Tx transmit 4 channels - Navio mix and control 8 channels?

Navio / Edge Hardware
1

Hi,

I’m looking to control a large number of channels using the Navio board, as many as it can really.

As an example, say on the UAV I have 8 channels (4 flight surfaces and 4 motors). I’d like each motor and surface to have its own receiver output rather than using y harnesses, but I’d also like to only transmit 4 channels. So lets say there’s no Navio and it’s a regular RC plane - I could plug everything in to the receiver (all 8 channels) and mix on my controller so everything is just controlled using the sticks. (I’m transmitting 8 channels in this scenario).

Is it possible for Navio to do this mixing and output 8 channels, while only transmitting 4 channels from the transmitter? 4 channels from the transmitter to the receiver, 4 channels into the navio, it does the mixing and outputs 8.

I may not have explained it as clearly as I should have so please let me know I’m not getting my point across.

Cheers,
Andy

2

so what you want to build/drive is a four engine plane with 4servos for rudders?

3

not necessarily four rudders but four control surfaces (2x ailerons, 1x elevator, 1x rudder).

I’d like to do the mixing on the navio board rather than on the transmitter, thereby only transmitting 4 channels but the navio outputting 8 signals

4

(rudder was just a bad translation from german on my side - of course i meant control surfaces)
theoretically that would be possible on Navio2 - but i could’nt really find out if ardupilot supports “4 motors output” on a plane; (Archived:Channel Output Functions — Plane documentation) it seems natively it doesn’t;
if you can split the throttle signal to all 4 ESCs - then transmitting 4 channels is no problem for flying; (but i’m not sure if a simple Y-Splitter can transmit one PWM to 4 ESC’s - but I never tried that!)

5

The latest version of Arduplane supports a second throttle channel. If you look into the full parameter list under rcX_function you can tell every pwm output which function it should execute. Enter 70 for second throttle on rc5-14 and connect two of your ESCs to that output. The documentation is still a little thin on this, so I do not know if you really get any benefits from the second throttle channel, like differential throttle or anything.
I left my Twinstar the way it was, using just one throttle and a y-cable.
It should be no problem, to connect 4 ESCs with y-cables. Hobbyking delivers their 4in1 ESCs with a 1to4 hub to calibrate all 4 ESCs at once, for example.

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