I’m going to build a temperature logging system to monitor temperatures over the day in the little seedling raising greenhouse I build from a recycled window frame. I want to make sure I’m not over-cooking the seeds (which I think batch 1 is already crispy) so I want to measure ambient inside the box, outside the box, and in the soil in one of the seedlings; log this over time and check it regularly. Eventually this device might get promoted to
For temperature I’m going to use the MAX6675 thermocouple sensor and K-type thermocouples that I have for a coffee roasting project that is on hold (due to needing to build a much larger shed to store the roaster )
For power I hope to use Li-Ion 18650 batteries, charged from a solar panel. I might go to larger batteries (say a 6v gel cell) if I find I need to run a fan or a motor of some form to open the lid of the box and ventilate things.
I have a “12v battery charging solar panel” that I have no real information about - all I know is that it has some internal circuitry, it’s not a raw cell, as it has at least an LED that flashes when there’s sun out even if there’s no load on the panel itself. I measured it’s open circuit voltage in sun and it reported over 20v.
This will all be running a Panda with SD card.
This is just a thread to get input on the power aspects of the project. I have little/no knowledge of these aspects so I’m looking for ideas - thanks in advance for your comments!