Rotary Laser level detection

Hi,
I have a small chain trencher, the kind that you would use to put in a sprinkler system. I would like to use it to put in drainage systems which require an accurate slope for the bottom of the trench. I can input a slope into a rotary level laser and I would like the depth to match. I am thinking of using a raspberry pi 4 for control, but I don't know what sensor I should use. I would like to use the same units in the readily available detectors like dewalt, johnson or leica.

Use a simple gravity angle sensor like this (if you are using arduino or RPi).

If you mean a laser sensor then you could use an array of Ldr's.

Whenever I do anything like this I use a clear tube with coloured water in as a level. Attach the tube to a stick at each end, place next to each other and mark the water level. If you want your second stick to be 1 inch lower than the first then the water level should be 2 inch higher than the mark.

Mike.

The array of LDR's sounds perfect. Can you recommend a manufacturer, part or even an appropriate search term. I keep finding chips that are really expensive when a search on google.