Consider using a hall sensor to read rpm and/or speed

[slabua]

[slabua]

Might be linked to #20

[slabua]

The RPM signal from ECU appears to be a 12V pulse signal of about 100Hz/1000RPM.
More investigation on the matter will be done in due time.

[slabua]

Might be easier and more accurate to read the speed via a gps module for the Pico.
If not, go back to the hall sensor idea.