communication framework for Pedestrian Detection System
As the number of vehicles on roads is increasing, so is the danger of accidents. Between the years 1992 and 2002 approximately 70% of all accidents in Ireland happened on rural roads, which are defined by the National Roads Authority as roads with the speed limit exceeding 40 mph (64.4 km/h),. In this dissertation we describe the design of a communication framework for a Pedestrian Detection System (PDS) that has the goal of decreasing the risk of accidents involving pedestrians on rural roads. The PDS aims to find the optimal way of detecting pedestrians, especially in dangerous places and in bad weather conditions, thus increasing the safety on the road. The system is a part of the bigger Smart Roads project carried out by Trinity College Computer Science Department. The solution we describe is based on the beacon approach and makes an assumption that pedestrians carry beacons that may for example be embedded in high visibility vests. The beacons send radio signals periodically which are received by Mica2 motes placed along the road. The strength of the radio signal (RSSI) received by the motes placed on the road is then sent to a base station for further processing. The base station infers the location of the beacon in relation to the motes placed along the road using acquired information and multicasts the location information over an Ethernet connection using User Datagram Protocol (UDP). The framework makes the assumption that the data will be send over the wireless link, received by a car’s on board system and communicated to the driver. The proposed technology considers the use of the 802.11b protocol used in combination with directional antennas which should allow for establishing the connection over a range of 400-500 metres. In this paper we present the software developed for both the Mica2 motes written in NesC as well as the software for the base station written in Java. We also describe the routing protocol designed for the motes that allows them to communicate the data to the base station over the network of interconnected motes. We present the results of tests that evaluate the suitability of the hardware used in the project. The tests of the software measure it’s performance and investigate whether it may be treated as a starting point for further development.