OK, which part?

roughwire

I was wondering, lets say i just wanted to control a robot from like up to 1500 ft away, by simply using the arrow keys on my PC's keyboard; what whould I need? I dont really know the bennifits of Blutooth compared to RF... P.S., I also wanted a camera that has that range too. Thanks...


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MIKE

Mike Green

There is more than one part to your question:

1) How do you transmit control information from the keyboard to something else?

2) How do you get the information over some kind of wireless link to a robot?

3) How do you control the robot with the information received over the link?

#1 requires some kind of program. Usually, you'd use a terminal emulator like
HyperTerm or some other similar program that would send control characters for
the arrow keys to some kind of standard serial port.

#2: The easiest system to use is xBee. To the PC it looks like just another serial
port and to the robot, it can look like a wired serial connection. There are some
higher power units that have the sort of range you're talking about. Bluetooth
is not intended to be a long range system. It's limited by design to about 30 meters.
Parallax's 915mHz transceivers have built-in error correction, but don't have the
range you want. Some of the longer range systems don't have the built-in error
correction.

Cameras have other issues related to the amount of data they need to send:

1) What kind of camera? How big an image? How many pixels? Color or B&W?

2) What kind of processing will go on at the robot?

3) What kind of processing would go on at the PC end? Is this just for display on a monitor?

4) Cameras and high speed links usually need a lot more power than low speed data. How much power is available?

Do a web search for wireless video cameras and you will find lots of vendors for systems that will transmit an image
anywhere from a few hundred feet to a sizable fraction of a mile depending on cost and power available. This is usually
provided at the receiver in the form of a video signal which can be displayed on a TV or processed through a video input
card or adapter for display on the computer screen. It's much more complicated to get the video data for analysis by
a program.

Steve Joblin

at 1500 feet, you are way out of the range of bluetooth... I would look at XBee-PRO™ ZigBee OEM Modules... they have an outdoor/RF line-of-sight range of up to 1 mile (1.6km) and are pretty inexpensive... Sparkfun sells a breakout board for it (http://www.sparkfun.com/commerce/product_info.php?products_id=8276).

Sparkfun also sells the LN96 915MHz Long Range Modem that has error correction and an output of 500mW with a 1500m range... http://www.sparkfun.com/commerce/product_info.php?products_id=559

uxorious

I would recommend 802.15.4 (2.4Ghz) as well. The Xbee modules are a good/easy way to start. Definitely spend the extra and use an external antenna via the RPSMA connector to eliminate the range variable.

We build a product based on the Telos B Mote designed by UC Berkeley that performs above all "published specs" when used with an external antenna. You could easily extract the radio portion for use in your circuit, but that would require some PCBs, etc.
www.tinyos.net/scoop/special/hardware

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~~ dRu ~~