Adding New Parameters to v1.15.4

PX4 Autopilot
1

Hi
I know I’ve seen posts about this before, and I feel like I’ve tried everything. I’m attempting to add a driver to v1.15.4 for a sensor I’m trying to use. I’ve been able to validate that it works by starting it via the nsh in QGC and am reading in data properly. The final step I have for integration is creating 3 parameters that I can set via QGC to enable, set the polling rate, and a mode. However, I can’t seem to get the parameters to show up. Below is the header that I created:

class MAX6675 :
	public device::SPI,  // ★ NEW: Integrates PX4 SPI device base class
	public I2CSPIDriver<MAX6675>,  // ★ NEW: Enables PX4 module autostart
	public ModuleParams
{
public:
	MAX6675(const I2CSPIDriverConfig &config); 
	~MAX6675() override;

	// Initialization (sets up SPI and schedules periodic Run())
	int init() override;

	// Main polling function (called on scheduled interval)
	void RunImpl();
	static int main(int argc, char *argv[]);
        static void print_usage();
protected:
	virtual int probe();

private:

	// Parameters
	DEFINE_PARAMETERS(
		(ParamInt<px4::params::MAX6675_POLL_MS>) _param_poll_ms,
		(ParamBool<px4::params::MAX6675_ENABLE>) _param_enable,
		(ParamBool<px4::params::MAX6675_FAHREN>) _param_fahren
	);

My module.yaml file:

module_name: MAX6675

parameters:
  - group: Sensors
    definitions:
      MAX6675_POLL_MS:
        description:
          short: Poll interval for MAX6675
          long: Sets how often the driver polls the MAX6675 SPI thermocouple sensor.

        type: int32
        unit: ms
        min: 10
        max: 1000
        default: 100
        reboot_required: false

      MAX6675_ENABLE:
        description:
          short: Enable MAX6675 thermocouple
          long: Enables Max6675 on external SPI bus

        type: boolean
        default: false
        reboot_required: true

      MAX6675_FAHREN:
        description:
          short: Fahrenheit output flag
          long: If true, the driver will convert temperature to Fahrenheit. Otherwise, output is in Celsius.

        type: boolean
        default: false
        reboot_required: false

And my CMakeLists.txt:

if(CONFIG_DRIVERS_THERMOCOUPLE_MAX6675)

px4_add_module(
	MODULE drivers__thermocouple__max6675
	MAIN max6675
	SRCS
		max6675.cpp
		max6675.hpp
	MODULE_CONFIG
		module.yaml
	DEPENDS
		px4_platform
)


endif()

I’ve seen this post: Custom parameters' description not showing in QGC - #4 by whiss
And have followed the steps in that. However, when I run that command I see the build directory populate for px4_sitl_default. I’ve still compiled for my board (cubepilot_cubeorange) and then flashed with QGC, and the parameters don’t appear.
I’ve tried reinstalling QGC to see if that would work and it didn’t.

I looked at this: Parameters & Configurations | PX4 Guide (v1.15)
And tried doing make parameters_metadata, but I still only see it generated for sitl. Tried flashing anyways and didn’t work.

I switched to getting the metadata to work for my target board. I did make cubepilot_cubeorange metadata_parameters (parameters_metadata yielded unknown target), and I was able to see the build directory had cubepilot_cubeorange_default. However, I didn’t see anything related to parameters. I then tried make cubepilot_cubeorange all_metadata and that build contained generated_params_metadata and had my parameters.
I then did a make on my board and uncompressed the parameters.json.xz in the etc/extras of the build directory and confirmed that I saw my parameters in there. I then flashed with QGC (Advanced settings with custom firmware file) and went into the .config/QGroundControl.org and checked the ParameterFactMetaData.xml and saw the parameters in there.

When I run param show -a in the nsh, I can see my parameters there, but I can’t see then in the Vehicle Setup->Parameters when I search for them.
Is there something that I’m missing?

2

I’m not sure what’s missing in terms of getting the param metadata to show up correctly in QGC. I’d have to dive deeper into it.

However, I assume you’re aware that you can just hardcode starting the sensor driver in the overall startup script rcS or in a board or airframe specific one.

And if you wrap it in a if, then, fi, it will continue the rest of the script if the sensor is not found and the start command fails.

3

Yeah I rolled that in already. I was mainly just hoping to be able to enable/disable it in the QGC params section instead of the nsh.

4

Ok.

@bkueng do you have any notes on how to make the params and param metadtaa available in QGC?

5

I think parameters should be ‘used’ by PX4 to be visible in QGC’s parameters tab.
Maybe there’s a better way to do that other than my “trick” described below:

I solve it by making the module run at least once in order for its parameters to show in QGC.
It doesn’t have to actively run. I’ve got a module that isn’t looped, it runs once and exits.
To have the parameters available, I added an extras.txt to the SD card to it runs once.

6

From what I see the only thing missing is adding it to the startup script and check the parameter MAX6675_ENABLE, like this: PX4-Autopilot/ROMFS/px4fmu_common/init.d/rc.sensors at 3c390952715d64c48fe8e32000b3aeb8a6f85f68 · PX4/PX4-Autopilot · GitHub