REU student: Sterling Prince
New Jersey Institute of Technology
Nanotechology lead to significant miniaturization of sensory devices
that introduced new challenges in sensor integration and unfolded new
opportunities to advance the sensitivity and extend the range of potential
application of sensors. The selective metal oxide gas nanosensors used for
exhaled breath analysis behave electrically as a resistance and therefore
a specialized instrumentation is required to obtain readouts. To achieve
the high sensitivity required for breath analysis, readout techniques are
required to address inherent properties of the sensor, particularly their
large baseline resistance that can be few orders of magnitude higher than
the actual sensor response, large variability of base resistance across sensors,
and the drift in base resistance over time at a different rate across sensors.
Current instrumentation techniques developed for resistance measurement of chemical
sensors have not provided the baseline tracking and cancellation that is needed to
permit high resolution readout of the actual response portion of the sensor’s
resistance. The student is working on the design of a portable handheld breath analyzer,
comprising gas sensor array that interfaces readout circuitry. Baseline tracking is
implemented through addition of the voltage digital-to-analog converter (DAC).
DAC supplies an adaptable current through a sensor providing the low power
and high precision implementation for different base resistance.