Power-Saving Position Sensitive Detector with Adaptive Infrared Emission
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Solution Overview
Problem
Position sensitive detectors (PSDs) in smart bathroom products face high power consumption due to increased emitting current and frequent signal averaging, leading to reduced battery life and frequent replacements.
Innovation Solution
Implementing a method that adjusts infrared light emitting strength modes based on signal strength, switching to weaker modes when signal strength is high and stronger modes when signal strength is low, and adjusting signal acquisition frequencies to conserve power.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If an emitting current larger than that of the ordinary infrared sensor is used for signal collection, then the signal strength for sensing objects with low reflectivity is increased, but the power consumption increases
Solution Approach 1:
The patent applies dynamics by making the emitting current adjustable rather than fixed. The control unit dynamically adjusts the emitting current of the infrared light emitting device based on the detected signal strength, switching between different current levels (first current level for weak signals, second current level for strong signals) to optimize both measurement precision and power consumption.
Solution Approach 2:
The patent changes the parameter of emitting current from a constant value to a variable parameter. By adjusting the current parameter based on signal strength feedback, the system can maintain adequate signal levels for low-reflectivity objects while reducing power consumption when strong signals are already detected.
2Measurement precision
If an approach of obtaining an average value of signals collected for multiple times in unit time is used to increase detection precision, then the precision for detecting distance to objects with weak reflectivity is increased, but the power consumption increases
Solution Approach 1:
The patent applies partial action by performing signal averaging selectively rather than continuously. The control unit determines whether to perform multiple signal collections and averaging based on the current emitting mode and signal strength requirements, avoiding unnecessary repeated measurements when single measurements are sufficient, thus reducing power consumption while maintaining detection precision when needed.
3Reliability
If the PSD is used to detect distance instead of signal strength, then the sensing failure for low reflectivity objects is overcome, but the power consumption is larger than ordinary infrared sensors
Solution Approach 1:
The patent implements feedback control where the control unit monitors the signal strength detected by the PSD and adjusts the emitting current accordingly. This feedback mechanism ensures reliable sensing for low-reflectivity objects by increasing current when needed while reducing current (and power consumption) when the detected signal is already sufficient, thus maintaining sensing reliability while optimizing power usage.
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 approach reduces power consumption while maintaining detection precision, extending battery life and reducing the need for frequent replacements.
Implementation Method 1
an infrared emitter emits a certain wavelength of infrared light, and after the infrared light is reflected from a human body and received by an infrared receiver
Implementation Method 2
after the infrared light is reflected from a human body and received by an infrared receiver
Implementation Method 3
The PSD achieves the automatic sensing function by determining the distance from itself to the subject instead of by determining the strength of the reflected signal
Data Source
AI summary
A method for saving power consumption of a position sensitive detector used in a smart bathroom product includes changing infrared light emitting strength modes depending on the received strength of reflected infrared light. If the emitting mode is already the strongest, and the strength of the reflected infrared light received back from a reflecting object is weak, the method includes conducting multiple subsequent emissions and averaging the returns to estimate a distance to the infrared light reflecting object.