In my thesis, I examine the applicability of the network coupler – network independent transducer structure introduced by the IEEE 1451 standard, to ZigBee networks. My task was to design a data acquisition system, where the part responsible for network coupling and the part responsible for the measurements is separated by a well-defined – hardware or software based – interface.
The thesis starts with the examination of the requirements towards outdoor sensor networks, extended with the task-specific expectations, such as the employment of Atmel ZigBit modules, the use of the BitCloud software stack running on them, and the application of a structure applying the philosophy of the IEEE 1451 standard.
The ZigBee standard is shortly introduced along with its implementation for Atmel ZigBit modules, the BitCloud. The IEEE 1451 family of standards is summarized, and some of its important elements, like the networked transducer structure, the physical unit and data representation method are emphasized.
In the next chapter I describe some of the questions and problems that I came along during the application of the IEEE 1451, and describe the rough specification of the system.
I describe a digital, point-point interface, which I specified to the structure that separates the functions in hardware, on the grounds of the IEEE 1451.2 TII interface, optimizing for energy efficiency. A wireless hand tremor measurement system is described that partially utilizes the interface introduced previously.
I sketch the system plan for the sensor network utilizing the software interface structure, and describe the problems that I came along during its realization. I present the application running on the network couplers, and I sketch a general software buildup for facilitating the integration of new transducer blocks to the system. I present the BSP block responsible for handling the calendar IC keeping the time for the nodes, and the development circuitry designed for aiding the development process.
At the end of the thesis I summarize, rate and compare the interface solutions presented in the document.