[SOLVED] Wiring RFD900x to 3DR Pixhawk Mini (4-pin telem port)

Hardware Radios
, ,
1

Here is an ultra-naive question, but my background is programming and I am a total electronics dummy.

I am using a 3DR Pixhawk Mini. The telemetry port accepts 4 pins. The SiK radios I have been using have 6 pins. The Mini comes with a cable that is 6-pin to 4-pin, where two of the pins are empty. Specifically, CTS and RTS outputs are just not used.

I have just received this RFD900x pair. The included telemetry cable ends with the typical 6-pin out. So can I simply cut and solder the 4 wires I need and ignore (seal) the ends of the unused wires? I think its an obvious yes, since I am just copying what was done for SiK-to-mini, but I could be overlooking something important.

rfd900x2mini
rfd900x2mini1280×960 169 KB

Thanks!

2

You are correct in that you can just use the main 4 wires but I would most strongly suggest you do not power the radio from the FC.

With 1watt of output power and drawing ~800mA you will be really stretching the capability of the PixMini.
Much better to separately power the radio.

3

i suggest you power the module with a different power source…, and follow the correct pinout

4

Thanks @mboland and @Dave84. I am glad I asked. I have been planning to power with BEC from the beginning. However, I was just assuming that I would still use the cable the way I described above, limiting power to it from ardupilot params. Then power the module with a BEC. What I did not realize is that I should completely remove the power and ground wires when using an alternate source; I am really going from 6 to 2 3 wires!

Thanks again for the help!

5

it’s always suggested power the periphs with an alternate power surce.
Don’t forget that rfd are high performances so provide a good air flow

1 Like
6

Your signal wires require ground.
So it will be Rx-Tx-Gnd for the flight controller and Gnd-Vcc for the power supply.

1 Like
7

Thanks again! I have triple-checked the pinouts and should be ready to make the connection. My only concern is with Gnd for flight controller since it looks like it was removed here and here.

8

Update: got the radio setup and working fine. Took a while since I was still waiting on the BEC and marine connectors. Its for a boat, so I have to run wiring from inside the hull to the radio container on top. My only concern is heat, since it is enclosed in a pelican case. Field trials later this week; got to let the sealant where I cut into the pelican case set.