An open source tracking system has been given its first public trial at the Chaos Communication Conference in Berlin.

The open source wireless tracking system for tracking people around buildings, OpenBeacon got its first public use last week at the event last week.

The system creators sold 900 tags at €10 (£8.74) each to attendees who volunteered to be tracked during the four-day event. Some attendees bought multiple tags to experiment with later.

OpenBeacon uses chips from Nordic Semiconductor that transmit and receive over the 2.4GHz frequency, which is available for unlicensed use in many countries. The chips communicated with 23 base stations positioned around the conference centre, which sent data back to a central server.

The developers of OpenBeacon worked with partners to create a three dimensional model of the conference centre and anyone could use touchscreen monitors that displayed the location of attendees on the model. Touching an attendee on the screen displayed a profile that the person could voluntarily add.

The OpenBeacon team used the congress as a showcase for the tracking technology and its implications. "At first look, you don't see anything special about the data moving around the building," said Milosch Meriac, one of the creators of OpenBeacon. However, an analysis of data collected over several days and about many people could lead to assumptions about relationships between people who may have gathered in similar spaces repeatedly, he noted.

"We wanted to make this analysis transparent so that people are more aware of what data they're willing to give away," he said. On the last day of the conference, OpenBeacon released all the data gathered over the four days so anyone could access and analyse it.

The Chaos Communication Congress is an annual conference that attracts technology enthusiasts who examine the implications of technology on society.

There are already many types of commercial systems that could be used for tracking people or things, but Meriac hoped to solve several shortcomings in those systems. He and a friend initially developed OpenBeacon after looking for a possible way to solve crowd control problems that often occur when millions of Muslim pilgrims visit Mecca each year.

They decided that radio frequency identification (RFID) would not meet requirements because the tags can only be read by passing through gates. Requiring millions of people to funnel through specific areas might only exacerbate the problem.

Other tracking systems based on WiFi exist but they often have battery-life limitations and higher costs, Meriac said.

OpenBeacon tracking devices transmit and then sleep, cutting back on power consumption. The devices could run for several months before requiring a new battery.

The devices could be distributed to 10,000 pilgrims traveling to Mecca, for example. Their identities wouldn't be important but crowd control monitors could note when many of the tagged pilgrims converge in one spot, implying that potentially many other untagged people are also in the same area, and then they could work to divert or otherwise alleviate the congestion, Meriac said.

The firmware, drivers and hardware design for the tracking devices are released under GNU/GPL open source licences. The base station designs are not currently available as open source because they were designed closely with a vendor.

Meriac hopes that other contributors will develop mesh protocols for the system so that the devices can communicate with each other rather than only with a central base station.