Error Correction - how can i do it
As part of my "Depron Project", i have made a XBee pro RF transmitter and receiver interface.
(it works very well, however my application will test it to its limits i guess......)
I would like the data to be 100% true. (else my 400gramme areoplane will just be a dot on the horizon - if you know what i mean)
My Question :- I have heard of error correction codes and would like to know what is the best way or method to follow ?.
My system is Arduino based ie Atmega328s.
My data string is so :-
EDIT :- 125,25,255,10,55,1,0 (ie 5 channels values 0-255 , plus two digitals at the end).
now i sent the equivalent character down the line ie. instead of
90,89,88,87,86,1,0 i send just ZYXWV10 (reduction of 18 characters (worst case 23 best case 13) to constant 7 characters)
Thanks in advance.........
@ Tue, 2010-09-07 21:56
LMR Xbee brain storm conference is on
As soon as I know when it will take place, I will post a new forum message. Watch this space. In the mean time, get a Skype account (if you can and if you need to). Make friends with Skype contact "lmrhelp".
@ Mon, 2010-09-13 21:10
Please change your channel
The conference call is here.
@ Sat, 2010-09-04 20:23
good idea
I am going on vacation this week. will be back 9/13. I'll be happy to participate anytime after that. google xbee localization
@ Sat, 2010-09-04 12:43
Xbees are surprising us all the time - - -
How about a LMR Xbee brain storm conference?
I'd love to set up a live conference call with everyone interested and/or knowledgeable in the Xbee capabilities. The radio localization has my special interest, but there are many other applications that were never discussed here on the site.
So here is my invitation. Set a date and time for a Skype (voice) conference. Discuss the Xbee for half an hour or more. Make it a special episode of the LMR Videohelp show. That way other interested people can listen (live or later) to the discussion.
David, you are especially invited to participate. You are bringing a lot of new (to us) information and experience in this field.
Who is in?
@ Tue, 2010-09-07 16:55
I would like to attend
I switched TOBI to XBee after reading an article about a 3-Node network with XBees where a remote sent commands to a robot and the robot sent telemetry to a TV. After reading it I decided that TOBI could use the Signal Strength to locate the direction of the the RoBo Remote controller and make a better decision as to which thermal object was holding his remote controller.
@ Sat, 2010-09-04 13:01
As I’m using XBee on my
As I’m using XBee on my latest project I would love to at least listen to what information the panel could bring us. I’m not much of a talker, -more the silent nerd in the corner :-)
@ Sat, 2010-09-04 14:17
Thats why the shoutbox was invented i think
Silent nerds have the biggest impact......."Scene Changers"
Maybe it.s a good idea that before the event we could brainstrom a few ideas\request\directions\applications etc
I would have liked to have posted a few tips\walkthroughs but my replacement XBee is still in transit.
@ Sat, 2010-09-04 01:22
How about sending every
How about sending every command package three times. If the last three is identical, than all is well. If one is off, its either wrong or it from the next transmission and go for the two identical, and so on…
Read a package, compare it with the last two and keep going
@ Fri, 2010-09-03 23:22
xbees have error checking built in.
TheGrue and oddBot are correct, xbee incorporates error checking into its protocol and under normal conditions the user has no need to do anything to deal with error checking. The default, I believe is the long held industry standard of three retries but is one of the many user definable parameters on the series 2 xbees (not sure you can even get the series 1 anymore). If you're moving small amounts of data, you can superimpose your own error checking on top of what the Xbee does but this is often just a wasted effort as error checking protocols have been pretty reliable for several decades now.
The real problem is going to be when the xbee decides that the comm channel is incapable of maintaining comms, in which case you are are still going to have to handle the problem if and when that happens. hint:remember where that last good contact was made and retreat to that location on loss of signal.
The xbee is one of the most reliable and versatile comms system available. If you learn to use it, it can do wonders for your robot. Because you can see the signal strength of messages from nearby nodes, it can be used for localization.
A lot of R/C fliers have used xbee in planes for telemetry. Haven't heard about anyone trying full control tho. guess it's a control thing. people trust their r/c transmitters. like robots model planes can get very expensive and there are few things more heartbreaking than watching a beloved airplane spiral out of control and auger in into the ground. Been there, done that. ouch!
@ Sat, 2010-09-04 00:02
Analoge transmitting
Thanks for the reassuring information.
Yes i am impressed with the speed of them and they are easy to use and setup.
Yes i was thinking about sending back the RX signal strength and the lipo battery voltage/current levels - ie Telemetry - then at least i will have a prewarning that things are approaching "some" limits.
Unfortunately i am grounded as one of my Xbees past away during a normal Power up - i am happy to say the RedBox (hinthint) supplier is sending me a replacement ASAP , it came at a bad time as i was starting to do some range tests of the links before the launching..... Shift happens......
Can you explain what you mean in your text "it can be used for localization" ?