Contactless CAN Bus Reading via Magnetic Signal Extraction
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Solution Overview
Problem
Existing methods for obtaining information from a controller area network (CAN) bus require direct physical intervention, which is undesirable and potentially leads to undesirable outcomes.
Innovation Solution
A contactless CAN bus reader system comprising a sensor and decoder, where the sensor extracts signals wirelessly from the CAN bus using a sensing element, filters and amplifies the signal, and the decoder processes and transmits valid frames without direct coupling, employing error correction and frame reconstruction techniques.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If direct physical connection to CAN bus wires is made to obtain information, then information extraction capability is improved, but system reliability and safety deteriorate due to potential wire damage and installation complexity
Solution Approach 1:
The patent introduces a magnetic field as an intermediary medium between the CAN bus wires and the sensing element. The sensing element detects magnetic fields generated by current flow in the wires, enabling indirect signal extraction without physical contact. This resolves the contradiction by maintaining high signal extraction capability while eliminating risks of wire damage and improving system safety.
Solution Approach 2:
The patent replaces the mechanical contact-based signal extraction method with a magnetic field-based sensing method. Instead of physically connecting to the wires, the sensing element uses electromagnetic induction to detect signals through the magnetic field generated by current flow, thereby eliminating mechanical contact and improving reliability.
2Measurement precision
If direct physical connection to CAN bus wires is made, then signal extraction capability is improved, but device complexity increases due to installation requirements
Solution Approach 1:
By using the magnetic field as an intermediary, the patent eliminates the need for physical wire connections, splicing, or cutting. The sensing element can be positioned near the wires to detect magnetic fields, dramatically simplifying installation while maintaining signal extraction capability.
Solution Approach 2:
The patent replaces the mechanical connection system with a magnetic field-based sensing system, eliminating complex installation procedures such as wire splicing, connector attachment, and physical wiring modifications. This reduces device complexity and installation requirements.
3Measurement precision
If sensing element is positioned within threshold proximity to CAN bus lines, then signal extraction capability is improved, but electromagnetic interference increases
Solution Approach 1:
The magnetic field acts as an intermediary that allows the sensing element to detect signals at a safe distance from the CAN bus wires. This intermediate detection method reduces direct electromagnetic coupling and minimizes electromagnetic interference while maintaining sufficient signal detection sensitivity through magnetic field induction.
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 reliable extraction and transmission of CAN bus data without physically connecting to the wires, ensuring robust and compact data logging without splicing or cutting, and supporting various network configurations.
Implementation Method 1
a sensing element configured to receive the signal from a pair of lines associated with the communication bus, the sensing element to be positioned within a threshold proximity of the pair of lines
Data Source
AI summary
Systems and methods include a contactless controller area network (CAN) bus reader. The CAN bus reader may include a sensor and a decoder that extracts a signal from lines of the CAN bus, applies one or more operations to the signal, and determines a validity of a frame extracted from the signal. The decoder may include two separate evaluation branches that may operate, at least partially, in parallel to determine whether a given frame is a valid frame. The sensor and decoder may be stored in separate housing coupled together using a communication cable. At least a portion of the CAN bus may extend through a sensor housing associated with the sensor to permit a sensing element positioned within a threshold proximity to the portion of the CAN bus to extract a signal for further processing by the decoder.