DIY Laser levelling using webcam and laser level

[devmonkey]

Ok so just talking about testing whether the line generator generates a straight line. Although the thing is self levelling it definitely wont be level wrt to earth within the resolution of the sensor and we don't really care about our axis being planar wrt earth, rather to each other.I understand you use the water level to check the work lasers are planar to earth but how do you check the projected lines are straight?

Would you suggest sampling the projected line against an earth reference (using a water level and a microscope) at a number of points then calculating a best fit line. Then take the error between points measured and this best fit line to determine straightness? How straight are the laser line generators your work with?


If I had a long precision edge I could just do the same thing with that, unfortunately I don't...


IDEA (EDIT)
Could be done in two stages with the current setup, first setting a rail to be straight wrt to the laser by sending the beam along the rail then using the now straight rail to check the line laser is straight with the laser positioned orthogonal to the rail.



Cheers.