I'm trying to build a little project (my first) with my Pi which is running Raspbian. I want to set up a camera on my piece of land where I'm going to build my house to take some time lapse photo's.
For this I'll set up the Pi with a camera and let it take pictures every one in a while. The Pi itself will be powered through a solar powered battery which should be enough to sustain it indefinitely (well, I hope). I think I've got this part covered.
As the Pi is going to be high up in a tree somewhere, I need an easy way to connect to it and download the pictures it takes.
I've come up with the following three ideas:
I've been thinking about setting it up as an access point (as shown here: https://www.maketecheasier.com/set-up-raspberry-pi-as-wireless-access-point/) and then downloading the files through an ftp server or something.
It seems like a good idea but I don't really want it to be hosting a wifi network the entire time since I'm only going to downloading the pictures occasionally.
I've also thought about the other way around: setting up a hotspot on my phone and letting the Pi connect to it whenever I'm around. But again, I don't want it pinging for a network that's not going to be there for 90% of the time.
Another idea would be to let it connect to a 3/4G network and just have it send pictures through e-mail, but again, this could be very power consuming.
Obviously, I don't want to go up the tree every time I want to download pictures so my question is: How can I remotely connect to the Pi to download pictures, in such a way that I don't have to physically touch it and that it doesn't use up too much power.
Ultimately, I'd like to know which of the above approaches is the least power consuming and, if possible, the most viable. Any new ideas are greatly appreciated as well.