Field Report 2014-08-24: Assemble & Test all units

Re-assembling the units

Putting the Pearls back together again.

Life intervened while we were still mid flight to Mexico, making it clear that this trip was going to be much shorter than expected. We would have only 5 days on the ground instead of the planned 12.
I started re-assembling the new drip sensors in the car as soon as we left the Cancun airport. With a 15 minute sampling schedule they would need a full 16 hours before data buffered in the eeprom would be written to the SD cards.  Later that day I put the flow sensors back together and loaded the final deployment scripts. With the flow sensors using a short five minute sample interval,  they only need 8 hours to complete a full cycle. While all the units had been tested at home, I always want to see at least one more successful run before a unit is installed into a cave.

One dead soldier before it even goes in the water

We had one dead soldier before it even went into  the water

The software for the unit with three accelerometers still needed some final tweaking, so I set to work on that (I had the epoxies clamped on that one till the last possible minute before packing) but it turned out that the ADXL345 would only read on the x & y axis.  As it was too late to fix the problem,  I just commented that sensor out of the code.  The resulting script will only give me data from the BMA180 and the BMA250 but that is still enough to bridge the data sets from our main installation site. Fortunately the three temperature pearl was running well, and I will be quite keen to see how those sensors differ in their behavior once the unit is in the actual cave environment.

Addendum 201409-10: Looks like I might have made a mistake with the ADXL345. Turns out that many of them are so badly calibrated from the factory that the Z axis is almost useless unless you change what’s in the offset registers. I live and learn.

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