My name is Manuel and I'm from Copenhagen, Denmark. I've been asked by various municipalities to develop a system which I am not to talk about yet unfortunately. What I can say is this:
I need a "device" with which (either include or with which i can interface a IR sensor) I can perform measurements (distance) ranging 20 to 150cm top. This is done outdoor, but inside an object. This device will have to be able to send data to a centralized computer (or web server) running in the city hall.
I thought about 2 scenarios:
Scenario 1) We take a small municipality area, which will be divided into sub areas. Each of these sub areas will have MANY of these 'devices' (which have a long range WiFi ) and probably some routers once in a while for each subarea in order to more or less map the all municipal area creating so a kinda virtual network (or is it just a straight LAN? :D) (Municipalities in Denmark are not very big--> 5 1/2 milion people live here, no mountains, not crazy buildings etc so not much interference or problems that these could cause).
So given the setup we will probably be able to just use WiFi to send information to a centralized computer in the city hall. (can the data that the sub-area router gathers, be forwarded to another router and forwrded again to the centralized computer? i would think so).
Plus: -Everything would go on WiFi, easier and fast sending information and we wouldn't have a whole lot of information possibly bombarding our server.
Minus: -More expensive (MAYBE???) than scenario 2, due to Routers costs -Introduce a single point of failure, so in case the router has any sort of problem all the devices depending on it won't be able to send info to the centralized server.
Scenario 2) Have a device into each object without having routers around, and use GPRS to send data (can I send this data to an ip corresponding to a webserver running in the city hall?) Can someone please briefly explain me how sending data over GPRS would work? Do I need to install a Sim card on each waspmote and therefore paying the traffic data this way, or how?!? I'm sorry but i lack of knowledge in this matter.
Plus: Maybe cheaper??
Minus: Might be more hard sending data to the server.
I would GREATLY appreciate if you guys could help me out on this, I really need.