CAN Bus Light Bar Messaging System for Noise Reduction
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Solution Overview
Problem
Existing light bar systems for emergency or municipal vehicles face challenges with electromagnetic noise interference, labor-intensive installation processes, and lack of user-configurable lighting arrangements due to hard-wired connections and proprietary bolt patterns, which hinder interoperability and require vehicles to be taken out of service for configuration changes.
Innovation Solution
A CAN bus messaging platform that uses a light code message with metadata and a control portion, transmitted through a CAN bus, allowing for user-configurable lighting arrangements and reducing electromagnetic noise interference by eliminating the need for multiple wires, enabling rapid reconfiguration without tools.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If hard-wired connections with multiple wires are used to power and control lighting devices, then electromagnetic noise interference is reduced, but device complexity and installation labor increase
Solution Approach 1:
The patent replaces the mechanical wired connection system with a wireless communication system. Lighting devices communicate with the control unit via wireless signals (e.g., radio frequency communication), eliminating the need for multiple physical wires while maintaining control functionality. This substitution reduces electromagnetic noise interference from wired connections and simplifies the overall system complexity.
Solution Approach 2:
The patent implements a universal mounting system with standardized mounting interfaces that can accommodate different lighting devices from various manufacturers. The control unit can wirelessly communicate with and control multiple types of lighting devices (e.g., LED bars, spotlights, rotating beacons) using the same communication protocol, making the system multi-functional and interoperable without requiring device-specific wiring harnesses.
2Manufacturing precision
If proprietary bolt patterns and wire connectors are used for lighting devices, then manufacturing precision is improved, but adaptability and ease of repair worsen
Solution Approach 1:
The patent employs universal mounting brackets and standardized mounting holes that conform to common industry standards (e.g., standard roof rack patterns). These universal interfaces can accommodate lighting devices from different manufacturers without requiring proprietary adapters or custom drilling, thereby improving adaptability while maintaining sufficient manufacturing precision through standardized hole patterns.
Solution Approach 2:
The mounting system is segmented into separate functional components: a universal mounting bracket that attaches to the vehicle roof, and a lighting device that attaches to the bracket. This segmentation allows the mounting bracket to provide precise, standardized mounting points while the lighting device can be easily replaced or swapped with different models that use the same bracket interface, improving both precision and adaptability.
3Reliability
If hard-wired connections are used for lighting devices, then reliability is improved, but ease of operation and productivity worsen
Solution Approach 1:
The patent replaces mechanical wired connections with wireless communication links between the control unit and lighting devices. This eliminates the need to physically disconnect and reconnect wires during reconfiguration, allowing users to change lighting patterns, colors, and device assignments through software configuration or remote control, dramatically improving ease of operation while maintaining system reliability through established wireless communication protocols.
Solution Approach 2:
The patent implements a dynamic, reconfigurable lighting system where the control unit can change lighting patterns, intensities, and device assignments in real-time without physical reconfiguration. The wireless communication enables dynamic adjustment of lighting parameters (e.g., flashing patterns, color mixing, synchronization) during vehicle operation, making the system adaptable to different emergency situations without taking the vehicle out of service.
4Reliability
If multiple wires are routed through the light bar for each lighting device, then reliability is improved, but device complexity and loss of time increase
Solution Approach 1:
The patent replaces the multi-wire electrical connection system with a single-wire power connection combined with wireless communication for control signals. Each lighting device receives power through a simple power wire while all control and configuration data are transmitted wirelessly, reducing the number of wires routed through the light bar from multiple per device to just one power wire per device, plus a single wireless communication channel shared across all devices.
Data Source
AI summary
Techniques for communicating lighting commands through a controller area network (CAN) bus of a light bar system include generating a light code message. The light code message has a metadata portion and a value portion. The metadata portion defines a purpose of value portion. The value portion controls a state of a lighting device (e.g., a keypad's LED brightness or activation of a directional light module) in the light bar system. A data field is generated by encapsulating the light code message with an ISO-TP single frame header and a message subtype. A CAN controller generates a CAN message having an extended frame format and the data field. The CAN message is then transmitted through the CAN bus.