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  1. Imre says:


    In 2016 I started my ULRS sponge boards project, but stopped due to new babys born “issue”.
    Now I want to continue to use them and develop a best solution to fly more distances.
    So, is this project from your side a live project? Where is a fresh information and new fw releases?

  2. Charles says:

    At present with orangerx hardware ultimate lrs firmware is the best combination,you have done a pristine work here with ulrs system and excellent documentation.

    I’ve a S500 quad, currently using frsky djt module with 9x radio and opentx. I’ve been searching for a uhf system and found ultimate lrs is the best at the moment if mavlink is the priority. Other uhf systems are so expensive I can’t justify spending that much.

    I’m going to order the new hobbyking 1w rx and the regular 1w tx from hobbyking, beacause at this time I can’t diy a new mini ulrs module and the new orange tx/rx is quiet affordable. I know you don’t have any plans for new features to be added, but I would request you to atleast add support for the new rx which requires minor hardware mods and I’m not sure if remapping of rssi and cppm pin is required. Also about the failsafe system, right now I use no signal method with frsky/pixhawk and its very robust, so atleast provide support for the new orangerx rx.

    Thanks & Regards

    • admin says:

      Thanks Charles, I’m happy that you appreciate this system 🙂 I’ll consider supporting the new OrangeRX module, but can’t promise a date for this.

  3. Pierpaolo says:

    Hello Gents
    I’m a quite experienced RC hobbyst and in the last years I’m exploring FPV.
    Following your project I purchased 2 orange RX 1W modules in order to have a stronger RC link (with telemetry too) with my planes/quad.
    I’m currently using naze32 chinese clones with good results (INAV), but all the post are related to APM.
    As soon as my new modules will arrive I plan to use with Naze32 fligh controller and EZ-GUI GCS, serial link should work the same of APM so at the moment I can’t see difficulties.
    Can you advise me if I’m doing something wrong?

    • admin says:

      There are some Naze32 users, the best is to join the rcgroups forum here :

      • Pierpaolo says:

        Hi, a quick summary of my experiences with naze32.
        I succeded to couple ULRS (beta 2.35a) toghether with naze32 (Inav1.7.1) throug PPM. You have to set receiver to 8

        channels only – not yet tested more than 8 ch
        I’m using as a TX an Orange 1W for Jr (for my Turnigy/Taranis) and a wolfbox 100mW or a Orange 100mW (futaba type)

        as RX. Both Rx modules works as expected in the same way.
        I succeded in receiving telemetry data from my remote naze32.
        Configuration I tested is:
        FTDI cable connected to the TX module and the PC running GCS for Naze32
        RX module connected in PPM to Naze32 and RX/TX only (be careful to 5V Vcc on Naze serial port) connected to a

        softserial port 1 running at 19200.
        I can see my windows10 pc GCS showing telemetry as soon as I move the Fligh Controller.

        I’m testing bluethoot connection between TX serial and GCS (for PC or Android) but I ‘ve found a possible trouble related to 3.3V as Vcc on serial port of the TX orange. This voltage is out of spec for my Bluethoot module (HC-06) that is rated from 3,6 to 7volts.Pratically it works but as you move the GCS few centi(metres) away from TX module it starts loosing packets. I plan to solve with a dedicated 5V supply to the Bluethoot module inside the Orange TX module.

        I can upload a small video showing my results


  4. ggwarrier says:

    Thank you for your wonderful work.
    My understanding is that the OrangeRX modules can be used for two way telemetry or R/C. I have few questions (I apologize for my ignorance on the subject)

    1. When changing firmware does ULRS automatically set the module as Tx or Rx?
    2. How can I switch the air module in Tx or Rx mode remotely for two way or can the RFM23BP be used in duplex mode automatically?
    3. I also have a Wolfbox 1watt module. Can OrangeRX and Wolfbox both at 433 MHz be used simultaneously?
    4. Have you released version 2 and how can I obtain it (I understand it is not free which is quite ok considering all the excellent work you put into this)?


