long range am tranciever

I've dont a lots off searchin on Google But i can't find anything that matches what i want to do. And just to start off. Im posting this on my cell becuase of the lack of internet at my house. My current proje t im working on is dealing with a rover. On board gps. Usrf. Strobes relays etc. I want this to be almost autonomous. Recieving gps coordinates and traveling to the just to start. But im concerned with communication since i can run a two mile usb cable i got to go wireless. Dont think xbee would go that far (pluss im cut for price). Wifi is definently not going to work. So im wondering if an am radio signal would work... Maby sending morese code back and forth. There are alot of unused am frequencies around me so fcc shouldnt be an issue. Anyone else got any ideas? Are there any alternatives. Btw i would like not to get an arduino mega. I have the 13 pin varrient.

There are alot of unused am frequencies around me so fcc shouldnt be an issue.

Unused and free-to-use are not the same thing.

Dont think xbee would go that far (pluss im cut for price).

Some models will. The XBee is more than a radio. It implements a protocol which includes re-transmission of failed data. It implements a lot of the error-handling already that you will need to implement as part of your protocol.

ok so with xbee. i may be hard pressed for pins. i got to acount for two gps pins. three relay pins. pins for two motor channels (using an h bridge. should be 6 pins( 3 for each motor)). a thermister. a voltage divider in from battery. and a photo cell. is xbee going to fit

Are you currently using pins 0 and 1 for anything (other than Serial)? If not, XBees will work just fine, since they replace the physical wire between the Arduino and the PC that currently provides Serial communication capabilities.

Will the gps work on pins other than those two? Thats what i would be using them for

GPSs work well, generally, with software serial ports, as provided by NewSoftSerial.

The reason i was wondering about am is because its a good range and ramsey electronics sells an am transmiter that is fcc legal. If i could find or build a circuit that would recieve the signal i could do one way communication to the bot. Essentialy i could just send an init tone or morse and then send a morse of the coords. What would be cool even is if i could find an am broadcastr for arduino. Dont really want to spend 100 on two transmitters. That newsoftserial really seams like a God send. It would work great. So am i going to have to purchasw two xbees anda new arduino board? Thats about 100 dollars just for communications... Sigh

because its a good range

With a big transmitting tower, yes. With a little antenna on a battery powered car, maybe not.

ramsey electronics sells an am transmiter that is fcc legal.

Over what frequency and range. Often these transmitters have (very) limited range. At what price?

If i could find or build a circuit that would recieve the signal i could do one way communication to the bot.

Your earlier requirement was for the bot to send back GPS data, and for you to be able to control the robot remotely. Has this changed?

So am i going to have to purchasw two xbees anda new arduino board? Thats about 100 dollars just for communications...

You probably don't need an Arduino locally. This: http://www.sparkfun.com/products/8687 and a XBee on the receiving end, and an XBee and shield on the Arduino on the robot are all you need.

USING am i would use a work around and that was it. But thinking of all this and the support that xbee has i would be foolish with my expierience and knowlegde to venture into that other realm.xbee is a great choice. I was under the impreasun though that the shield came with xbee already installed? If not price is going to raisw and i dont like that...

In the US there are no "FCC Legal" transmitters that will work more than a few hundred feet AND allow you to transmit data. When you used the term FCC Legal I assumed you meant legal to use without a license. Someone can correct me if I am wrong, but the legal limit without a license is 100milliwatts. There are certain bands (CB, FRS, GMRS) that allow more power, but some of these still require a license and still don't allow data.

So there is no FCC Legal unlicensed radio device that will work for your application if you need the distances you mention.

If you want to operate legally you have 2 options that I can thank of.

  1. Get a ham radio license and use the bands that are meant for this. If you can build a project like this you should be able to get a ham license without too much effort.

  2. Use a pre-paid cellphone. You can communicate cheaply via text messages or for a higher investment, communicate with data over the internet.

Your right. The transmitter i was talking about through ramsey was for a fourth mile... 50 dollars. And this projects doesnt seem that hard to me. Am i missing something here? Other than the arduino the two biggest comonents are the h bridge and the charging circuit for solar. I think ill stick with xbee. Last time i checked a ham radio operator license was almost $200. I could afford to get the 40 mile trancievers for that price. But though thaks for your input. I have gotten my parts list and a 125$ price tag from spark fun 8-)