Doorbell Shunt Circuit and PIR Motion Detection

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Solution Overview

Problem

Current audio/video (A/V) recording and communication doorbell systems face challenges in connecting to existing household AC power supplies without causing inadvertent sounding of the signaling device, and they struggle with motion detection under low light conditions due to limitations in infrared LEDs and confusion from reflected infrared light.

Innovation Solution

The A/V recording and communication doorbell system limits its power consumption to avoid triggering the signaling device and incorporates passive infrared (PIR) sensors and a light sensor to enhance motion detection capabilities, especially under low light conditions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Duration of action of stationary object

If the A/V recording and communication doorbell draws power from the household AC power supply, then it can operate continuously, but it causes the signaling device to sound inadvertently

Engineering Contradiction:

Improvecontinuous operationVSAvoidinadvertent signaling

Core Design Contradiction:

Duration of action of stationary objectVSObject-generated harmful factors

Solution Approach 1:

The patent introduces a shunt circuit as an intermediary component between the AC power supply and the signaling device. The shunt provides an alternative current path that prevents the doorbell's power consumption from triggering the signaling device's activation threshold, thereby allowing continuous operation without inadvertent signaling.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent modifies the electrical parameters of the power circuit by introducing a shunt that changes the current distribution. This parameter change allows the doorbell to draw sufficient power for continuous operation while keeping the current through the signaling device below its activation threshold.

Inventive Principle:

Principle #35Parameter changes

2Difficulty of detecting and measuring

If infrared LEDs are used for motion detection, then the doorbell can detect motion, but reflected infrared light causes confusion and reduces detection accuracy

Engineering Contradiction:

Improvemotion detection capabilityVSAvoiddetection accuracy

Core Design Contradiction:

Difficulty of detecting and measuringVSMeasurement precision

Solution Approach 1:

The patent introduces passive infrared (PIR) sensors as an intermediary detection mechanism that detects thermal infrared radiation from moving objects rather than relying on active infrared LEDs. This intermediary approach eliminates the confusion caused by reflected infrared light while maintaining motion detection capability.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces the active infrared LED-based motion detection system with a passive infrared (PIR) sensor system. This substitution changes the detection mechanism from emitting and detecting reflected light to detecting thermal radiation directly, thereby eliminating the problem of reflected light confusion.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Illumination intensity

If the doorbell uses active infrared LEDs for illumination and motion detection, then it can operate in low light conditions, but the system complexity increases

Engineering Contradiction:

Improvelow light operationVSAvoidsystem complexity

Core Design Contradiction:

Illumination intensityVSDevice complexity

Solution Approach 1:

The patent replaces the complex active infrared LED system with a simpler passive infrared (PIR) sensor system. This substitution eliminates the need for infrared LEDs, associated control circuits, and synchronization mechanisms, thereby reducing system complexity while maintaining low light operation capability through thermal detection.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 allows the doorbell to be connected to the existing AC power supply without unintended signaling and improves motion detection range and accuracy, especially at night or in low light, by using PIR sensors and a light sensor to differentiate actual light intensity.

Implementation Method 1

incorporates passive infrared (PIR) sensors and a light sensor to enhance motion detection capabilities

Methodology Applied

Scientific EffectInfrared radiation detection: Infrared Radiation

Implementation Method 2

incorporates passive infrared (PIR) sensors and a light sensor to enhance motion detection capabilities

Methodology Applied

Scientific EffectPhotoelectric effect: Photoelectric Effect

Data Source

PatentUS10785457B2Audio/video recording and communication devices

Publication Date: 2020.09.22 RING LLC

AI summary

An audio/video (A/V) recording and communication doorbell comprises a camera, a front button, and a motion sensor. The camera and the motion sensor are configured to work in tandem to detect motion in a field of view of the A/V recording and communication doorbell, such that a first one of the camera and the motion sensor detects motion and the other one of the camera and the motion sensor independently verifies the motion detection before an alert is sent to a user's client device. In this manner, user alerts from false alarm motion detections are reduced.