Long distance wireless communication [closed]

Question

I have a remote starter in the car that I'm trying to start from a longer distance than originally conceived for. I have found a way to modify a cell to start the car when getting ringed, but that involves giving money every month to the phone company which I'd like to avoid.

Does anybody know a simple solution to transmit a reliable signal over few hundred meters (through many building walls and the concrete of the parking garage) to a receiver in the car? Ideally I would like to get a ping back that the car has started, but this is optional. If more logic is involved I can use Arduinos on both sides.

I saw somebody mentioning modified walkie-talkies - this will probably be the solution if I can't find anything smaller (I would like to have a small remote starter that would fit in a pocket, but not sure if that would go through all the walls)

Edit I'm looking for a solution that is not very expensive and not very large in size (so I can keep it in my pocket ideally), battery powered, in order to be able to send a start signal few hundred meters away through concrete walls. I don't need high throughput, just few signals. Also not too complex technically so that somebody with limited knowledge (me) can build it :)

Answer 1

You should search for wireless modems. There are lots out there, including:

• UM96 (500m range)
• XBee Pro 900 XSC RPSMA (28 mile range)
• Digi XTend (40 mile range)

(ranges given are under ideal conditions)

You'll need to have a microcontroller (such as the Arduino) on each side to control the modem. You'll also want to have encryption so that you don't get malicious hackers turning your car on and off. Some modems (such as the XBee's and XTend) implement encryption in the module itself.