Design and Development of IoT Gateway Software System

In this research and implementation, commercially available embedded development boards are used to implement the software functions of the IoT gateway, and the goal is to enable users to view the information of industrial-grade sensors through web pages. The development board uses LinkIt™ Smart 7688 Duo, developed by MediaTek. The retail price of this board is US$30 about, more cheaper than that of Raspberry Pi (about US$60~150). The proposal scheme is economical, and provides a customizing solution for System Integrators, who want to introduce IOT service to their customers. The main functions developed additionally into the IoT gateway are those for the mechanisms of Modbus and MQTT. The Web operation interfaces are also developed corresponding to the two functions. The function of Modbus over TCP is to provide the IOT manager station for reading/writing sensor systems through the IOT gateway, and that of MQTT lets the IOT gateway automatically read sensor systems and then send data to the IOT manager station. The physical bus between the IOT gateway and sensors is RS485, which is connected to 7688 Duo with an USB-to-485 adaptor. This development skill on the IOT gateway can provide a fully customizing solution for those who develop the IOT management system, and thus they can give an economical and full IOT service for their customers.