Yes, the Arduino.
I assume that I installed the software correctly but had no instructions
and had to do a bit of digging.
My PIC worked right away getting the Cal constants then I had a few
problems with the 64bit math and had to use floating point which worked but
I kept seeing drift and needed a reference to see that my program was
working. I switched to an Arduino but the drift just keeps getting worse.
It has been off for awhile so I will add the last runs and a new one after
several hours rest. It seemed to recover but needs more like days to do so.
Notice the pressure drift has accelerated even though there was no power on
it (or the Arduino) for several hours. Notice the time column and notes on
what was done. The sensor was in about an inch of water the whole time.
Remove and allow to come up to room temperature
Barometer Time Temp⁰C Pressure mBar Depth m Altitude m
1035 14:41 29.49 710 -3.10 2899
Place in 25⁰C water at 14:48.
1035 14:50 30.49 699 -3.22 3022
Water 23⁰C 14:55 30.03 692 -3.27 3101
1035, 21⁰C 15:21 28.86 672 -3.48 3330
1035, 21⁰C 15:30 28.94 658 -3.62 3494
1035, 21⁰C 15:55 29.09 632 -3.90 3818
Unplug Arduino for cold restart
1035, 21⁰C 16:00 29.12 629 -3.92 3843
Unplug Arduino for several hours
1035, 21⁰C 19:25 28.58 601.00 -4.21 4179