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gps tracking the size of a nine volt

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rdmmdr

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hi guys

I just recieved two xbee pro modules and a droids usb adapter with a simple xbee board, i also got the "ls2003" gsp module.

Integration was as follows.

1.split the included 90 degree header in to four two segment units

2. solder the header two the usb board at the rx/tx port and the 3.3 volt ports.

3. solder the headers to the simple board at the rx/tx inputs and the 3.3 and ground

4. solder a nine volt clip / battery holder to the simple board at vin and gnd

5. take the cable that came with the ls20033, raid an old computer for the cables with the molex connectors on the end two strand is what you need. connect pins 1+6 to the positive and pin 2 to the gnd. connect pins 3+ 4 to the rx/tx.


6.put the solder iron away

7. plug the gps unit into the usb board/ the nice thing about this board it has pin out fo ttl level serial and 3.3 voltage

8. install the driver for the ubs board, see droids.it for the redirect. on my machine it installed a microsoft mouse drive that i had to disable in the control panel. Now your computer should talk to the usb module.

9. open up control panel and go to ports and make sure that the date rate is set to 9600

10. open minigps and set rate two 9600 with is the default rate for the unit and what com your computer assigned to the usb adapter. click connect and it should work. so at this point the gps is talking to the computer but it is not talking remotely

11. open x-ctu this is the config software for the xbee units. and close minigps since you wil be using the same channel

12. unplug the usb adapter from the computer remove the gps module and install the xbee module
read the module and change that address to something that is not zero. and change the baud to 9600. repete for other module.

13. insert xbee module in to simple board, connect gps module, connect battery

14. check leds on simple board once per sec flash tx

15. check led rx/usb board once per sec rv

16 open mini gps and it should work.

this will give you a gps telemetry module less then the size of a nine vollt battery that will run for a couple of hours offf a nine volt for about 200.00$

notes.

orientation is not a problem with the ls20033 vertical or horizontal it still maintians lock interferences from the xbee does not seem to be a problem with tracking. might be a problem with r/c autopilots however.

nine volts don't have the power to the unit i would suggest either high outputs or 3.7 volt lipos.

rick
 

troj

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Pictures?

I'd be curious to see how this all lays out.

Also, what frequencies is it transmitting on?

-Kevin
 

sylvie369

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XBee are generally 2.4GHz, though there are some newer 900MHz units that have considerably longer range. I flew this version yesterday:

http://www.sparkfun.com/commerce/product_info.php?products_id=8742

to 1600 feet (4" rocket, AT I245), using the same model (with that little wire antenna) on my ground station, and had good data through the entire flight, right down to the ground. I wasn't using GPS, though, just sending altitude data taken from the Perfectflite MAWD altimeter. They're really nice units, and can send the MAWD data with nothing but power, ground, and one serial transmit line connection (the blue wire from the MAWD data download cable goes to the TX line of the XBee, and of course you need a common ground between the brown wire on the download cable and the XBee ground connection). It was really a kick watching the altitude graphing in Excel in realtime, as the rocket flew.

I haven't yet tested to see if it interferes with the deployment circuits - I used motor deployment. I can test that on the ground pretty easily, though, by just connecting a couple of ematches.

I hadn't though about using it to send GPS data, but it shouldn't be that hard to set it up (of course everything is easy until you actually try it).

P.S. - I fly BigRedBee transmitters as well. Love 'em.
 
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rdmmdr

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i am using the xbee pro xsc rpsma at 900mhz for distance and it allows for the dipole antenna. everything is configured at 9800 baud to get the best range. and 1 hz updates. the perfect flight hack is cool did you do any level change or run the 5 volt ttl straight in to the xbee.
 

sylvie369

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I'm using a Selmaware board, which converts TTL level to the levels the XBee requires. They also let me power it from a 9v battery. I could probably use the same battery for both the MAWD and the XBee, but I put in separate ones.

I assume you mean "9600 baud", right? At 1 Hz update, I don't see any reason to go faster than that anyway, and slower is better when range is the real issue.
 

rdmmdr

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try the ww."droids.it" simple board to save size and all you need is two resistors for the level change i also use the droids usb board on the recieve end since i can use it to test the gps units also using the fixed header without having to plug into the indiviual pins for the xbee.

yes i mean 9600 baud. slip of the fingers.

if you are using your work computer with allen bradley rs links software on it the only way to install the driver is to do a driver change in device manager.. the laptop kept thinking that i had the a/b interface connected and installing the drivers for it. it drove me nuts for about an hour.

pictures will come, but i am waiting for the enclousures and light pipes. let me get it dressed before i have to show it.


project status

gps works range about 8 miles was sitting in my truck with my friend driving down the road.

need to get some g10 for a backplane to attach all of the parts, and some big heat shrink. don,t use black it is colored with carbon. still have not decided on the batteries getting about 2 hrs with the nine volt. i am thinking about a pair of 2400mah aa 3.7 volt lipos. that should help with the power side. and give me about 24 hrs of run time. the one time cost is higher but the long term cost is better. and less heat in the voltage regulators running them at 3.7 volts rather then 9 volts.

