DIY Laser levelling using webcam and laser level

[mekanik]

Thanks for your efforts Michael, at least it looks like i should be able to get this running with the PC or Mac. do you have a link to the USB microscope you are using.
Kindest Regards
Mike

[Michael Gilligan]

You’re very welcome, Mike

As a hobby microscopist, and tinkerer, I have a number of cameras that I can use for what I am personally interested in doing with these applications ... but for the purposes of this thread, I think the ‘USB microscope’ linked earlier should be fine. https://www.amazon.co.uk/Microscope-.../dp/B07BF86SRP

It is claimed to work on both Mac and Windows, so is presumably a UVC webcam at heart
Note: UVC = USB Video Class and is widely supported.

Best Wishes
MichaelG.

[Michael Gilligan]

I’ve just found the manufacturer’s web page for the recommended USB microscope
https://bysameyee.com/microscope

Uncommonly helpful, I would say !

MichaelG.

[mekanik]

Thanks for that Michael
Just ordered one.
Regards
Mike

[unromeo]

Hi everybody,

First, please excuse my limited englisch, as it's not my first language.

I must say, it was a very interesting thread. I have read it from the beginning with great interest. Having the possibility to achieve these kind of precision with just a couple of items that most people have around the house is really mind blowing.

I am also in the process of planning and hopefully also building a fixed gantry cnc mill / router, but aiming at a smaller working area and more rigidity to be able to mill aluminium parts. The work area should be at around 300x300x150mm. I am still contemplating which material to use for the frame, but I might go for welded steel square beams and milled aluminium tooling plates for the surfaces to mount the rails. For now, I just have a set of 20mm chinese square rails and ball screws.

Anyways, while reading through the thread, I was always thinking to myself, why use the cheap USB cams with crappy sensors, when there is such a good Hi-Res sensor in the PiCamera, and the Raspberry pi is a great platform for such projects... but of course, a few pages down the thread and the Pi Camera was used.

A few years ago, I tried building a crude autoguider for astrophotography and used OpenCV and a Raspberry pi with a camera. It worked quite well, and it was able to track a light point while controlling a mount using 4 GPIOs. I ended using PHD guiding in the end, but the effort showed me what can be done with the openCV platform. I was thinking of using it to build almost the same tool that Joe put together in Java, but since the work has already been done, why not use his tool ? :)
By the way, is the development on the Raspberry platform still active ? I have a bunch of Pi's with cameras laying around the house, I could spare one for this project.

Another question: using a laser pointer of decent quality, would it work by shining the laser at a very shallow angle to the sensor, practically stretching the dot into a very elongated oval ? Has this been tried ? I think a forum member already suggested this. Or better yet ditch the laser and use fishing line / piano wire instead ?

Ok, I think it should suffice for a first post :)

Cheers !

[John McNamara]

Hi Unromeo
Hi All

A mate and I have been mulling over using a Raspberry Pi and Joe's excellent software.
Actually a pair of Pi's to position an XY positioning system probably using an Arduino to automate the process of generating a rail mount. It will use a simple cutting head that "Pecks" the surface to be flattened using a small cutter head. it will only need a small motor and the cutting forces will be very light so no big deal. The completed surface will look a bit like a scraped surface. The cutter head will be mounted on the rails that will later be used in the machine being built, these will be mounted on a temporary mount.
Maybe we could collaborate?

I am planning to design the device in 3D CAD with a primary objective of Laser cutting as many of the parts as possible out of Steel.

This will keep the costs very low. I would make the mechanical s open source.

Regards
John

[unromeo]

Hi Unromeo
Hi All

A mate and I have been mulling over using a Raspberry Pi and Joe's excellent software.
Actually a pair of Pi's to position an XY positioning system probably using an Arduino to automate the process of generating a rail mount. It will use a simple cutting head that "Pecks" the surface to be flattened using a small cutter head. it will only need a small motor and the cutting forces will be very light so no big deal. The completed surface will look a bit like a scraped surface. The cutter head will be mounted on the rails that will later be used in the machine being built, these will be mounted on a temporary mount.
Maybe we could collaborate?

