Expose raw rgb values

[DrTom]

We found it valuable to (sometimes) work with raw RGB values instead of HSV/HLS for the following reasons:

• Teaching how a color sensor works internally.
• Also teaching how to write a color matcher from scratch is much more straight forward.
• In some cases using raw RGB gives more control and better results.

Here is a patch https://github.com/DrTom/pybricks-micropython/commit/09b9b161ed3aab4b7865231bc619bd324e452b04 which implements this for the colorsensor provided with the spike sets.

Would you be interested in a pull request or maybe add this on your behalf to pybricks?

As for a PR: I have no idea how good this implementation is. It works though. I have access to the ColorDistanceSensor and could try to extend it for that one, too.

[laurensvalk]

Nice! To access raw values, you can also just use the existing PUPDevice class.

Since you can use it in Python, you could fairly easily extend the color sensor class that way without building a custom firmware. https://docs.pybricks.com/en/latest/iodevices/pupdevice.html

You can also experiment with all the modes that way to see what they do.

Would you be interested in a pull request or maybe add this on your behalf to pybricks?

Thanks for offering this. I think we'll stick with the unified HSV approach across the API, and provide the PUPDevice class for any customization.

[DrTom]

Thanks for pointing to the generic PUBDevice. Here is an example how to read the RGB values (maybe it is useful for somebody in the future):

from pybricks.iodevices import PUPDevice
from pybricks.parameters import Port

PBDRV_LEGODEV_MODE_PUP_COLOR_SENSOR__RGB_I = 5  # read 4x int16_t

color_sensor_device = PUPDevice(Port.F)
r, g, b, _ = color_sensor_device.read(PBDRV_LEGODEV_MODE_PUP_COLOR_SENSOR__RGB_I)
print(r, g, b)

Much easier than building a custom firmware I guess. Getting the proper mode constant might be the trickiest part; e.g. here https://github.com/pybricks/pybricks-micropython/blob/6d1d9050b23a4bdc5ab426a12965b2f69946b7ae/lib/pbio/include/pbdrv/legodev.h#L316

[laurensvalk]

For further experimentation, have a look at the ambient HSV mode :)