I'm looking to build a battery powered NodeMCU (using Lua) for simple data logging. I want to use rtctime.dsleep and I don't want to have to turn on the radio stack each time I take a measurement. So the plan is to wake from sleep, take a measurement and save it to a file.
I have this working fine and I thought that downloading the data file to another computer (Raspberry Pi in this case) would be easy. Unfortunately it is not. This is because the file is bigger than can be held in a string AND the fact that you can't do one thing at a time. I have tried HTTP PUT and POST and websockets, but they all try to send multiple requests at once.
So, my question is: Is there a reliable way to download a large file from the NodeMCU to another computer?