I spent a lot of time trying to get a rover to work with F4 flight controllers (FC). I thought it might be helpful to others to summarize some of my learnings:
- Inav rover software for F4 controllers often does not have all the features of Inav. There is also no documentation of what features are not operable.
- I could not get S.port (smartport) to work on Kakute F4 or Omni F4. It is shown in the flight controller documentation for Betaflight, but I could not get it to work.
- The small OLED displays kind of work but the information displayed has no documentation and is often garbled.
- Adding bluetooth via bluetooth modules is supposed to work but I could not get it working on any F4 controller.
- The FC software or the configurator will sometimes change parameters with no warning. The first step in fixing a missing or inoperable GPS or magnetometer is to check the basic settings, the port configuration, and maybe change the setting to "auto" and force the FC to rediscover the sensor and reconfigure it.
- If you want a high level of functionality in your rover and less debugging hassle, upgrade to an F7/H7 FC. My Kakute F7 could do proper telemetry via S.port with no trouble. The Kakute F4 could not.
- Document your wiring
- Which UART is assigned to which function
- How are the GPS, mag, etc wired to the FC
- Establish one ground connection point and attach all sensors, FC, servos, ESC, battery to that one point.
- Don't count on the FC 5V supply to power the steering servo. Use the ESC 5 volt supply.
- Sometimes the FC 5 volt supply relies solely on the battery, so an external 5V from a BEC will not work if it is connected to a 5V pin on the FC.
- Arming is a hassle with Inav independent of FC. I found that it would only work when I flipped the arming switch AND held the left stick down and to the right.
- 10 series GPS work way better than 8 series. My Beitan M8N finds 4 to 5 satellites when partially obscured. My 10 series GPS finds 7 or 8 satellites in the same position.
Hope this helps.
