Wifi Help...Please Help!

Others will probably answer with 802.11 solutions. I don't think it's necessary or desirable for a robot that will probably loose contact at various points.

That's why I suggested a mixture of technologies and separating the video from the control functions. The video is essentially one way from the robot to the operator. No need for high performance in both directions. With NTSC video over 2.4Ghz, you'll get 30 frames per second in almost real time. With digitized video from a USB camera or NTSC digitizer card over 802.11g, you'll get somewhat less depending on distance, error rate, interference, obstructions, etc. Look into remote video such as:

Actually, this would be a good time for some hair splitting. In my never humble opinion, a robot is an autonomous device, not something controlled by an operator. I don't know how much control you plan to have over this robot. Does it patrol over a specific path (controlled by GPS or buried wire)? Or, is it run by an operator with a joystick? If the later, it's really a radio controlled vehicle. There are lots of commercial and amateur robotics web piles on the internet. Methinks some Googling might be a good idea to see what others have built.

Well, I dunno about this one:

Trees are usually fatal to 2.4Ghz signals. More power (signal booster) is helpful, but methinks a lousy solution. If you're going to go 2.4Ghz, methinks deploying some store and forward repeaters along the path will allow you to maintain contact, without resorting to directional antennas or illegal power output.

The real question is how much will they help? A transmit power amplifier is really nice for getting a signal *TO* the robot. However, without a similar power amplifier on the robot, there's no guarantee that the signal *FROM* the robot can be heard. In general, such amplified solutions need to appear on both ends of a wireless link.

Incidentally, that's what's nice about higher gain antennas. The improvement appears in both directions, not just one.

Hmmm... telemetry doesn't require quite that much. Digitized video at about 2-5 frames per second will fit in 150kbits/sec depending on the size of the image and compression method (MPEG-1, 2, or 4). Bandwidth for command and telemetry is next to nothing.

Anything else on the island nearby that uses 2.4Ghz? Cordless phones, microwave ovens, wireless links, wireless video, security cameras, wireless web cams?

Well, it's up to you do multiplex all the video and telemetry. A small PC (laptop?) can do that quite easily. See:

something rather close to what you're planning. I've always wanted a laptop that follows me around.

At 900MHz I'm familiar with the following radios:

are others. Note that the specified ranges are in miles. The catch is that at 900MHz, the band isn't wide enough to support high bandwidth. Association speeds vary from 200Kbit/sec to about

3Mbits/sec. Thruput is about half of that. Interfaces are either serial or ethernet. Programming these radios is a challenge. Basically, it has the same range and coverage as an 800Mhz cell phone.

I think you can, but it would probably be too much work. I've built a tracker that will follow a model airplane or RPV with a 24dBi dish antenna. It's not trivial, but it can be done. At 1000ft, a pair of omni antennas will work. Methinks 8dBi on the robot and 12dBi on the base station. Keeping the antenna perfectly vertical on the robot will be a problem.

(select "Antennas Omni).

Sure. What kind of armament and weaponry?

I still suggest separating the radio functions.

1. Video over 2.4GHz analog 2.4Ghz link.
2. Servo operated radio controls as in a radio control model vehicle.
3. Use FRS/GMRS radios for intercom and voice communications.

Good luck on your golem.

Hello!

Thanks for all the replies. I really appreciate it.

I'll try to answer all the questions.

(1) There is cellular service. However, it's way to expensive.

(2) I don't "need" to use WiFi, any thing that would work is fine.

(3) I'd be mostly driving down in sort of a valley. Sometimes there'd

be line of sight, but there might be trees in the way sometimes too.

(4) Would having one of these products below help: (signal boosters)

(5) I'd be sending one video stream from the robot, and sometimes an

audio stream from and to it. Also, a few other data feeds, such as

battery level, MPH. I think I'd need about 150kb/sec.

(6) There won't be anyother robots to interfere. (no tournaments or

anything)

(7) 900mhz with 115kb/sec might work. What product(s) would I use to

send the video and commands?

(8) I don't think I could get directional antennas to work.

Hope this helps. Any other questions, just ask.

Thanks!