Event-based encoding from digital magnetic compass and ultrasonic distance sensor for navigation in mobile systems

Event-based encoding reduces the amount of generated data while keeping relevant information in the measured magnitude. While this encoding is mostly associated with spiking neuromorphic systems, it can be used in a broad spectrum of tasks. The extension of event-based data representation to other sensors would provide advantages related to bandwidth reduction, lower computing requirements, increased processing speed and data processing. This work describes two event-based encoding procedures (magnitude-event and rate-event) for two sensors widely used in industry, especially for navigation in mobile systems: digital magnetic compass and ultrasonic distance sensor. Encoded data meet Address Event Representation (AER) format for further transmission, processing and visualization. Two encoding procedures and their associated AER conversion from sensor data are described, using an AVR microprocontroller to perform the task in real-time. Results are transmitted to a computer via USART, displayed and recorded using Matlab or jAER visualization tool. A comparison with classic transmitting and processing of sensor data is done to evaluate the convenience of the proposed encoding. Results show that data transmission bandwith can be reduced up to 95% under certain conditions, envisaging that pure or mixed regular/event-based data sensors are desirable for high speed transmission and low computer processing while keeping relevant information, which is highly desirable for mobile systems.

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