Master Thesis - Past Projects - Abstract
Continuous Measurements of Core Body Temperature using Body Sensor Networks
Long-term body temperature measurements for research and diagnosis are currently done in hospitals or specialized research labs. This method has several drawbacks: the use of wired ob- trusive sensors (e.g., rectal probes to measure the core body temperature) may be uncomfortable for patients. Furthermore, situations recorded in laboratory settings do not reflect reality as patients are not subject to their normal living environment. Furthermore, it is labor-intensive to regularly check upon patients and care for their well-being. Using small wireless sensor nodes in a body sensor network to measure body functions, one can mostly offset the limitations listed above.
For this work, we have developed a wireless sensor node that uses an infrared thermopile as a sensor to unobtrusively measure the core temperature at the tympanic membrane. Due to their construction, these sensors are heavily dependent on the ambient temperature in the surroundings of the sensor packaging. While this does not affect their use in single-shot measurements (e.g., using an ear thermometer), it poses a challenge for continuous measurements, as common living environments do not have constant ambient air temperatures and people frequently commute between different places. These conditions may offset measurements significantly, an important problem for medical applications that require high accuracy.
In this work, we employ infrared thermopiles in a body sensor network and characterize their behaviour in various situations, especially in the presence of varying environmental conditions. Based on our observations, we describe methods for post-processing measurements in order to compensate environmental changes and hence get results reflecting reality more closely. Our evaluation shows that these methods can offset the infrared thermopile’s weakness but need further work to achieve the degree of accuracy that is needed for medical applications.
Keywords: body sensor networks, contiki, interpolation, masking
File: Click here to download/view the thesis
Author(s): Peter Hegen
Contact: Simin Nadjm-Tehrani
Click here to return.