HOBO Testing and Data

Hey everybody! Testing and preparations for Malta have continued at a rapid pace here at Cal Poly. We have now deployed our new Onset HOBO Conductivity and Temperature datalogger twice, and captured some great data. This data is going to be sent to Ian, who will be constructing some great 3D visualizations of it. Prior to doing so, however, the HOBOware software included with the datalogger can be used to quickly observe trends from the offloaded data. Here's a couple of plots generated with the HOBOware software:

The above plot was made with data from our testing session on the 16th of February at the PCV pool. The extreme drops in the conductivity readings (solid and dotted gray lines) relate to when the sensor was briefing pulled out of the water for various reasons.

This plot contains data from our most recent testing session, February 23, also at the Poly Canyon Village pool. One element of this plot which I, personally, did not expect to see is the battery voltage level (straight green line). This provides a level of assurance regarding the lifetime status of the logger, as well as the reliability of the measurements. When the battery capacity begins declining, the supplied voltage will begin to droop below the nominal value of 3.6V, indicating that the measurements may no longer be 100% reliable, and we will soon have to return the HOBO to Onset for battery replacement and recalibration.

We are planning to deploy the ROV one more time before our departure for Malta, but may not deploy the HOBO in order to conserve the limited battery life of the logger. Early data captures are indicating that the HOBO system will fulfill our needs, and provide reliable data.