  5. Ivan says:

    Hello! Thanks for your work!! Tell me, is it possible to work with your device RFM23BP 868 MHz modules?

  6. mifan says:

    Hi Benoit,
    I am interested on Ultimate LRS firmware, would be possible to use it on OrangeRX only for telemetry without PPM signal?
    Thank you for answer.

  7. James says:


    Is this a good antenna for aircraft and groundstation?



  8. Robin Lobelle says:


    Thank you for your fantastic project.
    I currently have your firmware running on 2 orange 1w tx’s. One is conected to my apm 2.6 board, the other to my taranis X9.

    The link between the apm and my laptop is ok, but the copter won’t arm. I get “prearm: check board voltage”.

    I also noticed that the battery reading has droped +-1V in mission planner after attaching the orange tx to the copter.

    Removing it gives me the correct voltage again.

    Is there any solution to this problem ? I read about changing the config.h file, but have no idea how to do that.

    Thanks !

    Robin Lobelle

    • admin says:

      Hi, it’s preferable to power the ULRS directly from the battery rather than from the APM. The 1W modules have a switching regulator that can accept up to 36V battery voltage !

  9. nico38 says:

    Hi Benoît,

    This is very interesting project ! I have actually a pixhawk with 100 mw orangerx module with openlrsng.

    Before I use your project on my orangerx, i would like to know if channel 1 in config tools of ultimate lrs V2.0 correspond to RSSI channel ?

    I explain why i have this question :
    In PPM configuration, I would like to redirect RSSI signal on channel 8 beacause the minimosd extra Version R800 have an option to receive on PPM channel 8 RSSI signal (who in configured in config tool without any other connection).
    Then I have not the RSSI signal in pixhawk but directly on OSD screen (refer to this screenshot : .

    Thanks in advance and many thanks for your works !


  10. Rudolphe says:

    Hello dear,
    The Wolf box work with a turnigy 9x? Impossible to find an orangerx kit available…..
    Thanks a lot for your help

    • admin says:

      The alternatives to OrangeRX are presented here : I can’t confirm if the Wolfbox will physically plug in the Turnigy 9x but it will work if the power + PPM signal are connected to the right pins.

    • ondrej says:

      Yes, it works perfectly together!

  11. Johannes says:

    Hi Benoît,
    just found your site and this project looks really good.
    Think i will try it on my next Pixhawk Build.

    I found the description for the Ultimate LRS Mini.
    Seems to be a nice and cheap alternative to the Orange Modules.
    Do you have some more information on that?
    Is it already supported in your software?

    Greetings from Trier


    • admin says:

      Hi Johannes,

      All the information is on the ULRS mini page, it will be supported this week with the release of the beta 2.24

      The schematic is very simple so it’s even possible to DIY it, or make it on a small breadboard. I’ll propose a PCB probably in June 2016 (just the PCB).

  12. leif says:

    Hi, the page “Ultimate LRS Mini” has no comment button so I ask here about the “Ultimate LRS Mini”:

    a) How is the RFM23BP powered? Has the 5V line to be connected to some 5V source or does the module get power from the regulator of the arduino? What voltage should be on the RAW input?

    b) I’m no arduino expert but is there a reason using a 150nF capacitor? Other designs use 100nF?

    c) Is the mini design ready for prime time? I would have used the orangeRX but they are on backorder for weeks…

    d) is there any chance that you release the source? Using an arduino gives plenty of custom options that scream for the source 🙂



    • admin says:

      You’re right, I’ve now allowed comments on that page.

      a) Maybe your comment was anterior to the latest version of the schematic, but the RFM23BP is powered by a LM317 adjustable regulator. This allows to adjust precisely the output RF power. Notice that all the “V+” pins are to be connected together, and to the ‘RAW’ input, which means the battery.
      b) Good catch ! The value is not critical, and I should even remove completely this capacitor, as the Arduino mini board already has the 100nF capacitor.
      c) You can make your DIY board based on the schematic, it will work with the beta 2.24 that will be released this week.
      d) The version 1.06 is released under GPL and you can have find a link to the source code on this site. The version 2.X is actually a different project made from scratch and which is closed source but offers more features. It will soon become a paying version so that I can allow more time for the development of advanced features.

