After two months of on and off development, we decided to put this project on hold. The entire code base for our system is in place - with minor adjustments and quality of life improvements, it is a finished product. Our hardware, however, is not up to the task. It was and still is great for prototyping and testing and we learned a lot in the process, but the parts used are simply not tailored for this design.

We came to a conclusion that, should we continue to develop the hardware, a custom-made pcb with strict power control is a must. Design as it is is simply sub-optimal and we can do better. We will try out the new v3.1 of the stalker board though, as an intermediate step.

A big part of why our tests didn't go as far as we thought they would turned out to be the base for it all - the Seeeduino stalker. A while back, they offered a great deal - v3.0 stalkers 70% off. That's when we got this board. It was sitting in the office unused until we picked it up for it's fabled efficiency in outdoor applications... But it turns out there's a story behind why they were 70% off - a series of poor design choices including a cheaper RTC chip without temperature compensation (quite disastrous for any long-term applications though that doesn't bother us too much because we can readjust it from the server) and a poorly optimized regulator which burns over 3mA under certain loads. This burn happened to hit us while the device was in idle state, greatly hurting its battery life.

Reading around about the stalker 3.0, it turns out we were not the only ones unhappy with what they did with the board. It's not terrible, but at some point, we will have to part with it for a better solution.

Graph below shows our enthusiasm for hardware used.

It actually plots battery charge % over 3 days. Green humps are times when battery was being charged by the solar cells.