Red Butte Canyon Monitoring
Wireless sensor networks are being used to enable the study of the watershed hydrology of the Red Butte Canyon area of the Wasatch Front.
Wireless sensor networks are designed for the advancement of basic science. Water resources research is one field in which wireless sensor networks offer significant potential for furthering our understanding of a number of fundamental issues. This field is particularly important for the western United States, where regions once affected only by limited precipitation and inter-annual climate variation are now being heavily impacted by land-use change and expanding human enterprise. In the arid to semi-arid Great Basin Watershed and adjacent territory (Colorado, Idaho, Nevada and Utah), the hydrologic system will be modified to support five million new residents with a projected total population of 16 million by 2030 (U.S. Census Estimates and Projections 2006). Effective water management planning requires quantification of interrelated hydrologic processes including precipitation inputs, stream flow, groundwater recharge and evapo-transpiration.
This research both advances the state of the art in wireless sensor network design and operation and answers fundamental research questions in the fields of water resources and hydrology.
In August, 2007, we deployed our initial sensor network in the Red Butte Canyon to measure stream water temperature along the Red Butte Creek. Ten Crossbow mica2 nodes are deployed along a 100 meter stretch of the creek, five with a thermistor temperature sensor placed in the stream. We use specially written TinyOS module for the purpose of establishing a multihop network and recording temperature data.
Thermistor temperature sensing
The mica2 sensor board (number 310) comes with a temperature sensor; however, we cannot submerge the sensor board under water. Moreover, we don't want to make significant modification to the board or make our own sensor board. As a simple method for temperature sensing, we remove the light sensor from the sensor board and replace it with a thermistor (NTC-153 15KΩ) on the end of a 6 foot long 2-wire cord. The thermistor and another onboard resistor form a voltage divider, and the ADC samples this voltage. Temperature can be readily calculated.
Sensors are currently being deployed in-building for code development and improvements.