I'm getting a boat to work with PX4. I started with the traxxas stampede airframe config and so far the basic manual mode is working OK. I have a number of questions and would really appreciate some pointers for where to get started. I'm new to the PX4 so I'm mostly overwhelmed by the sheer quantity of software parts :-).
My HW config is a boat controlled by a pixracer with one PWM output for the ESC and one for the rudder. I do not have a radio link and am using the mavesp8266 Wifi link together with a gamepad/joystick controller connected to QGC. I am very comfortable with long distance wifi links and expect to shift to a LoRa or similar link when I get out of Wifi range (won't be for a while).
Forward/reverse in manual mode: I am using the joystick with "center stick is zero throttle" and "spring loaded throttle smoothing". It looks like this allows forward throttle only. Changing the settings doesn't give me any reverse throttle. It there a config change somewhere that would give me reverse? If not, where do I have to make code changes? Or is this a major undertaking?
Kill button: on the gamepad there are many buttons and I'd like to map one to a kill switch that switches to manual mode and kills the throttle. Is something like that configurable? Require code changes? A bad idea?
Fixed throttle settings: I'd like to map some buttons to fixed throttle or RPM settings, something like 10%, 25%, 50%, 80%, 100%. Or even better would be to use two buttons to go up/down one "notch". Is something like that possible?
Display of motor Amps: I see the battery level in the top bar in QGC and if I click I see the voltage, is there a way to display the current amp consumption?
I realize some of the questions above may be more related to QGC than PX4...