I am planning to design the device in 3D CAD with a primary objective of Laser cutting as many of the parts as possible out of Steel.

This will keep the costs very low. I would make the mechanical s open source.

Regards
John

Hi John,

sure, if I can help with anything I will gladly do it, the only problem is that my programming kung fu is not that strong and that project was a while ago, but I can crawl my way into a working program if I want to. I can also assist in CAD and 3d printing if there is the need.

I wonder, if the measuring sensor is ofset from the pecking axis (the cutting head) won't that be an issue ?

I have a different idea how to measure the center of the laser line that won't involve cameras and PC's, but it will need to be tested for precision. I want to try something old school and very simple: analog electronics. Two small photodiodes placed aprox. 1mm apart (depending on the thickness of the laser line) so that each will catch the side of the line. Some op-amps to compare and amplify the signal and an analog microampmeter to display when we are at the exact center. Any difference in amplitude between the two photodiodes will be amplified and shown on the meter.
I have to buy a decent laser module and will test this out soon.

Regards,
Romeo

[devmonkey]

Hi John,

sure, if I can help with anything I will gladly do it, the only problem is that my programming kung fu is not that strong and that project was a while ago, but I can crawl my way into a working program if I want to. I can also assist in CAD and 3d printing if there is the need.

I wonder, if the measuring sensor is ofset from the pecking axis (the cutting head) won't that be an issue ?

I have a different idea how to measure the center of the laser line that won't involve cameras and PC's, but it will need to be tested for precision. I want to try something old school and very simple: analog electronics. Two small photodiodes placed aprox. 1mm apart (depending on the thickness of the laser line) so that each will catch the side of the line. Some op-amps to compare and amplify the signal and an analog microampmeter to display when we are at the exact center. Any difference in amplitude between the two photodiodes will be amplified and shown on the meter.
I have to buy a decent laser module and will test this out soon.

Regards,
Romeo

Just remember that there are no laser line generators that paint a straight line, for that you need a pentaprism which is v.expensive. So it depends what you are trying to do. I ultimately went to a taut wire system with the camera, worked very very well for me but I only used for straightening in 1D, a dot laser would have worked equally as well if you can mount it securely enough (which is extremely difficult). I used epoxy for generating the plane for the pair of rails to sit on.

Cheers, Joe

[Kitwn]

Romeo,
I ended up following Joe's route and going with taut wires (we actually owe John McNamara for that idea) but went even more old school and simple than you are planning using a simple electrical contact to detect when my probe was just touching the wire. Details here if you're interested http://www.mycncuk.com/threads/13627...ith-Taut-Wires

[John McNamara]

Hi All

Sorry I have not been around much we are moving house.

Below is a a few quick screen grabs of a concept design of a device to create a flat surface directly on the support tubes of a CNC router.

Apart from the long tubes the device is approx 270mm square.
I plan to reduce it down once I sort out how big the sensors need to be. The laser cutting will be cheap its all 5mm Plate.

Note the X and Y 12mm ball pairs used to level the platform, allowing it to rock X and Y.
In practice the pocket corners will be formed by Lightly pressing them in together in a vice, They will be very accurate.
Not shown will be some springs to keep them pressed against each other.

The drives for the X and Y rock will be at the bottom of the tube if a plumb bob is used.
Huge leverage so small steppers only will be needed nothing fancy just a threaded rod there will be little travel needed.

Again just a few of 5mm laser cut plates to mount them.

Do you know of a cheap IC chip that could be used instead of the plumb bob? I know they exist but where?
The wire alignment microscope as per Joe's design will be mounted on the vertical carriage.

I am not planning to use ball screws for the X and Z (Remember the Y is A belt), just the threaded rod drives used in 3 D printers. Quite cheap.

There will be a single wheel only carriage that rides on the opposite rail for stability
I have not shown the drive for the carriage itself It can be a timing belt Better or just a cable drum.
I have shown Ali Barba Bearings.

What do you think?
Regards J