Passive Audio Sensor for Battery-Powered Smoke Detector

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Solution Overview

Problem

Existing battery-powered devices without native communications capabilities face challenges in cost-effective integration of sensing and reporting functionality, particularly in devices like smoke detectors, where power consumption is a concern due to the low alarm activation state duration.

Innovation Solution

A communication device with a processing circuit in sleep and awake modes, equipped with a wireless communications circuit and a passive sensor powered by audio signals, allowing it to switch modes without significant energy consumption, enabling wireless message sending during alarm triggers, and housed in a compact battery compartment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If a passive sensor powered by audio signals is used for detection, then power consumption is reduced, but measurement precision may be compromised due to approximation of audio signals

Engineering Contradiction:

Improvepower consumptionVSAvoiddetection accuracy

Core Design Contradiction:

Use of energy by moving objectVSMeasurement precision

Solution Approach 1:

The passive sensor is powered by the audio signals themselves rather than requiring an external power source. The audio signals impinging on the passive sensor provide the energy needed for detection, allowing the system to operate without additional power consumption while maintaining detection capability.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The system accepts approximation of audio signals rather than requiring precise measurements. By changing the parameter requirement from exact precision to acceptable approximation, the system achieves power efficiency while still functioning effectively for alarm detection purposes.

Inventive Principle:

Principle #35Parameter changes

2Adaptability or versatility

If wireless communications capability is added to battery-powered devices, then reporting functionality is improved, but power consumption increases

Engineering Contradiction:

Improvecommunications capabilityVSAvoidpower consumption

Core Design Contradiction:

Adaptability or versatilityVSUse of energy by moving object

Solution Approach 1:

The processing circuit operates in periodic cycles, alternating between sleep mode and awake mode. The wireless communications circuit only activates when needed to send alarm status messages, rather than operating continuously. This periodic operation dramatically reduces power consumption while maintaining the ability to report alarm states.

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The system dynamically switches between different operational states (sleep and awake modes) based on detection needs. The processing circuit transitions from a low-power sleep state to an active awake state only when alarm conditions are detected, optimizing power usage based on real-time requirements.

Inventive Principle:

Principle #15Dynamics

3Reliability

If processing circuit operates continuously in awake mode, then detection reliability is improved, but power consumption increases

Engineering Contradiction:

Improvedetection reliabilityVSAvoidpower consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The processing circuit uses periodic operation with distinct sleep and awake modes. During normal operation, the circuit remains in low-power sleep mode and only activates to full processing power when alarm conditions are detected by the passive sensor, maintaining reliability while minimizing power consumption.

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The passive sensor continuously monitors for alarm conditions without requiring the processing circuit to be active. The useful detection action continues uninterrupted through the passive sensor, while the power-consuming processing circuit remains in sleep mode until activation is needed.

Inventive Principle:

Principle #20Continuity of useful action

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

This solution reduces power consumption and enables cost-effective addition of communications capabilities to devices like smoke detectors, allowing efficient detection and reporting of alarm states without frequent power drains, while maintaining compatibility with standard battery form factors.

Implementation Method 1

a passive sensor, powered by audio signals impinging on the passive sensor, that provides at least an approximation of an audio signal to the processing circuit

Methodology Applied

Scientific EffectAcoustic energy harvesting: Photoacoustic Effect

Data Source

PatentUS10475318B2Battery-powered device having a battery and loud sound detector using passive sensing

Publication Date: 2019.11.12 ROOST

AI summary

A communication device comprises a processing circuit having at least two modes, a sleep mode and an awake mode, a wireless communications circuit that can wirelessly send a message as to whether an alarm has been triggered, and a passive sensor, powered by audio signals impinging on the passive sensor, that provides at least an approximation of an audio signal to the processing circuit so as to cause the processing circuit to switch between the at least two modes. The communication device can be housed in a housing sized to fit into a battery compartment.