Mavgen.py to translate, but how?

[patrickelectric (Patrick José Pereira)]

@swagsquad

Then i get a lot of random characters as shown in the picture.

You are receiving this random characters because a second process is using the serial port, probably is the companion mavproxy that creates a bridge between /dev/ACM0 to udp:192.168.2.1:14550 for QGC.

@swagsquad

I read that you had to use the mavgen.py to use the data of random characters, but how do I do that?

If you want to get information from the mavlink protocol, you can use the QGC .tlog files, usually they are in Documents/QGroundControl/Telemetry.
An example of how to use the .tlog files to get an accessible information:

mavlogdump.py 2018-01-02\ 22-48-02.tlog --format csv --types ATTITUDE 

For any further questions check the mavproxy and pymavlink gitter channels.