DIY Laser levelling using webcam and laser level

[Kitwn]

John,
Snap! I'm in the process of packing up our house in tropical WA at the moment ready for the move to a new property in Tasmania. Bought a nice place on 2 acres with a 6x6m shed just for me to play in without ever being able to go over and see it! Covid has made us all do things we'd never have believed possible a year ago.I'm sooooo looking forward to the cooler climate. I'll also be a quik ferry ride from Melbourne so Might make it over to your model engineering exhibition one year.

Not entirely sure if this is what you want, but the chip you might be looking for is possibly one of these. The acelerometer is mainly used to correct for drift in the gyro (or is it the other way round?) hence the combined unit on one chip. There's loads of software examples for using these beasties, mostly on threads about self-balancing machines. Let me know if thi is the right thing and I'll look up some of the info I have. I've got one of these chips as part of a long-term plan to build my wife a self-balancing wheelchair.

https://www.sparkfun.com/products/11028

Kit

[John McNamara]

Hi Kit

We are moving to the Hills outside Melbourne No Shed yet but room to build one. There is a big garage for now.

Thanks for the heads up on the IC chip, I would appreciate any feedback.
The levelling is needed to make sure the cutter head is truly vertical In X and Y. Before a cut is taken.
I thought for some time on this, It would probably work reasonably well without levelling, assuming the support rails were fairly straight. However reasonably is a word I would prefer not to use.

The way The machine will operate is to position the cutter head in X and Y before each peck.
Then using Joe's optical system position the Z at the wire before taking a peck down a known distance.

Regards
John

[Kitwn]

John,
I remember you mentioning something about this further back up the thread. I've come to realise that 'reasonably' is a word that fits more in my vocabulary than yours, or Joe's for that matter. Once I'm retired and settled into the new home I may well be making use of the sort of back-yard presicion that the pair of you are making possible for us mere mortals.

I've got a list of useful sites for software for that chip somewhere but not on this computer it seems. I'll try to find it and give you some links. Might be a few days though.

Kit

[Michael Gilligan]

Good to see you back, John

This design is only a single axis level, not a plumb ... but it might provide some inspiration.
https://www.allaboutcircuits.com/ind...leveling-tool/

MichaelG.

[Mud]

Just wanted to say thanks for the software - I used 0.26mm black fishing line and I would conservatively say I got my reference rail straight to within +/-5% of the line thickness with only manual adjustment (i.e. no fancy cams) without much bother. I did have trouble with reflections on the black line, so could not rely on the red/green/red gauge - I resorted to tape on my screen!

Image attached to show my lazy setup - whilst I wouldn't recommend ABS for metrology (nor my tape on the screen method) the idea clearly is a good one!

[leolfs]

Hi all,
first post.
If a digital output could be made available to indicate a when the wire is centered in the view field, then this would make a fantastic home switch for a variety of projects If coupled to say mach3. Presumably the axis would need to overshoot somewhat so as to detect the slope of the signal, but if this is consistent it would not matter. If all this could run on a RPi it could be a better alternative to any switch or sensor. .As this is beyond my skill level I wonder if the developer might be interested in adding this feature?
Regards....Leo

[John McNamara]

Hi Joe
Hi All

Also see previous post LeoLFS

If you are wondering what we have been doing while holed up due to Covid the following design has occupied us for quite a while. I am also halfway through moving house.

The attached images show the CAD drawings for a machine that uses a microscope and two suspended wires to generate a reference plane. The wires are tensioned by a heavy weight suspended in a container of oil. Gravity will assure that the wires are parallel and coplanar. Music wire is easily obtainable down to about 0.003inches. The thickness is consistent and accurate to sub microns.

A microscope on each side of the carriage is used to position a cutting head that is used to machine a plane surface on the workpiece. It is planned that this is done using software.

The spindle carries a small cutter 2 to 3 mm in diameter. It will have two modes: one a small peck cut, then a re-reference of the wires by the software and a small positioning move of about half the cutter diameter then a cut. This will be the slowest mode however due to the averaging effect of so many small measurements (not unlike hand scraping), it is expected that this will create a very high quality result.

The second mode will create a reset of the carriage on a line by line basis. This will be considerably faster.

The plane of the wire and the cutting plane are aligned. As shown, the moving crossmember carries a platform that is aligned to the wires. The main frame of the machine is 2 x 100mm square tubes. Yes, there are no precision rails: the crossmember rides on ball bearings firmly against the frame tubes. It is certain that the tubes will have a small amount of curvature as delivered by the factory that made them. It certain therefore that there will be a small “tramming” error as the carriage moves up and down the tubes. This has been considered carefully. With the small cutter diameter planned the tilt error will be very small. Remember that the cutter height is aligned to the wires. Commercial tube suppliers in Australia quote a straightness error of about 0.5mm per meter, so with a very large radius - 250m - the error will be very small indeed.

The machine has been designed to use laser cut 5mm steel, assembled by the tab and slot and bolt method. No welding will be used to avoid distortion. This method has proven itself in many past projects. The x across motion is guided by 500mm linear rails - these need to be shimmed straight. Drive is via a 16mm ballscrew. The total travel across is 220mm, however in most cases the machined surface will be between 25 and 50mm. As shown a 100x100mm workpiece is mounted Blue and Red. Using a different clamp tubes up to 200mm square can be accommodated.

The spindle motion in and out is mounted on 300mm linear rails. Travel is 120mm to allow for easy cutter changing. In use the total travel will be a few mm as the spindle moves in and out of a cut. It is driven by a 16mm ballscrew.

The carriage moves up and down the column using a 50:1 Asian worm drive gearbox (Not shown) and counterbalanced 20mm T2.5 synchronised timing belts.

All drives are step motors.
It was not intended to create a general purpose CNC machine. This allows a much-simplified drive system. Only the precision needed to create small overlapping cuts to create a flat surface was considered.

As you can see there are two people contributing to this machine design The CAD by myself and control system design by LeoLFS We have been mates for a decade or two. The machine is made possible by the excellent software developed by Joe,” Devmonkey”

For a single builder some of the parts can be reused in the final machine they build. Or better still a few enthusiasts can team together and share its use.
We are well on the way to assembling a prototype with many parts in hand.

Once the design is finalised I will place the plans on Grabcad.

Regards
John

[Kitwn]

Great to hear from you again John. I have now completed my move to Tasmania and am in the process of reasssembling my own machine on a new, more rigid frame in between all the other jobs that go with a new house and garden. I'll be using the taught wires method inspired by yourself again to get it back in 'reasonable' alignment. I think there's what may be described as a wide margin between your construction methods and mine but I follow your progress with great interest.

That looks like a machine that people might wish to borrow or hire once you have it made and working.

Kit

[John McNamara]

Hi All

Firstly, glad to hear you have moved to the Apple isle Kit, its a great place to live.
I have made the project open source.

I decided to open a GrabCAD page and have posted the CAD files there. I will update them as the design progresses. The model was built with AutoCAD 2017 so anyone with that version or later can view the files.

You can also download a free viewer from Autodesk. https://knowledge.autodesk.com/suppo...-TrueView.html

The files are located on GrabCAD here:
https://grabcad.com/library/machine-...linear-rails-1

Regards
John

[John McNamara]

Hi All
I uploaded version 28 to Grabcad replacing version 25
Regards
John