A. Astaras

Design and implementation considerations for an advanced wireless interface in miniaturized integrated sensor microsystems

Developments in system-on-chip and wireless technologies have led to complex electronic systems to be miniaturized to size of ingestible capsule and implantable microsystems. Inevitably such miniaturized complex systems impose some constraints on the case of an ingestible diagnostic capsule. It is desirable that system be wireless, programmable, and reusable. In this paper, we describe a wireless interface link developed for such an ingestible microsystem. It is programmable and directly controlled by the on-chip microcontroller. It is also suitable for developing complex communication protocols for conveying the data to a remote basestation. At the heart of the system lie a direct sequence spread spectrum encoder.

Integrated micro-instrumentation for dynamic monitoring of the gastro-intestinal tract

The introduction of microsystem technology into diagnostic devices is a rapidly growing field where low form-factor can significantly improve device access or patient comfort. In this paper we present our results on a lab-in-a-pill device that uses laboratory-on-a-chip and system-on-chip technology to deliver analytical data from a range of sensors, and the methodology employed to build the device.

An integrated sensor microsystem for industrial and biomedical applications

There is considerable interest in the development of ultra-miniature and low-power sensor microsystems for use in applications such as medical diagnostics, environmental monitoring and other industrial applications. Such ultra-miniature sensor microsystems must contain a large diversity of complex electronics, including sensor interfaces, signal conditioning, a microprocessor core, digital signal processing, and wireless transmission technology. In this paper, we will describe the first steps towards the development of a System on Chip for such a sensor microsystem and the methodology employed to build such a microsystems.

A sensor system on chip for wireless microsystems

Recent years have seen the rapid development of microsensor technology, system on chip design, wireless technology and ubiquitous computing. When assembled into a complex microsystem the technologies become powerful tools in medical diagnostics, environmental monitoring and personal connectivity. In this paper we describe the demonstration of a silicon chip that has all the attributes required of a microsystem for use in these applications. The design methodology we have employed is a variant of the system on chip approach whereby many intellectual property blocks are integrated at a high level in the design flow. Our intellectual property blocks include the analogue sensor instrumentation for temperature and pH, a data multiplexing and conversion module, a digital platform based around an 8-bit microcontroller, data encoding for spread-spectrum wireless transmission and a RF section requiring very few off-chip components. The chip has been fully evaluated and tested by connection to external sensors. Each block has well defined interfaces so that they can be easily reused in future designs targeted to different applications

Noise analysis on integrated multisensor microsystems

This paper presents an analysis of the noise propagated across the substrate and the electromagnetic contamination in a control chip for a wireless lab-in-a-pill. This chip integrates analogue, digital and radio frequency circuits monolithically to reduce the physical size, power consumption and packaging cost of the capsule. Several approaches to minimise noise effects were proposed and incorporated in a recently fabricated chip. Despite the presence of high frequency noise, the experimental results revealed that 8-bit A/D conversion of the sensory signals was possible with a 3 V power supply.

An on-chip programmable instrumentation microsystem for gastrointestinal telemetry applications

We have developed an integrated circuit microsystem instrument using a design methodology akin to that for system-on-chip microelectronics. The microsystem is optimised for low-power gastrointestinal telemetry applications and includes mixed-signal sensor circuits, programmable digital system, a feedback clock control loop and RF circuits that were integrated on a 5 mm /spl times/ 5 mm silicon chip using a 0.6 /spl mu/m, 3 V CMOS process. Unintended signal coupling between circuit components has been investigated and current injection into sensitive instrumentation nodes has been minimised. Tests show that the wireless instrument-on-chip worked as intended.