dannable:
First of all, an excellent article on power saving by Nick Gammon:Gammon Forum : Electronics : Microprocessors : Power saving techniques for microprocessors
If you use a 3231 RTC you can put everything to sleep, turn the SIM900 off, etc. The RTC can wake the microcontroller on an interrupt, in turn that can turn everything on. Once all is up and running send the information, reset the alarm, turn everything off and go back to sleep.
Thanks dannable,
I've ordered my parts and they arrived a couple of days ago. I've been tinkering around with the DS3231 and its a great RTC! and the temp sensor was an added bonus! My SIM 800L also came, although I am now wondering how I hook it up, as the arduous 3.3v and 5v pins wont supply enough amps to meet its needs.
Basically it needs a steady 3.7 to 4.4v at 2Amps, so I am going to have to get an external battery that meets those needs. I was thinking of going for one of these rechargeable external batteries with 2 USB ports that can output 2 amps, the first usb port i'll use to power the arduino and the other sensors I ahve attached to it i know that the arduino can power and the other port i'll use to power the SIM800L. I think this means I am going to have to step down the voltage from 5v (from the second usb port) to 4.4v, which I think means I need a DC-DC converter buck converter?
I get everything up to this point, if what i've said above is right, i'm not sure now though how I can use the RTC to power down the SIM 800L if its constantly connected the the buck converter, do I need some sort of switch between the buck converter and the SIM 800L or can I power down the 800L directly from the arduion?
Hope this makes sense,
Thanks.
Anton