I am trying to prototype a sensor + location reporting chip that will do the following:

1. Sense if a object is present over the top of it (a vehicle to be specific)
2. Reporting the location of the chip (Not of vehicle)

The second option may be hardcoded into the chip and should be reprogrammable. These chips would needed to be installed in large numbers and there will be several such chips installed in close proximity. Each will report its own location to a centralized server (via wifi?)

That centralized server will then send the locations and busy/empty slots to a remote server which will then update some database.

I know the above description is very broad in terms of technical aspects but I need a starting point. Another thing to consider here is that I need to keep the cost of such chips lower considering that there will be 100's of such chips needed.