SPAD Proximity Sensing for Adaptive Microwave Spill Control
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Solution Overview
Problem
Microwave ovens often experience spills and undercooking due to user-set cooking times that do not account for varying food types, sizes, and oven power ratings, leading to inefficiencies and messes.
Innovation Solution
Integration of a proximity detector using an array of Single Photon Avalanche Diodes (SPADs) to monitor surface movements of contents within the oven, connected to control circuitry and logic modules for adaptive cooking programs and spill prevention.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If user-set cooking times are used in microwave ovens, then the oven can operate with simple controls, but spills and undercooking occur due to varying food types and sizes
Solution Approach 1:
The system uses a proximity detector to continuously monitor the surface of food contents during heating. When the detector senses that contents are rising or spilling, it automatically adjusts or terminates the cooking cycle, providing real-time feedback control that prevents spills and ensures consistent cooking results without requiring complex user input
Solution Approach 2:
The microwave oven autonomously monitors its own cooking process using the proximity detector and automatically responds to detected conditions. The system serves itself by detecting when food is ready or when spilling is imminent and taking corrective action without user intervention, transforming from a passive timer-based device to an active self-regulating system
2Adaptability or versatility
If recommended cooking times from manufacturers are provided, then cooking guidelines are available, but spills still occur because these are only guidelines and not adaptive to actual cooking conditions
Solution Approach 1:
The proximity detector provides real-time feedback on actual cooking conditions by monitoring content surface position. This feedback loop allows the system to adapt the cooking process dynamically, transitioning from static recommended times to adaptive control that responds to actual food behavior, thereby reliably preventing spills
3Measurement precision
If an array of SPADs is used for proximity detection, then precise surface movement detection is achieved, but device complexity increases
Solution Approach 1:
The system replaces complex mechanical or capacitive sensing approaches with an optical detection system using SPADs. The SPAD-based proximity detector uses photodetection principles to achieve high-precision surface movement monitoring with improved signal-to-noise ratio and detection speed, substituting optical measurement for more complex alternative sensing mechanisms
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
Enables precise control of cooking times and profiles, preventing spills and ensuring consistent heating by continuously monitoring and responding to surface movements of contents, thereby improving cooking outcomes.
Implementation Method 1
The initiating charge carrier can be photo-electrically generated by a single incident photon striking the high field region. It is this feature which gives rise to the name 'Single Photon Avalanche Diode.'
Implementation Method 2
A SPAD is based on a p-n junction device biased beyond its breakdown region. The high reverse bias voltage generates a large enough electric field such that a single charge carrier introduced into the depletion layer of the device can cause a self-sustaining avalanche via impact ionization.
Implementation Method 3
The illumination source may be reflected by the content to the array of SPADs.
Data Source
AI summary
An oven may include a housing having a cooking receptacle configured to hold content therein, a heating element carried by the housing and configured to heat the content, and a proximity detector carried by the housing in the cooking receptacle and configured to detect surface movement of the content. The proximity detector may include at least one SPAD.