To test our device’s processing accuracy, we hooked up a voltmeter across the sensor and converted that voltage to an expected pressure reading in excel. We then compared those readings to our actual pressure measured by our device. As seen in the graph below, the device performed quite well, and the small amount of deviation present, we mostly attribute to the sensor’s visible creep.
Overall, we accomplished the three main objectives for this project: reduce the size of the sensing device, be able to easily switch out sensors to test, and minimize the cost of the sensing device. The original semiconductor analyzer weighs around 40 lbs and measures about 13”x16.5”x22.6” compared to our final product which weighs less than a pound and measures about 1.5”x3.5”x4.5”.
We have a few ideas for further improvements that could be made with more time:
- A custom mobile app that displays the sensor’s readings in a graph over time.
- Automatic calibrating of the voltage divider, which could be done with several resistors of different sizes and some independent logic in the micro-controller.
- Some cosmetic features on the device, such as an on/off switch, a velcro mount for the battery, and a rigid carrying case.