Radar-PIR Motion Detection for Low-False-Positive Battery Cameras

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Solution Overview

Problem

Existing motion detection systems, particularly in battery-operated cameras, suffer from high power consumption and frequent false positives due to inconsequential motion detection, leading to inefficient battery life and unnecessary video capture.

Innovation Solution

A two-stage radar and PIR-based motion detector system that combines frequency modulated continuous wave radar with passive infrared sensors, utilizing machine learning to corroborate motion detection and reduce false positives.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If motion detection is used to trigger video capture and streaming, then security monitoring capability is improved, but power consumption increases and battery life decreases

Engineering Contradiction:
Improvesecurity monitoring capabilityVSAvoidpower consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The motion detection system is segmented into multiple independent sensor types (radar and PIR sensors) that operate in parallel. Each sensor type detects different aspects of motion, allowing the system to cross-validate detections and reduce false positives while managing power consumption through selective triggering of video capture only when multiple sensors confirm motion.

Inventive Principle:
Principle #1Segmentation

2Measurement precision

If motion detection sensitivity is increased to detect all motion, then detection accuracy is improved, but false positives from inconsequential motion increase

Engineering Contradiction:
Improvemotion detection accuracyVSAvoidfalse positive rate
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The system merges the detection capabilities of radar sensors and PIR sensors into a unified motion detection system. By combining the output of these different sensor types, the system achieves higher reliability in distinguishing significant motion from inconsequential motion, as each sensor type compensates for the weaknesses of the other.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The system uses feedback mechanisms where the detection output from one sensor type influences the operation of the other sensor type. When radar detects motion, it triggers PIR to verify, and vice versa. This feedback loop allows the system to maintain high detection accuracy while filtering out false positives through cross-validation.

Inventive Principle:
Principle #23Feedback

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

The system effectively reduces power consumption and false positives by accurately distinguishing between significant and inconsequential motion, prolonging battery life and minimizing unnecessary video capture.

Implementation Method 1

determine Doppler shifts for detection of movement

Methodology Applied
Scientific EffectDoppler effect: Doppler Effect

Implementation Method 2

frequency modulated continuous wave radar

Methodology Applied
Scientific EffectRadar: Radar

Implementation Method 3

passive infrared sensors

Methodology Applied
Scientific EffectInfrared radiation: Infrared Radiation

Data Source

PatentUS12546877B1Motion detector
Publication Date: 2026.02.10 AMAZON TECH INC
  • US12546877B1 patent drawing
  • US12546877B1 patent drawing
  • US12546877B1 patent drawing

AI summary

Systems and techniques are described for motion detection. In various examples, a radar sensor may transmit at least a first frame and a second frame over a first period of time. Difference data representing differences between at least a first signal corresponding to the first frame and a second signal corresponding to the second frame may be determined by the radar sensor. First data may be determined by a passive infrared (PIR) sensor over the first period of time. A first machine learning model may generate, using the difference data and the first data, second data indicating whether motion is detected during the first period of time.