Sensor networks
The crew of the helicopter opens up a crate of small computers and throws them out over the large area that is threatened by the forest fire. These computers are wireless sensor nodes that senses the environment to get information on how the fire spreads. They form a wireless network to communicate their information. The information about where the fire is and how it is spreading is collected by the firefighters and helps them take decisions on the best way to fight the fire.What is sensor networks?
Wireless sensor networks consists of a large number of small computers, sensor nodes, like the one below that can sense its environment, compute, store information and communicate wirelessly. In general, it is not known beforehand where a node is going to end up so the nodes set up an ad hoc network among themselves when they are deployed.
Uses
There are many potential uses of sensor networks in many different settings. Here are some examples:- Like the forest fire sensors in the introduction, there are many possibilities for sensor networks to gather environmental information in hard to reach areas. They could sense vibrations to predict earthquakes, chemical substances to discover pollution and numerous other things and much more.
- One example of a sensor network seen in popular culture is the tornado sensor in the motion picture Twister where the nodes were released into the tornado to collect research information.
- As a part of European Union research project a competition was held to foresee future applications in the area. Suggestions like cattle health monitoring, waste management, congestion free roads, locust control, traffic hazard warnings, structural monitoring of buildings and bridges, fetus monitoring and many more can be found at: http://www.embedded-wisents.org/competition/competition_ann.htm
Challenges
There are many different types of sensor nodes ranging from the tiny ones with very limited hardware and battery power to fairly powerful ones (e.g. nodes in running cars) with expensive hardware like GPS and virtually unlimited battery power.
In general though the sensor nodes have limited computing power, storage capacity, memory capacity and battery capacity. This demands special algorithms to get the most out of the nodes and at the same time don't drain batteries too fast. The strength of the nodes are in small size, big numbers and the broadcast medium of wireless communication.
Operating system
A widely used operating system for sensor network nodes is TinyOS. TinyOS is like a combination of an OS and a library that make programming sensor nodes easy. It is highly modular the possibility to replace and pick and choose different parts as needed. It is event driven to accommodate the for realtime reactions and in the other end supports having nodes have an sleep-awake cycle to save battery power.
To save space TinyOS is compiled together with the application so that only the used parts of the OS takes place at the node. This also makes TinyOS a good platform to try out changes and new ideas.
The Distributed Computing and Systems group
In the DCS group we do research on sensor networks. Currently the focus is on security and reliability. We have a network of 35 sensor nodes that is used for experiments and demonstrations. The one in the picture is one of them.
Master projects
Projects will be part of a bigger project of the Distributed Computing and Systems group. We will assist the participants that would enjoy the research environment of the group.
There are a lot of master project possibilities in the area of sensor networks including:
- Geographic localization
- Clustering and membership
- Visualization
- Mobile basestations
- Attacks in sensor networks
Back to Andreas Larsson Back to masters projects