Real time system uses double radio feature in Waspmote sensor board
Spanish startup Libelium has developed a Vehicle Traffic Monitoring Platform as part of its Smart Cities solution that combined Bluetooth sensors in a Zigbee network.
The platform is capable of sensing the flow of Bluetooth devices in a given street, roadway or passageway while differentiating hands-free car kits from pedestrian phones. Sensor data is then transferred by a multi-hop ZigBee radio, via an internet gateway, to a server. The traffic measurements can then be analysed to address congestion of either vehicle or pedestrian traffic.
The Platform uses the new Expansion Radio Board for Waspmote which allows two different types of radio to be connected at the same time. In this case a Bluetooth radio is used as a sensor to make inquiries and to detect nearby devices, while the ZigBee radio sends the information collected using its multi-hop capabilities. Six power levels allow sensor operators to set an “inquiry zone” from between 10 and 50 metres and Adaptive Frequency Hopping (AFH) allows the Bluetooth radio to identify channels already in use by ZigBee and WiFi devices and thus avoid interference.
“With widespread use of Bluetooth devices both vehicular and pedestrian traffic can be monitored anonymously by detecting and tracking the MAC addresses of such devices,” said Libelium’s CTO David Gascón. “The platform can help drivers avoid congested roads through provision of real time warnings on electronic displays or via smartphone applications”. Similarly, pedestrian monitoring enables improvements to be made in the operation of airports, shopping centres, tourist attractions and sports stadiums. Such data can even be used to assess the suitability of emergency evacuation plans or even to detect ‘hot’ routes inside commercial centres for marketing and product placing purposes.