Hotplate Pot Detection Using Multi-Frequency Reflex Light Sensing
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Solution Overview
Problem
Existing pot detection systems using reflex light barriers are not reliable and efficient, often failing to accurately distinguish between a pot being present or absent, which can lead to unnecessary energy consumption and safety hazards.
Innovation Solution
A method and device utilizing a reflex light barrier with a light transmitter and receiver, where the light signal is modulated with multiple frequencies, and a controller evaluates the reflected signals to ensure accurate pot detection by checking the number and phase of frequencies, using a lock-in filter for improved reliability and immunity to interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a simple reflex light barrier with single frequency modulation is used, then the device complexity is low, but the reliability and accuracy of pot detection deteriorates due to interference and false readings
Solution Approach 1:
The light transmitter modulates the light signal with multiple periodic frequencies (at least three different frequencies). By evaluating whether the light receiver detects signals at multiple frequencies, the system achieves reliable pot detection. The periodic modulation allows distinction between actual pot presence and interference through frequency analysis.
Solution Approach 2:
The system changes the frequency parameter of the light signal from a single frequency to multiple frequencies (at least three). This parameter change enables the detection system to differentiate between reflected light from a pot and interference signals by analyzing the frequency characteristics of received signals.
2Object-affected harmful factors
If multiple frequencies are used for light signal modulation, then the reliability and immunity to interference improve, but the device complexity and evaluation effort increase
Solution Approach 1:
By using periodic modulation at multiple frequencies, the system creates distinct frequency signatures for valid pot detection signals. The controller evaluates whether signals are present at these specific frequencies, providing immunity against aperiodic or single-frequency interference while maintaining manageable evaluation complexity through frequency threshold checking.
Solution Approach 2:
The system uses feedback by comparing the detected frequency components against the expected modulation frequencies. The controller determines pot presence based on whether the light receiver detects signals at the transmitted frequencies, creating a feedback mechanism that filters interference while confirming valid detections through frequency matching.
3Measurement precision
If phase position evaluation is implemented, then the accuracy of pot detection improves, but the measurement complexity and processing time increase
Solution Approach 1:
The periodic modulation of light signals with known frequencies enables phase position evaluation. By comparing the phase of received signals against the transmitted signal phases, the system achieves accurate pot detection while limiting processing time through the use of fixed frequency references and threshold-based evaluation.
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 solution significantly enhances the reliability and safety of pot detection, reducing false positives and negatives, thereby ensuring accurate operation of hotplates and preventing potential hazards.
Implementation Method 1
A light transmitter emits light or a light signal to the pot or to the hotplate and to the pot that is placed on the hotplate. The pot in turn reflects the light or light signal, which is then received by the light receiver.
Implementation Method 2
The light or light signal emitted by the light transmitter is modulated with at least three frequencies.
Implementation Method 3
the phase position of the light signals can also be checked or compared between the light transmitter and the light receiver, preferably evaluated by a lock-in filter
Data Source
Figure 1
Figure 2~4
AI summary
In a method for pot detection of a pot placed on a hotplate with a reflex light barrier, a light transmitter emits light to the pot, with the pot reflecting the light and it being received by the light receiver, with the emitted light being modulated with at least three frequencies. In a control of the pot detection, it is checked at how many frequencies of the light transmitter the light receiver receives reflected light signals from the light transmitter, with a pot only being recognized as set up if at least two of three frequencies or more than half the number of frequencies emitted by the Light receiver detects light signals from the light transmitter.