I am thinking of using a sim900 module but I think I need to add a gps module as said in post 2
Depending on your application, perhaps consider using a small cheap android phone as the tracker, or as a development bed. Has advantages:
- price (there are always phones on special here for $29, and often less: I bought 4 a few months back at $14.50)
- speaker (eg, for out-of-area alerts)
- accelerometers (eg, fall detection, acceleration, braking, impact)
- camera (eg, as a dash cam)
- flexibility, via programming with B4A
- supply continuity (vs trying to get compatible modules six months from now)
- flexible interface via touch screen
Disadvantages:
- size
- overkill