Self-Powered ZigBee Wireless Sensor Nodes for Railway Condition Monitoring

Abstract

A track-borne energy transducer is a smart device for harvesting energy of trains or rail transportation systems. In this paper, the authors extend this application through introducing a self-powered ZigBee wireless sensor node. The proposed hardware prototype consists of a ZigBee coordinator at road-side and a series of sensors (Accelerometer, temperature sensor, humidity sensor, and infrared detector) connected to a ZigBee end device at rail-side. The ZigBee end device is powered by the magnetic levitation energy harvester and communicated wirelessly with the ZigBee coordinator. The magnetic levitation oscillator is selected due to its broad-band response characteristics.

Existing System

Solar energy harvesting from roadways.

Proposed System

This paper investigated the possibility of establishing a self-powered wireless sensor network by integrating the techniques of ZigBee stack protocol and energy harvesting. The target was aimed at the railway condition monitoring. Three types of track-borne electromagnetic harvester were compared and we found that energy harvesting by magnetic levitation is suitable for powering the ZigBee end device due to its wide frequency response. A hardware platform was developed and tested, indicating the feasibility of the proposed approach. Further investigation is current undertaken for evaluating the long-term performance of the self-powered ZigBee sensor nodes for the railway condition monitoring. Main challenges faced by railway engineers for railway track monitoring are: 1) power supply problem of rail-side equipment. Wired monitoring devices depend on the grid infrastructure, which needs huge investments; whereas the wireless ones require batteries which can only work for a certain time period. The railway track is very long, cross remote or natural region, rendering the replacement of batteries impossible. 2) money-consuming to deploy the railway monitoring system. It costs much to deploy traditional monitoring equipment.

Architecture

Encapsulated sensor node prototypes developed by SWJTU