Laser beam help

[Wizpic]

I have a laser dot beam 635-655Nm and want to use it to measure a lean on some equipment at different heights.
The idea is I use a  laser dot beam by attaching it to a beam then raise the lift and record the difference measurements to be able to calculate the lean to make sure it's with then manufacturer specification (tolerance).

For the calibration and test process I've got a true 90 degrees flat steel beam that the laser beam attaches to with magnets but it's not worked as expected. With the laser beam set at say 1.5 meters and the measurement from the steel beam is 75.00mm and then move it up 3.5 meters the measurement moves from 75mm to 85-90mm, Which I where i would of though it should be the same measurement regardless of the height.

I've attached the good old fashion plumb bob(line) to it and the plump line measurements remain the same at all heights so I know the steel been is true and plus it has been checked with a digital level which as been calibrated.
The first picture beam 1 is what I've used and the holding part has been made by an cnc machine and lath. So I know it's true , The second picture of the laser beam is What I looking into if it's any better ?
The last picture is of the steel beam set up to give you more of an idea.
I know i could use the good old fashion plumb bob but some conditions in doors there could be a slight breeze which moves it about Plus to make it quicker and easier I want to attach a laser on each corner (left and right) to do one lift rather than 6-8 lifts if I only used one.
Any thoughts if I'm thinking along the lines or looking at it wrong ?

[xor]

all things goes wrong when you attach your laser in a rigid way...you need to simulate the plumb bob
you need something like this https://www.youtube.com/watch?v=4uUfCNIG61o
...or some thing like in my sketch

[Wizpic]

Logical thinking would lead you to think that if the beam is straight and fixed to a steel beam which does not move height should not make a difference.
I’ve looked at the hem laser plumb lines which may work great but this won’t fixed and watching the video you can lock of which to me is the same thing that I’m trying to do.

[sfiga69]

are you sure the laser is aligned with the container?
rotate the laser 90°, 180° and 270°  on its axis and repeat the measurements
10mm to 2000mm is an angle of 0.29°

[xor]

you make two measurements...one at 1.5m and other at 3.5m...so, when you take first shot that is reference and while you go up the errors get adding to the value of second measurement
...you can even make a statistic with errors...something like mm/10cm or so
all this because the laser ray isn't perfectly parallel with the steel beam...to do this parallelism, you need to help by the gravity, like the plumb bob, ... and let the laser to autocentrate

[pickit2]

the laser you show in 6mm form, it has a lens that is used to focus the beam, a few years ago,
 I was using one in a project, it was not an issue but the beam was deflected by a small amount.

sfiga69 posted to rotate the unitby 90°, 180° and 270° this would show if this was the problem.
plus what about in use, ie: knocked obstructed, maybe use two lasers.

also 10mm at 2000mm is an angle of 0.29° not checked but that looks about right, for not being such a problem.

have you thought about a digital level ic / unit, this would work at any height.

[Wizpic]

I’m looking at a pan/tilt kit with Servos and a adxl355 or the mpu6050, but leaning towards the adxl355 or 354, this should put it right
The maximum height of this will be 10-12 meters starting from about 1 meter to floor level.
I’m only using the steel beam as a test/setting it up to make sure it works as it should.
I’m waiting on my laser’s to arrive to do but more testing before the pan/tilt method.
Made new holding brackets to fix the laser too.

[hosmis]

" adxl355 or the mpu6050, but leaning towards the adxl355 ....  " they are not suitable they are not stable ..

SCA100T 
SCA3100-D04
SCA61T
SCA610
SCA103T

SCA103-D04..D05 differential inclinometer , Analog output resolution  0.0013 ° .. 100mt to 2.26mm

[Wizpic]

I’ve tried searching for those and they seem no longer to be manufactured or stocked, looked on e bay but hard to get ur expensive.
Thanks for the heads up on those others I where going to use I’ll have to do some searching for others

[hosmis]

no problem in stok I use it all the time

https://www.aliexpress.com/af/sca103t.html?d=y&origin=n&SearchText=sca103t&catId=0&initiative_id=SB_20210517110331

https://www.aliexpress.com/af/sca610.html?d=y&origin=n&SearchText=sca610&catId=0&initiative_id=SB_20210517110413

https://www.aliexpress.com/af/sca61t.html?d=y&origin=n&SearchText=sca61t&catId=0&initiative_id=SB_20210517110440

