Development of a modular master-slave instrument cluster

This paper presents the design and development of a modular master-slave instrument cluster for vehicles. The master microprocessor is designed to communicate with the slave microprocessor through a SPI interface. It serves to fetch frequency, analogue, and switch signals from sensor probes, and convert them into mileage, voltage, date/time, and alarm signals displayed on a LCD or LED module. Moreover, the positioning data of the indicating needles are transmitted via the SPI interface to the slave microprocessor upon request. In this study, a firmware is developed so that the 16 digital I/O ports of the slave microprocessor are configured with 8 digital I/O ports for generating the simulated PWM signals and the other 8 digital I/O ones for driving the micro stepper motor. With this approach, the indicating needles driven by the micro stepper motor can be operated smoothly and quietly, and also properly positioned within a desirable accuracy of 1/12°. The tested results of the entire system show that the proposed modular instrument cluster with master-slave controlling method is feasible and possesses advantages of low energy consumption, low price, flexibility, friendly interface, customized installation and easy assembly. Its extensive application for all commercial vehicle, industrial machinery, and agricultural machinery is highly expected in the future.