The Quest For Sun

AMOS has been mostly on its own for the past week in Kelly's Creek, near Woolastook Park. Hannah and I deployed it on Saturday morning, and tested out the LiDAR "avoidance mode". Once it did seem to work, but another time it did not, as AMOS plowed directly into the side of the canoe. I believe I was able to correct a software bug related to that this morning, but have not had a chance to test it out yet. That day was also very windy, and AMOS overshot a couple of its sampling waypoints and had to return against a strong west wind with gusts > 20 km/hr. Here is a map showing the track (in blue) that it followed before it eventually ran low on power and drifted under some trees on the south shore:

Even though the next day was sunny, it was not able to charge at all under the trees on the south bank of the river, so I took the kayak out and towed it to the north shore, letting it sit there for about an hour and a half to properly charge in the bright noon-day sun. Then I set it to continue on its way, where it traveled to the far end of the waterway, before shutting off its propeller at the planned time of 3 pm. After I got home, I opened a terminal connection to it, to discover that it had once again drifted to the south shore. So I found a place on Google maps on the north shore well away from houses, and created a short script to send it to that spot, 500 m across the water. The day after that was quite rainy and overcast, and AMOS never really charged very much, so again through the terminal connection and various file scripts, I set AMOS to mostly drift around, just using the propellers to stay away from the shoreline. It eventually covered 2.5 km, but that was over about 3 hours. Eventually it came to rest against someone's dock for the night:

I tried to steer it away from the dock, but the battery was too low to drive the servo controlling the propeller direction, so it just kept ramming itself into the dock instead. Nothing to do but leave it for the night, and hope that no one minded I guess. During the night, the wind must have taken AMOS a few hundred meters northeast to a less populated area. The battery must have gotten pretty low during the night I think, so I just let it charge up today, which was only partly sunny:

9:00 am --> 11.454 V
10:08 am --> 11.666 V
11:19 am --> 11.810 V
11:59 am --> 12.022 V
5:30 pm  --> 12.25 V

I was a bit surprised that it didn't charge up to more than 12.25 V by 5:30, as the afternoon was much sunnier than the morning, and from what I could tell from the boat's camera, it was in a spot on the north shore without noticeable shade. Here is the view from the camera when the boat was facing west:

 Normally in bright sunshine all afternoon, I would have expected to see the battery voltage climb up to over 13 V.

I added some software to AMOS to define optional "safe" locations in the text script files. These are locations where AMOS will head to when its battery starts to get low. I tested it out this evening and it seemed to work, choosing the closest safe location, although AMOS was pretty close to that point already, so it wasn't a very hard test.

Tomorrow looks like it's going to be rainy again, so if there's time, I think I'll make a trip out to retrieve AMOS and modify it to switch off power to the cellular hotspot during sleep mode. Right now it's just on all the time, which could be wasting a few watts of power at times when I can't even communicate with the boat anyway.