  13. Enea Ermini says:

    new to the hobby I was wondering if I could use your system with the cheap Hobbyking OrangeRx T-SIX 2.4GHz DSM2 radio controller … Is possible to disable the inboard TX and enable the openlrs instead? If so, how? I have searched on mighty google but find no info about it !!!

    Many thanks in advance

  14. bjames03 says:

    Thank you, this looks great! Quick question, I was considering using this with Mavlink OSD but Mavlink seems to need SERIAL1_BAUD set at 57600 while UltimateLRS uses SERIAL1_BAUD at 19200.
    Is this a problem anyone has run into?
    Thanks again, cant wait to get this installed and running.

    • csomyy says:

      You can set 19200 baud on the APM or pixhawk using USB cable. USB will use 115200 anyway.

    • admin says:

      If Mavlink OSD requires 57600 bauds it won’t work. See if you can recompile it for another baudrate ?

      • Bill James says:

        Thanks for quick reply guys. One more quick question, will this work the same running ArduCopter (Quad) on the APM instead of ArduPlane?

        • admin says:

          You can run anything, it acts as a serial link. It works with APM:Plane, APM:Copter, APM:Rover, and some users use it just as a long range radio modem.

      • csomyy says:

        YEP! I’m in this too.
        I will compile an osd vwerion for 19200 baud.

      • Bill James says:

        Just want to let you know I recompiled MinimumOSD extra at 19200 and it appears to run fine with your code.Thanks again for all your work. How do I go about buying you a cold beer?

  15. Nick says:

    Can two or more ULRS systems be used in the same location? How does that work without binding? I just want to make sure it is safe to fly. Thanks.

  16. Flanker says:

    Thank you for the awesome work. Any news on the GUI? I love ULRS for my quad, but I don’t have apm on some of my planes and I’d really love to have PWM output. Cheers.

  17. Flanker says:

    Hey there, just wanted to let you know that updater program can no longer reach the firmwares(404 error) Also I got a question. I got lots of spare 100mw orangerx modules. I want to use them on my planes.(with 1W tx on the back of taranis)

    I know telemetry range would be limited by 100mw, but I was wondering If i could somehow disable telemetry function on UltimateLRS, and just use them one way. Theoretically then the range would be limited only by 1W TX module.

    I don’t want to flash OpenLRSng to my TX, since UltimateLRS is a must have for my quad.

    • admin says:

      Thanks, actually there’s one combination that’s not possible, it’s to have a 100mW board as TX. You can use it as RX but not as TX, or you’ll get a 404 message (that will be changed in the next release).

  18. Jean Joubert says:

    Absolutely Fantastic!, It just works. Works well with Opentx Mavlink Display on 9XR. Anxiously awaiting DTFUHF Support Thank you!!!

    • Ondrej says:

      Dear Jean! Great to see your message!!!!!!!

      Please, which changes did you make on the Wolfbox TX PCB to use telemetry on TX display? Wher should be soldered links for TXd and RXd ? Is it necessary to cut any links? Thanks a lot for answer! Ondrej

  19. Lazybee says:


    Thanks for Ultimate LRS!!!
    I love the simplicity of your projects !!
    Ultimate LRS is an ingenious little masterpiece!

    And now ….. Additional channels? I salute!!!!

    How far have you come with the code …?
    I hope it is not long to wait ….. 😉

    I use Ultimate LRS with cleanflight on cc3d and naze32 cards
    and it works absolutely perfect!

    Additional channels = BRILLIANT!

