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Tests
Below we detail some preliminary tests conducted on three MyPart prototypes:
##Outline
- Smoke tests overview
- Smoke test 1
- Smoke test 2
- PSL sanity check
- PSL voltage threshold test
- Outdoor test overview
- Outdoor test
- Future Tests
One of the particle sources we tested our sensors with was wood smoke. The size distribution for burning wood tends to be in the sub-micron range, which is particularly important to sense accurately with respect to human health. In addition, these particles are easy to generate and decay naturally after being injected into our chamber, which allows us to collect a large amount of data across a broad range of concentrations.
We ran two tests with smoke in our testing chamber to find the correlation between MyPart sensors and commercial sensors. To produce smoke, we set fire to a wooden skewer, blow the flame out, then waft a small quantity of smoke into the chamber before sealing the lid. A set of fans inside the chamber mix the particulates. The sensors run an automated test sequence, all sampling once every minute, until the particles in the chamber decay to ambient concentrations.
[plot] [Table]
We see very strong correlation between the three MyPart sensors and the MetOne. In addition, we see very strong inter-device correlations between the MyPart sensors.
Sensor 0 is seeing only 30-40% of the particles seen by the sensors 1 and 2. Of the three sensors fabricated, sensor 0 also had the highest noise floor. Though the source of the higher noise is currently unknown, it is likely the cause of the decreased sensitivity.
[plot] [table]
In this smoke test, we again see very good correlations between the MyPart sensors and the MetOne, as well as between other MyPart sensors.
In addition to being noisier, the noise floor for MyPart 0 also seemed to be inconsistent. The noise floor for MyPart 0 increased before this test, and the voltage cutoff for a sensed particle had to be increased accordingly. As a result, MyPart 0 saw less particles compared to MyPart 1 and 2, but still showed good correlation versus the MetOne.