How do I use

I entered in picar-x/example to use the gray scale module.

But I don’t know by what standard the calibration is conducted.
There was no detail in the sunfounder document, can you explain it?

Is there a blue adjuster on your grayscale sensor. If so, use the screw to twist the adjuster and adjust the adjustment to the maximum. (Be careful to adjust according to the printed information)
If not, follow our tutorial link Calibrating the Grayscale Module step by step: