Miniaturised inertial measurement units (IMU) for wireless sensor networks and novel display interfaces

This paper will present the work done in designing and fabricating miniaturised inertial measurement units (IMU's) for 2 distinct applications: a 25mm form factor wireless sensor network platform and a novel display interface. The 2 IMU's developed for the novel display interface are a Low-Dynamics sensor module that includes a 3-axis magnetometer and a 2-axis inclinometer and High-Dynamics sensing module, which consists of a complete strapdown inertial measurement system and a compass module. The IMU designed for the wireless sensor network platform is based on the High-Dynamics sensing module but realised in a 25mm x 25mm panel. This panel increases the sensory capabilities of each network node allowing the orientation of each node to be completely realized. As part of the NMRC's technology development there is a drive towards wireless nodes for sensor networks of volume in the sub 5mm region [1,2]. As a stepping stone towards this goal, the target objectives for the development of a 25mm cube module were to develop, a low volume prototyping and experimentation platform. This is for use as a platform for sensing and actuating through various parameters, for use in scalable, reconfigurable distributed autonomous sensing networks in a number of research projects currently underway in the NMRC. This paper outlines the development of the system with particular emphasis on the IMU layer. The total system is packaged in a modular 25mm cubed form factor which gives the capability for the module to be utilised in a wide variety of projects incorporating a multitude of actuators/sensors in miniaturised, mobile, autonomous systems.