Mateksys F405-Wing and Raspberry Pi 3 with APSync

Hi, i have been successful hooking up an esp8266 (the adafruit huzzah board) to serial1 on this mateksys flight controller and got connection with mission planner over wifi working.

I’m trying to do the same with APSync but somehow the serial connection between the PI and the FC does not seem to get established.

I wired the PI and the FC as described on the Ardupilot site and used the APSync image from the ardupilot firmware site. The hotspot from the PI is available and I can see the ardupilot web page when joining the AP at 10.0.1.128 but when I check system status the flight board does not show up with any uptime or data. The FC MAVLink count increases steadily. In Mission Planner i checked that Serial 1 is on 57600 baud and on level 2 mavlink protocol. Changing it to 921600 has no effect even after rebooting both FC and PI.

What options do I have to debug this from the PI or from Mission Planner? I assume the default APSync has Serial enabled.

Regards, Marcus from Heidelberg, building a solar-powerd boat that can cruise for days on the neckar river

Edit: Just found doco to explain how to determine UART voltage - ignore this post. (I can’t delete it.)
Hi @marcusbehrens, I hope you have your APSync issue sorted (sorry, I can’t help) and that the solar-powered boat will be ready for the coming summer. I’m new to flight controllers but wish to establish a similar Mavlink communication that you have with PC to ESP8266 then to Mateksys F405. I have the Mavlink firmware flashed to my NodeMCU. I’m afraid I don’t know the UART voltage on the FC. I’ve found something that indicates that Pixhawk, though running at 5v, uses 3.3v for UART. I expect that this would be the same for Mateksys (and see that there is a 3.3v LDO)…but could you confirm the UART voltage? Perhaps I need to interpose a logic level converter between FC and ESP8266?