ZigBee modules survive encased in ice

XBee ZigBee modules were chosen to monitor the temperature of a ice skating rink.

PTC Remote Management and Service wanted to create a new way to monitor and control numerous devices spread over an area.

The company had a pilot project in mind - monitoring the temperature and environmental influences on Thialf ice skating rink in Heerenveen.

However, PTC first had to figure out how to go about creating a solution that could be embedded in -20C ice, transmit through the ice and run on ultra low battery power.

The solution came in the form of XBee ZigBee modules from Digi International's MaxStream brand.

The uMesh system specialises in data transfer and communications by means of a self-forming and self-healing mesh topology network.

The network is formed of individual nodes which can relay data off any other node in range until it reaches the destination.

Every node consists of monitoring sensors and a MaxStream XBee module.

The data gathered is relayed from XBee to XBee until it reaches a central point which routes it by either a wired Ethernet connection or via a cellular GPRS signal over IP.

This potentially allows anyone with an internet connection to access this data anywhere in the world by logging in to the PTC website and entering the appropriate username and password.

E-mail and SMS alerts can also be set up for critical notifications.

"We had previously used the MaxStream XBee modules in a transport and logistics operation for tracking and tracing trailers attached to lorries", explained Wessel Koning, Technical Director, PTC.

"So, when we needed a wireless module for uMesh Digi was the first place we turned".

For the the skating rink, nodes were placed at different points within the ice and also on wind speed and humidity sensors.

All the data was relayed to a central location, where it was added to data coming from the ice making machines themselves.

This information will now be used to determine optimal ice composition for future winter seasons.

One of the additional benefits of the XBee-based uMesh system is that even though it is low power, lasting up to five years on just two standard AA batteries, it can be used for more than simple monitoring.

The system can transmit both ways and can also be used for control applications thanks to an inbuilt microprocessor.

It is possible to link the ice making machines to the system so that when certain changes in temperature, wind, or humidity occur the machines can adjust accordingly.

Overall the project took approximately 18 months, including hardware and software development.

In the end, this solution should result in faster times on the rink by speed skaters thanks to superior ice conditions.

The International Skating Union is considering making these systems standard for all competitions.

uMesh can be used in virtually any location where conditions need to be monitored, including industrial applications.

Safety and security is increased thanks to the AES 128 bit data encryption and the ability to receive alerts when problems occur.

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