Set manually PWM output on Pixracer and in SITL

Hi everyone, I’m a newbie on PX4 and I’m trying to understand some basic stuff.

I would like to do a simple operation: set manually the PWM value on the 5th pin of the Pixracer, but I’m clearly doing something wrong.
I discovered that inside the topic “actuator_outputs” there are the PWM values for all the 6 channels, therefore I created a simple module (following “Writing your first application”) which publishes the constant value I want on the 5th value of the array “output”. It correctly writes the value I want on that specific point, but at the same time all the other outputs are set to 0, and it locks the drone in the simulation (after launching “commander takeoff” I run the module and the drone locks in the middle of the air without moving propellers).

Right now I don’t have the hardware, therefore I’m using SITL with gazebo (px4_sitl_default). Do you have any suggestion? My idea is to write a module that only sets the value of that specific pin, I don’t want to interfere with the other values.

Thank you for reading

I’ve just figured out a possible indirect solution. If I publish a number between -1 and 1 on the 6th value (control[5]) of the topic actuator_controls_3 (this control group) I can actually change the 5th PWM output exploiting the standard mixer file, without interfering with the others.

What I’m wondering is whether it is the best solution or not.