The latest addition to my coin cell nodes, a PIR motion sensor based on the Ebyte NRF52805 module.
The PIR sensor is a Senba S16-L221D-2. I'm measuring around 24uA, which is higher than advertised, but with the 6-7uA from the NRF52805, should still get me 3-4 years on a single 2477.
@BearWithBeard Well there are more things in play. Making assumptions now. Most people don't want to read the trouble shooting section, they just want to be helped quickly. And from a usability perspective written documentation isn't the most optimized form of transferring knowledge. Because it is almost impossible to write things in such a way every one can understand it. A simple comic on radio trouble shooting might help more people. But again, that is just assumptions.
I always try to find the solution myself. But have seen people asking question that were documented well. In this an other forums.
@willemx
Remembering now, the undervoltage and overvoltage protection could both be put under the MCU's control, in which case you could get by with just a diode, or equivalent. It wouldn't be as failsafe in the sense that an unforeseen bug in your code might defeat it, but it could be done. In the end, I'm not sure that the chance of encountering a failure in software is necessarily any higher than that of encountering a failure due to defective hardware.
Alternatively, you could put two cells in series, and in principle that would eliminate any chance of overcharging. With that configuration, if you used a 5v solar panel instead of a 6v, then you'd also eliminate any chance of burning out the atmega328p and wouldn't need extra hardware to ensure against that.
For that matter, you could stick with one cell and just use a 3.5v solar panel. With just that one stroke you wouldn't need anything extra to guard against overcharging the battery or over-volting the atmega328p.
That's what makes embedding solar such a fun problem--depending on the use case, there are such a large number of different ways to solve it. So many that the real game is in comparing the trade-offs.
I use these: https://www.aliexpress.com/item/32855681042.html Well, they work, but profile is not the best for dupont (2.5mm). But for their price it's ok.
YEFYM SN-2549 crimping pliers 0.08-0.1mm2 28-18AWG 2.54 spring 2510 terminal =SN-28B+SN-01BM eupop style wire crimp tools
$15.69
