoss of information

Solution Approach 1:

The patent replaces mechanical sensors (proximity sensors, motion detection sensors) with acoustic field-based detection (microphones capturing voice signals). This substitution enables the system to extract richer information from the acoustic environment, including voice presence, voice count, and voice characteristics, thereby determining both the number of people and their identities without using mechanical sensing methods.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the detection parameter from binary occupancy status (occupied/not occupied) to multiple acoustic parameters including voice presence, voice count, and voice characteristics. By analyzing these transformed parameters from the acoustic field, the system can determine the number of people and their identities, resolving the information loss problem while maintaining detection accuracy.

Inventive Principle:
Principle #35Parameter changes

2Ease of operation

If existing HVAC systems use binary occupancy detection, then the system operation is simple, but it cannot provide personalized HVAC settings for different individuals

Engineering Contradiction:
ImproveHVAC control simplicityVSAvoidpersonalized settings capability
Core Design Contradiction:
Ease of operationVSAdaptability or versatility

Solution Approach 1:

The patent introduces dynamic adaptability into the HVAC system by enabling it to identify different individuals through voice characteristics and adjust settings in real-time based on who is present. The system dynamically changes HVAC parameters (temperature, ventilation) according to the detected occupants' preferences, transforming a static binary control system into a dynamic personalized control system.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent implements feedback mechanisms where the system continuously monitors voice signals, identifies occupants, determines their preferred HVAC settings, and adjusts the environment accordingly. This closed-loop feedback enables personalized control while maintaining operational simplicity, as the system automatically adapts without requiring manual user input.

Inventive Principle:
Principle #23Feedback

3Measurement precision

If the system captures audio signals to determine occupancy, then it can identify the number of people, but it may incorrectly include voices from electronic devices

Engineering Contradiction:
Improveoccupancy count accuracyVSAvoidfalse positives from electronic devices
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent applies inversion by analyzing what voices are NOT present rather than just detecting voice presence. By examining the absence or presence of expected voice signals from known occupants, the system can distinguish between human voices and electronic device sounds, effectively filtering out false positives from TVs, radios, and other electronic devices.

Inventive Principle:
Principle #13The other way round (Inversion)

Solution Approach 2:

The patent introduces voiceprint analysis as an intermediary layer between raw audio capture and occupancy determination. This intermediary process analyzes voice characteristics and patterns to differentiate between human voices and electronic device sounds, acting as a filter that eliminates false positives while preserving accurate occupancy counting.

Inventive Principle:
Principle #24Intermediary (Mediator)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

Enables more accurate prediction of occupancy levels and personalized HVAC management, improving energy efficiency and comfort by adjusting settings according to the number and preferences of individuals in the space.

Implementation Method 1

an occupancy tracking system that uses sound recognition, user device detection, and wireless signal distortion analysis to predict the number of people in a space

Methodology Applied
Scientific EffectSound recognition: Sound

Implementation Method 2

wireless signal distortion analysis to predict the number of people in a space

Methodology Applied
Scientific EffectWireless signal distortion: Electromagnetic Induction

Data Source

PatentUS11448413B2Occupancy tracking using sound recognition
Publication Date: 2022.09.20 LENNOX IND INC
  • US11448413B2 patent drawing
  • US11448413B2 patent drawing
  • US11448413B2 patent drawing

AI summary

An occupancy tracking device configured to receive a plurality of sound samples over a predetermine time period. The device is further configured to compute an audio signature for each sound sample. The audio signature includes a numerical value that uniquely identifies characteristics of an audio signal. The device is further configured to determine a direction of arrival for each sound sample. The device is further configured to populate entries in the voice data log for the sound samples, to identify one or more clusters based on an audio signature that is associated with the populated entries, and to determine a number of clusters that are identified. The device is further configured to determine a predicted occupancy level based on the number of clusters that are identified and to control a Heating, Ventilation, and Air Conditioning (HVAC) system based on the predicted occupancy level.