Er9x transmitter now with MavLink


The er9x transmitter now will display MavLink data on the LCD.

Gerard Valade a DIYdrones member wrote the software and myself who was the principal debugger.

Works at 19200 and 38400 baud. Still have a problem with 57600 baud. Some kind of timing issue yet.

Here is a pic of the arduplane 2.30 MavLink display on the er9x.

There is an Xbee inside the er9x to receive the MaveLink data from the APN2.0 purple board.

We will post the er9x firmware soon.


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  • you need to realize with a plane or copter there could be tons of data to rx and a fair amount to tx.

    alt,vert rate,lat,lon.speed,compass,heading,sonar data,lazer data,ping data,spit data,p i d tuning,way points,battery, current,consumption,hydrometer,rice cooker,bbq temp,rpm of prop and chicken cooker, number of bombs to drop,leaflet propaganda deployment,lolly-pops and tootsie rolls too.water boodle drop,4th of July missals,marbles,bunker busters, and most important...many little nukes.


  • Thank you for responding, I didn't know the Xbee 900 preformed so well.  5k is do-able for my project so I guess I should just go with those and some nicely built Tx Rx antennas.  Would be nice to know how to amplify the crap out of one of these xBee transceivers.


    thank you for explaining this for me, and I think I understand what you have done here which is AMAZING!!  This is how I interpreted it

    The average setup:

    Aircraft manual control -- 9x(2.4ghz) --> EZUHF --> Receiver --> APM2.0 = controlled flight(with other goodies)

    Telemetry -- Laptop --> USB XBeePro 900 --> XBeePro900 arduino shield --> APM2.0 = mission control(MAVlink)


    Everything -- Modified er9x --> XBeePro900 --> XBeePro900 arduino shield --> APM2.0 = Manual flight control as well as some Ardupilot Control(including way-points)

  • we will get it to work at 57kb soon also..


  • The 900mhz Xbee will go 5 km easy.

    Yes, any rf serial link at 38kb will work. Just remember to compile the ardupilot code for 38kb on serial port 3.


  • Here is link to code

    The hook up is easy. the tx/rx ttl lines from the xbee connect to pin 2 (rx) and pin3 (tx) of the er9x atmega.

    remember tx to rx and rx to tx on xbee to er9x.


  • Joseph, as the Earl mentioned, any telemetry link that is capable of serial communication at the correct baud rate will work.  The APC220 modems I use are in the 400mhz band, and theoretically has a range of about 1km.

  • please bare with me and this stupid question but...  If I understand correctly you are receiving telem data from the APM2.0 (via xBee shield) as well as sending telem data i.e. waypoints back to the APM2.0 directly from the receiver (via another xBee link connected to the RC).

    And if that *is* the case then why can't you just by-pass the whole xBee link (bad range) in lue of a long range UHF system ~433Mhz (great range) using the modified 9x RC?  Would it take up a whole channel?  If so that wouldn't be a problem for some builds, especially mine.  I am pretty sure the UHF waveform can handle it, I send upwards of 64k baud on our military UHF radios... same thing right?

    Again if the answer is longer than 3 paragraphs written in "program-speak" then a simple Yes or No will suffice.

    thank you,


  • Very nice ! Motor current along with mAh consumed would be very useful, if space is not available, you may remove the less important parameter.

  • Great stuff

    I have looked at this development before but cannot figure out the wiring of the XBee from people who have done this. Can't find it on the forums either.

  • @Pete Hollands: I'm no expert, but I believe you can get all the 9x information on:
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