Whenever you need to measure the size, breadth, or depth of an object, there are many devices for the job. You can begin with a tape measure, transfer as much as calipers in the event you want extra precision, or possibly even a micrometer if it’s a very important dimension. However what if you wish to understand how flat one thing is? Is there one thing apart from a straightedge and an eyeball for assessing the flatness of a floor?

Because it seems, there may be: a $15 webcam and an inexpensive laser stage will do the job, together with some homebrew software program and a little bit little bit of persistence. At the least that’s what [Bryan Howard] got here up with to assist him assess the flatness of the gantry he fabricated for a big CNC machine he’s engaged on.

The gantry arm is constructed from metal tubing, a commodity product with loads of dimensional variability. To measure the microscopic hills and valleys over the size of the beam, [Bryan] mounted a lens-less webcam to a block of metallic. An inexpensive laser stage is about as much as skim excessive of the beam and shine throughout the digicam’s picture sensor.

On a laptop computer, photographs of the beam are transformed into an depth profile whose peak is positioned by a Gaussian curve match. The situation of the height on the sensor is recorded at varied factors alongside the floor, resulting in a map of the microscopic hills and valleys alongside the beam.

As seen within the video after the break, [Bryan]’s outcomes from such a quick-and-dirty setup are spectacular. Regardless of some wobblies within the laser beam due to its auto-leveling mechanism, he was capable of scan the complete size of the beam, which seems prefer it’s greater than a meter lengthy, and measure the flatness with a decision of a few microns. Spoiler alert: the beam wants some work. However now [Bryan] is aware of simply the place to scrape and shim the floor and by how a lot, which is an entire lot higher than guessing.