D. Antolín

Reliable Lifespan Evaluation of a Remote Environment Monitoring System Based on Wireless Sensor Networks and Global System for Mobile Communications

The use of wireless sensor networks (WSN) for monitoring physical and chemical variables in large areas allows density and frequency measurements which have been unavailable to date in classical measurement systems. To fully take advantage of this technology in a particular application, besides an accurate design and selection of all the components involved in its operation, it is essential to dispose of reliable lifetime estimation prior to deployment. This paper presents an experimental approach to determine the actual lifetime of such battery-operated systems, making use of a custom WSN architecture, and for different batteries technologies. To render a reliable evaluation, the energy consumption of the sensor nodes under their different operation modes, in correlation with the battery characteristics and the voltage regulation system, is jointly considered. The result is a complete and practical lifetime model, whose appropriate performance has been validated in a real deployment scenario.

Data management of Wireless Sensor Network implemented in rural environments with SMS communication protocol

The use of wireless sensor networks for monitoring physical and chemical parameters in large regions far from populations allows for real-time monitoring with high levels of spatial resolution. However, to transmit those data to a control center for its analysis and interpretation, it is often necessary to use communication technologies with large distance ranges such as GSM/GPRS networks. This paper presents a study of the implementation of a communications system to transmit via SMS the data collected from a Wireless Sensor Network to a control system located out of the range of the node transceivers, analyzing the correlated constraints imposed in the network size and its energy requirements.

A Wearable Wireless Sensor Network for Indoor Smart Environment Monitoring in Safety Applications

This paper presents the implementation of a wearable wireless sensor network aimed at monitoring harmful gases in industrial environments. The proposed solution is based on a customized wearable sensor node using a low-power low-rate wireless personal area network (LR-WPAN) communications protocol, which as a first approach measures CO2 concentration, and employs different low power strategies for appropriate energy handling which is essential to achieving long battery life. These wearables nodes are connected to a deployed static network and a web-based application allows data storage, remote control and monitoring of the complete network. Therefore, a complete and versatile remote web application with a locally implemented decision-making system is accomplished, which allows early detection of hazardous situations for exposed workers.

WubiNet: A flexible WSN for applications in environmental monitoring

The use of wireless sensor networks for monitoring physical and chemical parameters in large regions far from populations allows for real-time monitoring with high levels of spatial resolution. This paper presents WubiNet, a wireless network designed for monitoring large regions. Depending on the available infrastructures, the network can be operating for two years using only batteries, or its coordinator can be powered by solar cells to guarantee the transmission of the collected data by SMS using GSM/GPRS technology or satellite phones. The data are transmitted to a base station located out of the range of the node transceivers, where can be represented and analyzed.

A versatile single/differential quasi-digital converter for portable sensing applications

This paper presents a new high performance 1.2 V - 0.18 μm CMOS voltage-to-frequency converter (VFC) that can be used either in single or differential mode to digitize sensor read-out signals in wireless sensor network applications. The proposed VFC works properly over the entire input range with output frequencies ranging between 0.0 and 0.9 MHz, which allows the sensor node microcontroller optimally perform the final digitalization. It achieves high linearity (0.009% linearity error) with low power consumption (72 μW) for a temperature range of -40 to 120°C) and supply voltage variations of 30%.

An electronic interface for measuring CO2 emissions in embedded systems

The ever-increasing application of wireless sensor networks in many different fields is causing a growing demand of low-cost energy-efficient sensors for monitoring physical variables such as temperature, pressure or gas concentration. This paper presents a conditioning system for low-cost non-dispersive infrared gas sensors used to measure the CO2 concentration in an open air environment. It mainly consists of an amplification and filtering circuit that adapts the small and noisy signal provided by the sensor to a signal which can be easily read by a low-power microcontroller. The proposed interface presents a good trade-off between energy consumption and accuracy, compatible with the energy requirements of wireless sensor network applications. Test performed connecting the system interface to a node sensor in a wireless sensor network using a simple communications protocol only causes a low reduction in the operating life of the node.

A Compact Energy Harvesting System for Outdoor Wireless Sensor Nodes Based on a Low-Cost In Situ Photovoltaic Panel Characterization-Modelling Unit

This paper presents a low-cost high-efficiency solar energy harvesting system to power outdoor wireless sensor nodes. It is based on a Voltage Open Circuit (VOC) algorithm that estimates the open-circuit voltage by means of a multilayer perceptron neural network model trained using local experimental characterization data, which are acquired through a novel low cost characterization system incorporated into the deployed node. Both units—characterization and modelling—are controlled by the same low-cost microcontroller, providing a complete solution which can be understood as a virtual pilot cell, with identical characteristics to those of the specific small solar cell installed on the sensor node, that besides allows an easy adaptation to changes in the actual environmental conditions, panel aging, etc. Experimental comparison to a classical pilot panel based VOC algorithm show better efficiency under the same tested conditions.

Analysis and implementation of a wireless sensor network with remote access through SMS

The use of wireless sensor networks for monitoring physical and chemical parameters in large regions far from populations allows for real-time monitoring with high levels of spatial resolution. This paper presents WubiNet, a wireless network designed for monitoring large regions. Depending on the available infrastructures, the network can be operating for two years using only batteries, or its coordinator can be powered by solar cells to guarantee the transmission of the collected data by SMS using GSM/GPRS technology or satellite phones. The data are transmitted to a base station located out of the range of the node transceivers, where can be represented and analyzed.