    Regards from Norway

    • admin says:

      Thanks for your comment, next version with additional channels and lot of mavlink new stuff is coming soon

  20. Mr-Fiero says:

    Wow, I knew about your project using OpenLRS radios for some time but never tried it till now. It works so well! I have never seen reliable telemetry over OpenLRS before.

    Now I am using Harakiri firmware via 32bit processor, sending Mavlink over OpenLRS and then Bluetooth to my phone from my RC-TX using droidplanner2 and EVERYTHING just works. No glitches, drops, or anything.

    I took the time to write you because I wanted to say thank you very much for sharing your work. I really appreciate it and am really going to enjoy using your firmware this summer. I am really impressed how reliable everything is, and its very fast performing.

    My only wish, is that I could set no channel hop, and use a dedicated frequency as I am a licensed radio operator, and I like to tune my antenna’s to only one frequency to maximize my range. Is this possible with your firmware? I did read you might consider a gui to customize options and I would be very interested in testing once you have done that.

    Any-ways, thanks again, and take care…..

    • admin says:

      Thanks for your comment, I’m currently working on the GUI and having the choice of parameters such as hopping channels (or no hopping at all) will be included.

  21. julien says:

    bonjour, tout d’abord félicitation pour LRS !
    Je l’utilise depuis quelques temps avec 2 modules 1w hobbyking dopé en 5v et avec le bluetooth sur le tx et cela fonctionne vraiment tres bien.
    Cepandant j’utilise aussi des modules 100mw hobbyking pour mes autres models et de ce que j’ai pu mesurer, je n’ai que le rrsi en 1 et le ppm en 4.
    Il y a t’il un moyen de pouvoir utiliser des sorties servos ou un autre firmware compatible avec votre 1w hobbyking tx 1.06 stable.
    Merci et bonne continuation.

    Hello, first of all congratulations for LRS!
    I use it for some time with 2 1w HobbyKing modules 5v and doped with bluetooth on tx and it really works very well.
    Cepandant I also use 100mw HobbyKing modules for my other models and what I was able to, I have the RRSI in 1 and 4 ppm.
    There is there a way to be able to use servo outputs or other firmware compatible with your tx 1.06 1w HobbyKing stable.
    Thank you and good luck.

    • admin says:

      Hi, this is a feature that’s planned for a future release

    • moti says:

      I loaded the last FW now ….no bindidbg, Tx module lite red blue flash rapidly and same the red Rx lite.
      any suggestion….thanks

      • admin says:

        It’s perfectly normal : one LED blinks when packets are sent, and the other one is blinking when packets are received. So all LED must be blinking when everything works fine. There’s no special binding procedure, except that the modules must be configured to the same bindcode and channels.

  22. Mike Christiansen says:


    Thank you for your fantastic firmware Ulrs! Very easy to set up, a nice efficient system. I currently have your firmware running between a orange 1w tx and a hawkeye 9ch 500mw systems.

    Im not sure if you have had any interest from other users or not, but I would be willing to make a donation towords firmware that will work with the Atmega32u4 based DTF UHF hawkeye delux tx.

    Thanks again,

    Mike Chrisitansen.

    • admin says:

      Hi, I’m working on a version for the DTF UHF Deluxe TX, my paypal address is

      Thanks !

    • Cyril says:


      Thanks you for all the work you did on this amazing stuff.
      With a friend we soldered a couple of DIY ULRS board and we quickly had a mavlink connection between our ground station and our plane (pixhawk derivative apm).

      We try then to send ppm through the ULRS but nothing happened whatever we try.
      Do we have to connect our Radio Command PPM output (it’s an old futaba) to the PPM pin on the TX ULRS module ?
      Is there something we miss ? We try every configuration and different ppm signal on PPM input. So we don’t know what to do now.

      We notice that when we connect the 5V ppm signal from the futaba into the PPM ULRS tx module the signal drop to around 1V.

      I hope you will be able to point to us what we did wrong.

      Best regards,
      Cyril & Mic

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