Long Term Runs

Once the sensor was properly built, and a more sensitive plate applied, we took a look at how the sensor operated for longer (<5 minutes) periods of time. To do this, we built a script in using Go to monitor the sensor, record the output to a CSV file, and display/graph the capacitance overtime on a webserver. The code for this can be found in section \ref{843961}, which is contained in an attached file. The sensor showed a steady positive increase in sensed capacitance while left in open air for each of the tests run. As figures Fig. 3 and Fig. 4 show, the trend was consistent across multiple tests. Our hypothesis for why this occurred, which we cannot properly test, is that the capacitance plate, when exposed to open air in a non-controlled environment, will tend to gain free charges from the air, causing the increase in sensed capacitance. This would explain why the sensor, which is a measure of how long the circuit takes to reach a certain charge, would measure an upward trend. Interestingly, the sensor still operated as an accurate capacitance sensor with this observed anomaly.