I would like to connect my companion omputer to my FC.
I have been using pixhawk for a while with USB connection to Raspberry.
Now i want to move the raspberry to the speedybee f 405 wing and seems like i can not succes at connecting using USB.
What are the steps to do it? I suspect i missed some parameters…
Connection between FC and Companion computer using USB on the FC side is not recommended.
Please use a serial connection instead.
Oh, ok.
This is more complicated now.
Since i barely know what i am doing, i now need to find the right tx and rx on raspberry and the right rx and tx on the FC.
On the pi you can use the USB connection.
But it is very easy to find serial TX/RX pins on the PI. It is well documented.
On the FC side you should use a (non-USB) RX,TX pin pair. Speedybee F405 wing pins are documented.
Use something like an FTDI cable to connect it. There are cheaper alternatives as well.
The pi natively supports UART, the best way is to just use the native UART. It isn’t that hard, and you can power the pi through that too. I used it and it works out great. Note that if you plan on using a full sized pi (no pi pico or pi zero), you’ll probably need a separate power supply. A USB connection is a bad idea, you should just use UART.
FYI: Pinout chart: https://pinout.xyz/
I did it, it was quite easy. Now i have issue with picam, buti will deal with it later.
What is best way to power raspberry?
I removed the 5+ volt from telemetry cable, because i think it will not be able to power up the raspberry properly.
I will power it using a 5 amp bec from matek using gnd and 5+ gpio pins.
Is there a better connection point to power the raspberry?
Depends on your pi model and your FC max current in telem ports, but yea you probably should just use one of the 5v pads on your FC, that’s probably going to be your best bet.
I wired tx and rx from fc to GPIO
Than i wired 5v and GND from bec to GPIO
At the moment i have no low power issue.
As soon as i have my camera working, i will verify if the voltage is still ok.
Thank you!
Just curious, why is USB not recommended? I can understand that the 5V powerline could create strange power supply effects, but if only D+ / D- is used?
USB has side effects, the FC assumes that it is not flying and that it is on the bench connected via a cable to a GCS.
I used USB for a few flights as FCU<->Companion connection and had no problems so far.
Can you show me where in the code such side effects might occur?
No, I do not know exactly where that is in the code. You’ll have to look yourself.
I have seen behavior that contradicts that when trying to download logs in a moving car, switching to RTL and activating RC failsafe. Airspeed sensor was disconnected as it is placed on the wing and plane was in a box.
I want to do the same thing via UART but how can you still get Telemetry? Because im pluging the Pi to UART4 and then I stop having the appropriate UART port for a telemetry module…
This is what you have
I would add that Ardupilot FC acts as a MAVLink router so if your companion computer uses MAVLink it will be routed to the GCS, including through the built-in telemetry.
What behavior is contradicted?
Triggered by downloading the logs? Or triggered by connecting via USB port?
I do not understand you post. Please clarify
I had issues downloading logs in a moving vehicle with signs that indicated that the plane assumed it was flying (IIRC radio failsafe triggered even though RC never had signal which doesn’t happen when stationary) even though it was only connected to USB and disarmed.
Hummm that is strange indeed.
It makes sense to report it as a bug.