I am currently working on a project that I could really do with some guidance on. What I want is to be able to ring or send an SMS message to my arduino, then the arduino replies with its GPS co-ordinates. I have seen someone do it before however I can't seem to find the tutorial anymore anywhere!
My hardware is:
SIM900A GPS/GPRS module.
These units will be 'disposable' if you like. However ideally the battery life could do with lasting up to a year, so i did think of using the sleep function so the arduino only switches on every hour, on the hour? Also, what kind of battery could I run this system on that has the longevity but without frying the board?
I hope you don't think I want the earth, however I am happy with one step at a time!
Thanks in advance guys!!
You will have to build special circuitry to get even a few days of battery life, and you probably won't be able to do that at all with a Mega, unless you use something like a lead acid battery.
Start by learning about power saving techniques here.
I'm only using the MEGA to get the basics set up. Its just one I had already, thats all!
Think you might have a couple of problems with the Sim900A module.
First, not aware it can do GPS, you need a module like the 908 or 808 that have it built in.
Second, the 900A is firmware locked to only operate in some far east countries.
Third, all those board use 2G only, some countries have ended 2G support, so you may have to use a 3G compatible module with GPS.
I put another post up here with what you can do to get the power consumption on a standard Mega as low as possible.
One problem you will have is that the 3G board itself uses a lot of power, but if you turn it off you will lose the ability to receive an SMS message or incoming call to trigger the response with the GPS co-ordinates.