one thing nice, if you know what you are doing with the x-ctu program one base unit can be reconfigured to talk to any remote in two seconds. might be nice for a club application.
 

sylvie369

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Quick idle daydream: it would be possible to loft a mesh networked XBee in a tethered balloon a few hundred feet up over the range to dramatically increase the GPS range and give you a good chance of getting a signal even after landing. I did some stuff with a group that flies mesh networked XBees in high altitude balloons a month ago, and we did get the signal from one balloon already on the ground passed through another balloon still in the air.
 

rdmmdr

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how high are you planning to fly. the earths curve is about eight inches per mile so if you hold the receiver at arms length you should be able to see it. with a dipole. but yes if it was in a hole the balloon trick might work and the xbee does support repeater.
 

sylvie369

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how high are you planning to fly. the earths curve is about eight inches per mile so if you hold the receiver at arms length you should be able to see it. with a dipole. but yes if it was in a hole the balloon trick might work and the xbee does support repeater.
Well, that line of sight thing would work if the Earth's surface were smooth, but in fact around here it's pretty well covered with trees and buildings and hills and valleys. Direct line of sight generally is lost in well under a mile. Even in flat farmland in western Ohio the signal from the balloon on the ground was not picked up directly by an antenna on top of a van, but still easily picked up and relayed by a balloon over it at an altitude of about 300 meters.

Of course you might not need a balloon - just fly another rocket with an XBee to connect to the network, going just maybe 1000 or 2000 feet up, and I'd think you'd pick up signals from rockets that had landed anywhere in a pretty wide area around the launch site.
 
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sylvie369

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I did the ground testing with ematches yesterday, with no problems. That's not surprising, as we fly dual deployment with various tracking transmitters all the time, though of course on different frequencies than the XBee.
 

cjl

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Well, that'd line of sight thing would work if the Earth's surface were smooth, but in fact around here it's pretty well covered with trees and buildings and hills and valleys. Direct line of sight generally is lost in well under a mile. Even in flat farmland in western Ohio the signal from the balloon on the ground was not picked up directly by an antenna on top of a van, but still easily picked up and relayed by a balloon over it at an altitude of about 300 meters.

Of course you might not need a balloon - just fly another rocket with an XBee to connect to the network, going just maybe 1000 or 2000 feet up, and I'd think you'd pick up signals from rockets that had landed anywhere in a pretty wide area around the launch site.
The GPS I fly with occasionally just remembers the last known position, and that seems to work pretty well. You don't need to know its current position exactly when you know where it was when it was 100 feet off the ground. Of course, the relay solution works too :)
 

sylvie369

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The GPS I fly with occasionally just remembers the last known position, and that seems to work pretty well. You don't need to know its current position exactly when you know where it was when it was 100 feet off the ground. Of course, the relay solution works too :)
I'm sure that's true when you land in relatively open areas, but I fly at Bong, where you can easily be 50 feet from your rocket and not see it. I agree that "last known position" is very useful, though, and I'd guess it'll get you as close as the kind of position information you get from a regular tracker. (I've never flown GPS, so I'm guessing there).

When we flew balloons about 5 weeks ago, the "last known position" GPS signal from the second balloon to land was good enough to get us within about a quarter mile, but I couldn't really tell which side of a road the balloon had landed on. Fortunately, it was laying out in the middle of a field, visible from the road. But the relayed "from the ground" information from the first balloon to land was enough that I was able to lead us directly to where that balloon had landed. If it had been in the trees and impossible to see from a distance, we'd have still been able to walk right up to where it was.
 

Adrian A

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Quick idle daydream: it would be possible to loft a mesh networked XBee in a tethered balloon a few hundred feet up over the range to dramatically increase the GPS range and give you a good chance of getting a signal even after landing. I did some stuff with a group that flies mesh networked XBees in high altitude balloons a month ago, and we did get the signal from one balloon already on the ground passed through another balloon still in the air.
I think this is a good idea, and could really help mitigate the relatively short range of these devices. If you hook a GPS up to this, and if you lose signal, you go go out to the last known location and send up a "helper" repeater on a tethered balloon.
 

rdmmdr

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complete flight testing with version 1 worked great taped to the shock cords and stuffed in a payload bay.

problems noted :
droids board voltage regulator drops out at 4.7 this won't do, will switch to spark fun's xbee explorer board. better regulator
nine volts don't like 300 ma draws get hot, swaping to a 1100 ma lipo.
adding an on board charger for the lipo via usb and a power switch.
package size will be .5x1.5x 3.7
 

n5wd

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If you hook a GPS up to this, and if you lose signal, you go go out to the last known location and send up a "helper" repeater on a tethered balloon.
I know y'all are not talking about the Bee/GPS and/or any of the APRS type of GPS solutions, but....

The 2m Bee/GPS is designed to work in a digipeater environment: a digipeater (in this case, the portable digi lofted in a balloon) hears the tracker GPS packets on 144.390MHz and automatically digipeat's them from the higher position. That's pretty much the way all of APRS works (though it obviously can be point-to-point as well).

Just have to add a decode and retransmit routine to a little repeater (and slightly re-invent the wheel), if it's not an APRS-capable system.
 
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