Replies to This Discussion

DeveloperPermalink Reply by R_Lefebvre on January 28, 2012 at 1:29pm

Is that error +/-2m or +/- 2cm?  I thought the units was cm, not meter.

I've seen one guy had success putting a toroid on the ground wire of the Xbee.

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Permalink Reply by James Roney on January 28, 2012 at 1:31pm

+- 2m, I did try a toriod, however without much success.

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Permalink Reply by Fatih Gokce on January 29, 2012 at 4:09am

I suggest you to read this thread if you have not yet: http://www.diydrones.com/forum/topics/arducopter-2-0-50?commentId=7...

But in our case twisting 5V&GND worked better as indicated in the comment below taken from upper link:

"This was very useful for me! I tried it and the result was pretty good!! I did another experiment and for me it worked even better, Just twist the ground and the +5v wire and the problem is also solved. when the twisted wire is longer result is better, i have 15cm length twisted."

I suggest you also to take the power for telemetry xbee from servo rail instead of four pin telemetry port. 

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Permalink Reply by James Roney on January 29, 2012 at 11:13pm

Hi,

 

I will try the variations as described and see how I do.  I will report back with my results a little later on in the week.

 

Regards,

James

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Permalink Reply by Carlos Moreira on January 30, 2012 at 5:15am

Same problem here...

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Permalink Reply by James Roney on January 30, 2012 at 9:34am

Right,

 

I have tested all methods as described.  Twisting longer +5 and gnd.  Putting the gnd wire through a ferrite ring.  Putting the ground wire and 5v through a ferrite ring.   Putting all wires through the ferrite ring.  Twisting pairs and then putting through a ferrite ring.  Using the above methods I was able to reduce the the sway to around 1m.  However removing all the additions and going back to just holding the tip of the antenae, the sway was only around 30cm total.

 

Has anybody else got any further ideas on how to get this resolved.  Flying with out telemetry sucks and it works wonders for on the spot tuning...

 

Regards,

James

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Permalink Reply by Olivier on January 30, 2012 at 4:21pm

Hi James,

I've got the same problem. I think it's due to the wire antenna. I've done a test, by swapping xbee boards between pc and copter it reduce the baro noise. The wire antenna has no "ground", but the 900 MHz RP-SMA antenna is quite big.

You can try to change your cable (between apm and xbee) by a longuer one, twist ground and 5v cable and fix the xbee as far as you can from the APM. Try to move XBEE in different place, you will notice some changes.

In my case, I've never found a solution with 900 MHz, so I've change my XBEE pair by a 2.4GHz PRO S1 pair.
Now It works fine.

 

Regards.

 

olivier

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Permalink Reply by James Roney on January 30, 2012 at 10:12pm

Hi Olivier,

 

Where did you purchase the 2.4 Ghz versions?  How is the range compared to the 900Mhz system?

 

Regards,

James

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Permalink Reply by Olivier on January 31, 2012 at 1:35am

I've purchase 2.4 Ghz here: http://www.buildyourowndrone.co.uk/

Nice contact and great services from Martin.
About range due to winter weather I've not done long range test.

I've only done test between my home and my garage, it works nice thru the large wall (approx 40m)

For the moment I don't need very long range, It's just need it to tune my quad on the field.

For Info I've a futaba 2.4Ghz system, from the first test I've made (at short range), I've no problem.

When weather will be better, I will do some external tests.

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Permalink Reply by James Roney on February 2, 2012 at 12:17pm

Problem resolved:

 

I detuned the antennae on the copter side by trimming the wire down by around 15mm and then coiling the remaining antennae around a pencil.  This has 100% resolved the noise.   I realise that making the antennae shorter could risk the modem however there seems to be no problems yet.  I am also sure that I have drastically reduced the range, however at the distances I am currently flying(75m - 100m) I have had no degredation is performance as yet.

 

When I upgrade to APM2, I will then purchase the 2,4Ghz Xbee.  I will then add length back to the antennae and use APM1 for an automated ground vehicle.  Something extra to play with when flying is not possible.

Thank you for your assistance.

 

Regards,

James

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Permalink Reply by Fatih Gokce on February 7, 2012 at 4:58pm

Another solution is to give the power to Xtream bee board carrying 900MHz module from a separate BEC. We have tested this method in indoor auto land using only baro. It was a success with a small bounce! (To be able to test indoor auto land, we first waited for GPS lock by putting the copter near a window, after that we did a manual takeoff and then an auto land.). Although current solution seems to work enough, we also plan to add an RC filter (probably adjusted to 900 MHz) to the power input of Xtream bee board.

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