Servers by jDrones

Telemetry with PPM?

(Ruben) #21

I actually setup a Raspberry PI Zero W with the RFD900x connected to it on it’s UART. Load when running mavproxy is around 0.6 while the thing is also doing DNSMASQ and Hostapd.

So, as for cheap options go - it works.

I didn’t do a test flight or so. Waiting for a power supply. I like this setup and it could be a very small package in the end, so easy to mount on a pole.

(Dan Pollock) #22

Seems to me that if you had companion computer on the bot then you could have multiple control data streams on one channel of the rfd900 series radios. Using ppp encapsulated slip packets across one of the channels. Like when you used to connect to the internet with a phone modem. The RFD900x just provides the serial link doesn’t matter what you run over it. DSM control packets are really small so plenty of room left for other things. PPM is not difficult to generate.

(Dan Pollock) #23

Yea they are useful. With pigpio and piscope its easy to set up control signals to go over the RFD900 link. Develop on a pi III and just move the sd card over to the Zero. Haven’t tried gstreamer yet for video. Pity the model with the csi camera interface doesn’t have wifi or bluetooth.

(Ruben) #24

Model with the csi camera interface does not have WiFi?
My pi zero w had a raspicam v2 connected to it!
I can’t try gstreamer soon, but willing to try. Motion software was a bit too heavy for the cpu on the zero

(Andrew W Morgan) #25

Allegedly RFD is coming out with a JR module bay insert containing something like a PiZero-w and a 900x. Seems to me almost like the perfect solution for use with something like a FrSky Q-X7.

It probably won’t make injecting RTK correction data any easier but I like that the radio link to the aircraft is actually powered by the r/c radio.

(Samuel Salomão) #26

Hello, I need some help to understand how to make this PPM passthrough work.

@JeffBloggs Would you have some more info on how to configure the software and connect the hardware? We are using a pair of RFD900x radios. The local radio, the one connected to the computer, has the checkbox GPI1_RCIN (Pin15 input) enabled. The remote radio on the drone has the checkbox GPI1_RCOUT (Pin15 output) enabled.

The local radio has the Pin15 (input) connected to a FrSky XSR receiver S.Bus output. And the remote radio has the Pin15 (output) connected to the Cube RCIN signal terminal. Please, look at the pictures. Is there anything else I am missing?

(Evan Williams) #27

Is your intention to use S.Bus or PPM?

For PPM I believe you would use the CPPM pin of the X4RS - S.Bus may work, but I’ve not seen anyone try it.

(Samuel Salomão) #28

@Evan110011 Thanks for your insight!

When I was using the XSR receiver onboard, I was using the S.Bus. And it was working correctly. But, connecting the S.Bus wire to the Pin15 on the RFD does not work. So I tried connecting the CPPM wire and Voilá!! Now I can control my drone via RFD passthrough.

Very cool!! Thanks!!

1 Like
(Travis Bridges) #29

This post had the most discussion of PPM on 900x. I had a similar question in the same vein.

Right now, I have my modem set up this:

Would it be possible to instead set it up like:

And get telemetry scripts running on the taranis?

1 Like
(Jace McCown) #30

Revival: @thatsnailguy did you ever figure this last question out? I’d be interested in a similar setup

(Travis Bridges) #31

Yes, I did! Sorry to not report my setup. Unfortunately I am on vacation until next week, will update with my specifics then.

(Jace McCown) #32

I anxiously await your reply!

Jace McCown

(Travis Bridges) #33

Check it out at this post. To get it working I needed to use OPs teensy code.

(Jace McCown) #34

I’m going to revive this with a question on the same topic. Currently using rfd900x to pass telemetry only and frsky rx8r for RC. I’d like to get some redundancy and range with the RC by piping PPM through the rfd900x.

Heres the idea: continue to use frsky rx8r onboard the aircraft with the Rc bound to it. But also bind to an xsr at the groundstation and output its cppm over the rfd900x (as seen on @samucs post). On the airplane, pull off the cppm and convert it back to sbus and feed it into the redundancy port on the rx8r (with something like this).

any chance this will work? are there issues here with 3.3v vs 5v logic levels (and how do you solve that?)

(Charles C Spencer Iii) #35

Anyone know if the ppm will pass directly to the computer giving the ppm choices plus the 14 telemetry choices together 16+14 +30. It would be nice to have that. Otherwise I see no use for it. I use a throttle and joystick from a laptop…