Sensor modules for wireless distributed sensor networks
Andre Pin Chun Lee, Charles F. McConaghy, Julier Simon, W Benett, Leo H. Jones, J Trevino · 1999
A national security need as well as environmental monitoring need exists for networks of sensors. The advantages of a network of sensors over a single sensor are improved range, sensitivity, directionality, and data readability. Depending upon the particular application, sensors can be acoustic, chemical, biological, thermal or inertial. A major desire in these sensor networks is to have the individual sensor and associated electronics small and low enough in power that the battery can also be small and of long life. Smaller, low power sensor nodes can allow more nodes per network. A typical network for security applications is depicted in Figure 1. Here a number of sensor nodes are deployed around a central hub node in a star configuration. In this scenario the hubs communicate with each other and ultimately relay information to a satellite. Future networks might follow this scenario or some other network architecture such as a hopping network where individual nodes communicate directly with each other. The focus of our research has been on development of the small low power nodes and less on the overall network topology. However, some consideration of the network must be given when designing the nodes and some consideration of the nodes must be given when designing the network. An individual sensor node contains not only the sensor but also the sensor interface electronics, analog to digital (A/D) converter, logic, RF communication link, antenna, and the battery. Future nodes will also contain some form of signal processing to allow more sophisticated network architectures. The FY98 goal for this project was to make a sensor node with a physical form factor of a 2 inch x 2 inch x 2 inch cube.