New or old.. but I dont understand how a Laser can tell distance
... there are mainly two methodes - most used is "trianglation", where a camera detects the exact position of a laser spot "off-axis" to the camera, so there's a displacement relative to the distance.
The other methode is "Time Of Flight" - here a super-short laser pulse is emitted and the time until the reflection is detected in a sensor near to the emitter is direct proportional to the distance of the reflective spot on a surface ...
Viktor
Aufruf zum Projekt "Müll-freie Meere" - https://reprap.org/forum/list.php?426
Call for the project "garbage-free seas" - https://reprap.org/forum/list.php?425