An implementation of hierarchical signal processing on wireless sensor in TinyOS environment

Abstract

Wireless intelligent sensor networks have become a major infrastructure for deeply embedded systems. As these systems typically operate under stringent energy constraints, a careful consideration of computation and communication is crucial for extended system lifetime. To achieve extended lifetime on a limited energy budget the existing sensor platforms feature limited communication bandwidth, processing power, and interfacing capabilities. We propose to augment a general-purpose sensor platform by low-power, intelligent signal processing modules. This approach allows on-sensor parallel signal processing. In this paper we present an implementation of a sensor node featuring 2-tier hierarchical organization. The upper level is realized using the Telos wireless platform, and the lower level is a custom Intelligent Signal Processing Module (ISPM). The ISPM is developed as an application-specific sensor board for health monitoring applications. It features two accelerometers, a bioamplifier, and a microcontroller used for preprocessing and communication with the Telos platform. Telos features ZigBee wireless interface and can communicate to an application server through a network coordinator. The application server represents a third tier in the hierarchical system. The server seamlessly integrates sensors into a wireless body area network of physiological sensors. We describe the system architecture and software support implemented in TinyOS environment.

Wireless sensor networks for personal health monitoring: Issues and an implementation

“…Our WWBAN prototype consists of multiple ActiS sensor nodes that are based on a commonly used sensor platform and custom sensor boards [14,19]. The initial WWBAN setting includes a sensor node that monitors both ECG activity and the upper body trunk position and two motion sensors attached to the user's ankles to monitor activity.…”

A wireless body area network of intelligent motion sensors for computer assisted physical rehabilitation

“…In this paper, we present a general system architecture and describe a recently developed activity sensor "ActiS". ActiS is based on a standard wireless sensor platform and a custom sensor board with a one-channel bio amplifier and two accelerometers [11]. As a heart sensor, ActiS can be used to monitor heart activity and position of the upper trunk.…”

A WBAN System for Ambulatory Monitoring of Physical Activity and Health Status: Applications and Challenges

“…Each ActiS platform utilizes a standard Telos platform from Moteiv [9] and a custom intelligent signal processing daughter card, which is attached to the Telos platform [10]. The Telos platform is an ideal fit for this application due to its small footprint (size of two AA batteries) and open source system software support.…”

“…The Telos platform features a 10-pin expansion connector with one UART (Universal Asynchronous Receiver Transmitter) and I general-purpose I/O lines, and three analog input lines. Two custom boards, an IAS (Intelligent Activity Sensor) and an ISPM (Intelligent Signal Processing Module), have been developed as daughter boards for the Telos platform [10]. The ISPM board integrates a onechannel bio-amplifier and three accelerometer channels with a low power microcontroller, while the IAS board is a stripped down version of the ISPM with only accelerometer sensors and signal conditioning for a force sensing resistor that can be used as a foot switch.…”