Thanks for the guidance. I have a friend to do the SQL Database for me, so that shouldn’t be a problem.
These units will go in runoff retention ponds at cattle feed yards to monitor water levels. Most of the facilities don’t have wifi access, so the WIFI Xbee radio isn’t really an option. The GPRSBee is a good option, but I am looking at about 150 units. The best cell phone network out in my area is the Big Red One. They charge way to much to use their network. We do have AT&T, but the service is sketchy in most areas. Do you know of any lower rate sim cards that may work? These units will only wake one time per day then go back to sleep. Data transmission will be really low. I would like to use GPRSBee if possible, that would allow me to avoid using a mesh networks with XBEE radios.
I am very interested in seeing the photos of the units you built.
Again, thanks for the information.