[hosmis]

https://www.aliexpress.com/item/32669429836.html?spm=a2g0s.9042311.0.0.72f64c4dIzM4zH

https://www.aliexpress.com/item/1005001890384083.html?spm=a2g0o.detail.1000060.3.5d361ebdUkj5hz&gps-id=pcDetailBottomMoreThisSeller&scm=1007.13339.169870.0&scm_id=1007.13339.169870.0&scm-url=1007.13339.169870.0&pvid=656b8bc3-9b1e-4dbd-bffb-2fcbf32e4e55&_t=gps-id:pcDetailBottomMoreThisSeller,scm-url:1007.13339.169870.0,pvid:656b8bc3-9b1e-4dbd-bffb-2fcbf32e4e55,tpp_buckets:668%230%23131923%2394_668%230%23131923%2394_668%23888%233325%231_668%23888%233325%231_668%232846%238109%231935_668%235811%2327186%2372_668%232717%237562%23409_668%231000022185%231000066059%230_668%233468%2315617%23809_668%232846%238109%231935_668%235811%2327186%2372_668%232717%237562%23409_668%233164%239976%23391_668%233468%2315617%23809

[Wizpic]

I’ve looked at those and not really suitable for what I want to do.
But thanks
I’m looking at the newer design of those chips the SCL3300 range with spi interface, just looking through the data sheets S and comparing them

[Wizpic]

My new type laser's have come and yes I now see the trouble when you attach it to a solid object there is a difference in the measurements at different heights, Which is mind blowing when you think about it. placing it on a flat surface and pointing it at a wall and moving it along the wall the line is same measurement from the floor up to the laser line along the wall(drawn a line along the wall), Now on the same surface I move back say 1.5 meters and repeat same process I get a difference of 12mm between lines ?.    

so I've been doing a bit more research in using a pan and tilt system so vertically it will always be 90 degrees,  A bit like a plump bob line I guess but  digitally controlled with servo's. I came across this

 https://toptechboy.com/9-axis-imu-lesson-22-how-to-create-a-tilt-stabilized-platform-with-arduino/

Looks interesting and smooth operation his uses an BNO055 Adafruit 9-DOF Absolute Orientation IMU Fusion sensor with a pan and tile kit
.

Would something like this work as a plump line laser you reckon ?
EDIT: I may have jumped the gun on the BNO055 as the magnet and steel would effect the readings just been watching more of his videos and he mentioned about magnet effecting the readings, Got a bit exticed when I seen this first video which was No.24

[solutions]

I'm at a loss to understand what the laser is for - if you're going to measure tilt, measure tilt

[Wizpic]

I'm at a loss to understand what the laser is for - if you're going to measure tilt, measure tilt

It will be to measure a lean (if any) on a lift as the good old plump bobs move around to much as in places even though in doors there can be a slight breeze traveling through the building.
So the idea is the laser will show dot on the floor and then raise the lift and see how far the dot moves away from the last marked dot on the floor.
This then can be used to calculate the lean. But the trouble at the moment using a true 90 degree steel beam for testing the higher I move it up the dot moves away from the starting point as I would of expected that it should be close or the same distance but is not

[solutions]

But a laser has no clue of where the center of the earth is, so you cannot use it directly to compute "lean" (in a lift, you want it to be plumb).

Why can't you mount the laser to the FLOOR, then adjust the UPWARD beam laser to be plumb ONCE (using your I-beam or a plumb bob), from which point you shine the laser on a translucent horizontal panel you attach to the side of the lift near its top. If it leans the beam will move on the screen (translucent panel) as the lift goes up.

I am assuming here you are doing a factory QA/lift-adjustment and not requiring this to be portable.

[Wizpic]

It’s not for pointing up, the laser will be pointing downwards to the floor. So at low level the laser will shine a dot on the floor then a marker line placed and then raised 1 meter the checked against the dot of the staring point  then raised upto 6-10 meters and following the same process.

[solutions]

I know.

You are stuck in a paradigm & need to erase what's in your head as a solution - the approach won't won't work because the laser may be straight, but it has no idea where the center of the earth is because you never referenced it to anything but wherever it hits the floor.

You have to calibrate the beam when it is attached to the floor to point UP (plumb). You can't point it down at anything because there is no reference to plumb. Then you can move the lift up and down and measure relative to that beam...I suggested shining it onto a horizontal translucent screen on the lift

Pointing a laser at the floor does nothing but draw an arbitrary line from the laser to the floor. Do you have ancestors from Pisa? 

[solutions]

@Wizpic - any progress?

[Wizpic]

Not yet, kind of giving up on the idea and considering doing it the old fashion way with plump bob, The ready built laser levels point upwards and not downwards. So thinking of trying one of those and placing a plate on it with makers and try that.