Inductive Object Detection Using Digital Input Pins
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Solution Overview
Problem
Conventional sensors for detecting inductive objects using analog components are costly and complex, making them unsuitable for adaptation in various applications.
Innovation Solution
A system utilizing an inductive sensor circuit generating an oscillating analog waveform coupled to a digital input pin of an integrated circuit (IC) device, which compares the waveform with threshold voltage levels to produce a digital pulse, allowing for detection of changes in the electromagnetic field environment without analog components, and optionally using a timer input capture pin for additional functionality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional analog components (analog comparator, DAC) are used to detect inductive objects, then detection accuracy is maintained, but circuit cost and complexity increase
Solution Approach 1:
The patent replaces the mechanical/analog system (analog comparator, DAC circuit) with a digital system. The digital input pin and digital interface circuitry sample the oscillating waveform and generate digital pulses, eliminating the need for analog components while maintaining detection functionality through digital signal processing
Solution Approach 2:
The patent extracts and removes the analog components (analog comparator, DAC) from the detection circuit, keeping only the essential sensing function. The inductive sensor circuit is retained but its output is processed digitally rather than analog, simplifying the overall circuit architecture
2Reliability
If conventional analog components are used for EMF detection, then detection functionality is achieved, but manufacturing cost increases
Solution Approach 1:
The patent employs inexpensive digital input pins and standard digital interface circuitry that are readily available in most integrated circuits, replacing costly analog components. These digital components are mass-producible and integrate easily into standard manufacturing processes, significantly reducing per-unit cost
Solution Approach 2:
The patent uses a digital input pin that can serve multiple functions - it can detect the oscillating waveform from the inductive sensor, generate digital pulses, and interface with standard digital processing logic. This universal digital interface replaces specialized analog components, reducing overall system cost and improving manufacturability
3Ease of operation
If analog comparator with DAC is used to generate sensor signal, then sensor output is obtained, but adaptability to different applications decreases
Solution Approach 1:
The patent enables easy adaptation to different applications by changing digital parameters such as threshold voltage levels, sampling frequency, and pulse generation timing. These parameter adjustments can be made through software or simple digital component selection, allowing the same basic circuit to serve multiple applications without hardware redesign
Solution Approach 2:
The patent introduces dynamic adjustability through digital means - the threshold levels and sampling parameters can be dynamically changed based on application requirements. This contrasts with fixed analog component values and enables the circuit to adapt to different sensing ranges, frequencies, and application-specific requirements
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 results in a simple, inexpensive circuit design that can be easily adapted to different applications, enabling effective detection of inductive objects while allowing the processor to enter sleep mode during timer operations.
Implementation Method 1
A conventional sensor for measuring changes in an EMF environment is an inductor-capacitor ('LC') oscillator circuit. The LC circuit can be charged by running current through it, and then letting the LC circuit oscillate freely. The resulting oscillation of energy creates an oscillating waveform
Implementation Method 2
When a metallic object is close to the coil, the LC oscillator dissipates its energy faster because of the inductive coupling the coil forms with the metallic object. The magnetic coupling results in more rapid decay of the waveform envelope
Data Source
AI summary
A system for detecting inductive objects includes an inductive sensor circuit for detecting changes in an electromagnetic field (“EMF”) environment and an integrated circuit (“IC”) device. The inductive sensor circuit generates an oscillating analog waveform with an envelope that indicates changes in the EMF environment. The oscillating waveform is coupled to the digital input pin of the IC. A digital interface circuit in the IC is coupled to the digital input pin and is configured for detecting if the oscillating waveform exceeds high and low threshold voltage levels. The detecting results in a digital pulse which represents changes in the EMF environment. In another implementation, a timer input capture pin can be used to detect the waveform envelope decay by storing the time when the waveform crosses a threshold value during a time period. A reduced capture time after the time period expires indicates a change in the EMF environment.