You’ll want a green line laser instead of a point one. Look for something around 532 nm with a wide fan angle (like 90°), those are usually used for leveling and should show dust on the floor nicely. Just keep an eye on the power so it’s safe indoors.
Fyi i have a 532nm mini green laser that projects a line, problem is, the line is to thin when shining parallel to the floor. I need a lens to basically make the laser line fatter to be able to show dust at least 300mm in front of me. Make sense?
