I flew quite a lot with pixhawk system with various setups and know about connecting devices like sonar, optical sensor or lidar.
I felt confident configuring pixhawk system until recently I have an order to setup a pixhawk drone for autonomous spraying mission. Set it up for spraying was quite easy however, detecting empty of the tank turned out to be a heck of a work.
One solution I found was to install a small level detector with hall effect sensor in it and connect the output to one of the ADC channels in pixhawk.
After all, I could not find any corresponding setup in the mission planner. There is no way to detect the sensor input other than sonar range finder's analog output and once utilize this input, the drone become crazy at altitude holding.
So my question now is how to enable other ADC channels and detect something other than sonar.