3D Robotics

3689600537?profile=originalI just got a Quanum Nova, which is a fantastic APM-powered copter that in many way outperforms the DJI Phantom for less than $300.  Although it's capable of full autonomy, just like any other ArduCopter, the one thing it's missing for easy field mission planning and DroidPlanner compatibility is telemetry. 

In this great tutorial, Jean-Louis Naudin shows how to add that:

Here an explanation for connecting the real time telemetry to the CX-20 or to the Quanum Nova

The telemetry port is located on the I/O board of the APM (the second board at the bottom and pluged to the main CPU board) where all the I/O plug are connected. The telemetry port is fully compatible with all the telemetry transmitter (3DR and all the compatible boards) and also with the Bluetooth boards commonly used with the APM boards.

alt text

Below the pinout which shows the telemetry port I/O (back to the I/O board).

Note from the comments: depending on which radio you're using, you may have to reverse the TX and RX lines. Dmitry in the comments reports: "You must connect RX from the radio to TX on the APM! And vice versa for Radio TX. So I've changed green and yellow wires and it works!"

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sold 4 cables on the telemetry ports alt textthen protect the connections with hot glue alt text

Check the functioning alt text

The 4 pins telemetry plug is installed on the back of the fuselage alt text

Check the connection (at 57600 baud) with the mission planner or the Droid Planner 2 alt textalt text

Then, you may enjoy to use the telemetry... alt text

NEXT CHAPTER: Full autonomous mission with the Cheerson CX 20


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  • Just was pointed to this new summary that seems pretty definitive. Thanks!


  • Yeah. A few posts back I gave an rc groups link to someone with the e solution. some of the novas incLudington mine don't give Amy TX or rx off the pads in the tutorial. You gotta do some tricky soldering
  • Correcting, APM firmware is at 3.1.5 -- 2.0.14 is MP version. Sorry about that, Chief!

  • Hi. If I'm barking up the wrong tree here, my apologies in advance. I have a Quanum Nova that I'm trying to get working with 3DR type radios. Here's the situation so far:

    1) APM firmware is at 2.0.14
    2) 3DR radios are at latest stable version
    3) 3DR radios talk to firmware program fine (both ground unit, and air unit connected via a USB/serial converter. Both radios connect to each other fine.
    4) Nova data appears fine when connected to Mission Planner via USB.
    5) No luck getting data out from Nova via radio using cable wired to APM contact pads.
    6) Air radio powers up correctly attached to the Nova (5.25v VCC).
    7) Wiring attached to Nova contact pads shows continuity and apparently no shorts.
    8) TX data line (pad next to VCC) is at 5.25 volts, no data visible (testing with battery connected, USB disconnected). No red blinking from air radio.

    Any ideas? Thanks very much!

  • @Manuel, I have read of a guy with 3.1.5 & a working telemetry port too here, but then he says it only works without USB plugged in so I know he means the RX/TX resistor spot and not the telemetry port that we are trying to get working. I tried to explain it to him here. I would bet that if you used MP to flash 3.1.2 or 3.1.5 over top of your stock 3.1.2 without any other changes, your telemetry port would quit.

    What we need is someone with a stock firmware, to get a complete hex dump using the ISCP header shown here.

    RC Groups - View Single Post - CX-20 Cheerson Auto Pathfinder
    RC Groups - the most active Radio Control model community: electric and fuel rc airplanes,rc helis,rc boats and rc cars. Features discussion forums,…
  • Thanks for that information Manuel. What I noticed first time I connected to the APM planner was several data packages that I never had seen before as the progress bar was coming to the end. These were gone, together with the telemetry, after upgrading to AC3.1.5 and back to 3.1.2. Also, the possibility to enter compass calibration was gone.

  • There seems to be some controversy regarding telemetry and Nova/CX-20 firmware...

    I'm on stock 3.1.2 and have  telemetry on telemetry port working

    Another guy at RCG is on 3.1.5 and have telemetry working on telemetry port

    And then, there are some that updated to 3.1.5 and telemetry isnt not working on telemetry port (but it's working on RX/TX resistor pins)

    So Nova/CX-20 3.1.2fw cant be a custom firmware...

    There must be something that's missing to us... why is it working for some / not working for others

  • I never got hold of the original Nova/CX20 FW, only AC3.1.2. Thus my telemetry link, like yours, is still not working. I hope someone find a solution for this as we really should fly with AC3.1.5 and link ;) 

  • PF, can you share where you found the CX-20's stock firmware. I'm in the same situation as you were/are. Long story short, had to flash firmware via MP and now telemetry is not working.
  • Avi, I would try swapping the Tx, Rx, or use this post.


    I had to solder Tx and Rx to those resistors to get mine to work. Apparently there are some boards that are built different.

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