Xbee Long-Range
Hello,
I would greatly appreciate any answers to the following questions. I am fairly new to the world of microcontrollers but i have learned quickly and want to embark on a rather large project of building a UAV. First though i need a smaller task to create a GPS tracking device that i can communicate with via radio. The tracking device would be placed in the payload of a weather balloon to be tracked so it can be retrieved for landing-i can do this with a cell phone but would like it if i could build my own device to get some experience.
First:
The Parallax Xbee modules do not have the range i need for my project-is there any way to build a signal amplifier?
Second: How hard is it to connect a Xbee to a BASIC Stamp module and set it up to transmit the data from a GPS module?
Third:
Can a Xbee module remotely turn on and off a simple switch that is isolated electronically from the BASIC Stamp? Could I use a Digital Potentiometer?
Thank You!
-jakethesnake
I would greatly appreciate any answers to the following questions. I am fairly new to the world of microcontrollers but i have learned quickly and want to embark on a rather large project of building a UAV. First though i need a smaller task to create a GPS tracking device that i can communicate with via radio. The tracking device would be placed in the payload of a weather balloon to be tracked so it can be retrieved for landing-i can do this with a cell phone but would like it if i could build my own device to get some experience.
First:
The Parallax Xbee modules do not have the range i need for my project-is there any way to build a signal amplifier?
Second: How hard is it to connect a Xbee to a BASIC Stamp module and set it up to transmit the data from a GPS module?
Third:
Can a Xbee module remotely turn on and off a simple switch that is isolated electronically from the BASIC Stamp? Could I use a Digital Potentiometer?
Thank You!
-jakethesnake
Comments
However i would rather not deal with cell networks-any ideas how to at least double the range and keep it cell network free?
These modules should do a lot better in an open area. I'm not so sure about getting a full 14 miles out of them. They should work better if one or both units had a directional antenna.
It would be fun to get a couple of the XTend modules. 40 miles! Now were talking.
Duane
If _all_ that you want to do is to send GPS information from an XBee, it's possible to directly connect the GPS output to the XBee's data in line, and go without an onboard computer of any sort. The rather big downside of that, though, is that it will transmit almost constantly, which uses a lot of power. Your power supply will need to be pretty significant.
Here is some information on how to set up an XBee so that the digital state of a pin on the transmitting XBee will be reflected in the digital state of the corresponding pin on the receiving XBee:
http://www.ladyada.net/make/xbee/arduino.html
That's a start for your "switch" question.
-jakethesnake
As you said, a UAV is a "rather large project." I think a Basic Stamp is going to be hard pressed to do everything you'll need in this project. You ought to consider using a Propeller. Dividing up tasks among the eight cogs makes writing complex programs much easier than using a single core uC.
Duane
-jakethesnake
They were using a Xtend module. It didn't have enough range to allow tracking the payload all the way to ground (I think they lost their payload).
My suggestion is to get a ham radio license. You'll probably need it for a radio powerful enough to meet your needs and you'll probably learn a lot more about radios and know which one to use by the time you have your license. (I've been think of doing this too.)
Duane
-jakethesnake
Alternatively/additionally consider a high-gain receiving antenna (yagi or dish), but that requires careful aiming (given you have recent GPS location data its an exercise in applied geometry 8). Gains of 20dB or more are readily achievable, and since this is purely a line-of-sight situation that translates to ten or more times the range.
Be careful when transmitting down to the ground that the aerial is oriented correctly (a vertical dipole has nulls in the vertical direction). The polarization of the transmitter is going to vary as it turns, which will again cause nulling (the solution to this is using helical antennas).
You can make it out of a soda can: http://solarstatus.com/?p=58