Occupancy Sensor Dynamic Sensitivity Adjustment
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Solution Overview
Problem
Existing occupancy sensing systems, particularly outdoor PIR sensors, face challenges in accurately detecting human presence due to varying ambient temperatures and lack of time-based customization, leading to inefficient energy savings.
Innovation Solution
An occupancy sensor that adjusts its sensitivity and operational characteristics based on ambient temperature and time of day using a combination of passive infrared, temperature sensing, and photodetector elements, with a processor configuring the sensor into different operating modes to optimize energy management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If PIR occupancy sensors are used in outdoor applications with fixed sensitivity settings, then the device complexity is reduced, but the measurement precision deteriorates due to inability to differentiate heat signatures in varying ambient temperatures
Solution Approach 1:
The patent implements dynamic sensitivity adjustment by introducing a temperature sensing element that continuously monitors ambient temperature and automatically configures the PIR sensor's detection threshold accordingly. This dynamic adaptation allows the system to maintain high measurement precision across varying thermal environments without manual intervention, resolving the contradiction between fixed simplicity and adaptive precision.
Solution Approach 2:
The system incorporates feedback mechanisms where temperature sensor data is fed back to the processor, which then adjusts the PIR sensor's operating parameters in real-time. This closed-loop control ensures optimal detection accuracy is maintained despite environmental temperature changes, eliminating the need for multiple fixed-configuration sensors while preserving measurement precision.
2Adaptability or versatility
If PIR occupancy sensors operate with fixed detection profiles, then the ease of operation is improved, but the adaptability deteriorates due to lack of time-based customization for optimum energy savings
Solution Approach 1:
The patent enables the occupancy sensor system to self-configure based on time-of-day information received from external sources. The processor automatically adjusts detection profiles and load control parameters according to pre-programmed time schedules, eliminating the need for manual configuration while providing high adaptability to different operational periods and occupancy patterns.
Solution Approach 2:
The system dynamically changes operational parameters such as detection sensitivity thresholds and load control timing based on time-of-day data. This parameter adaptation allows the system to optimize energy savings during different periods (e.g., stricter thresholds during low-activity nighttime hours) without requiring user intervention, thus achieving both adaptability and ease of operation.
3Reliability
If occupancy sensors use fixed sensitivity thresholds, then the manufacturing precision requirements are reduced, but the reliability deteriorates in environments with extreme temperature variations
Solution Approach 1:
The patent combines the PIR occupancy sensor with a temperature sensing element and integrates their functions through a processor that correlates thermal data from both sensors. This merged system allows the processor to distinguish between ambient temperature changes and actual occupancy-induced thermal changes, significantly improving detection reliability in extreme temperature environments while adding only moderate complexity through the integration of an additional sensor and processing logic.
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
Enhances the accuracy of occupancy detection and energy savings by fine-tuning sensitivity and operational parameters according to environmental conditions, ensuring efficient lighting control in outdoor settings.
Implementation Method 1
PIR occupancy sensors operate by sensing a body having a heat signature in excess of background infrared (IR) levels
Implementation Method 2
a temperature sensing element...identifying an ambient temperature of the monitored area
Implementation Method 3
a photodetector...identifying an ambient light level of the monitored area
Data Source
AI summary
An occupancy sensor is disclosed including a passive infrared (PIR) sensing element, a temperature sensing element, and a processor. The processor receives temperature signals from the temperature sensing element and configures the occupancy sensor into a selected operating mode based the received temperature signal. The operating mode may be associated with a predetermined sensing threshold of the PIR sensing element. The processor controls an associated load based on the selected operating mode and the received occupancy signals. The occupancy sensor can alternatively include an occupancy sensing element and a photodetector. Based on the amount of light detected by the photodetector over time, the occupancy sensor can calculate a rough estimate of time of day, and can automatically adjust one or more sensing and/or operational characteristics based on that time of day determination. A photosensor may implement daylight harvesting based on different light levels associated with different times of day.