Optics B/C

Froggie
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Re: LSS: how to get the correct angle of the laser reflection

Postby Froggie » Sat Dec 02, 2017 12:14 pm

home2mars wrote:Hi all,


After days of trying and getting really frustrated, maybe this forum can help. I have not used the box yet. So the setup is just on the table.
The table is as level as I can make it. I have printed the protractor templates (from document I found ___ forgot exactly, but the title is "Setting up for the Laser Shoot.docx"
I also use graph strips.

I angle the first mirror 45o using the protractor template above (location: on the middle line, about 2 inches in front of the laser)
Then using the graph strips to find where the laser reflection should be and then place a second mirror there.

As simple as that. BUT for the life of me, for days I can not even get the laser beam to correctly fall in the middle of the second mirror.
It is always off by 3-4 millimeter and that is enough to create big enough error that I can not even hit the third mirror.

Anything I do wrong? How to accurately angle the mirror(s) and then getting a correct angle to position the "catching" mirror.

Thanks!

A picture might help...
For the 45 degrees part you might want to use a 45-45-90 triangle to be more accurate.
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Re: LSS: how to get the correct angle of the laser reflection

Postby home2mars » Sat Dec 02, 2017 2:32 pm

Image
how to upload picture

Basically getting a consistent reflection from mirror 1 to mirror 2 is impossible for me.
Just simple 45 degree angle for mirror 1 and consistently got reflected to the MIDDLE of mirror 2
This middle requirement is important because that's where I need to start the graph strip to mirror 3 which is usually the longest path
Either my protractor template is garbage or my mirror is garbage or I make fundamental mistake.

Where can I buy SMALL (tiny to be precise) 45-45-90 triangle? and then how to use it to accurately place mirror 1?


Thanks

PS: in the picture, thing do not look straight but this is just for photo purposes. I did not redo the line up to take this photo.
But I hope you get what I am trying to do


Froggie wrote:A picture might help...
For the 45 degrees part you might want to use a 45-45-90 triangle to be more accurate.

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Re: LSS: how to get the correct angle of the laser reflection

Postby kenniky » Tue Dec 05, 2017 2:31 pm

home2mars wrote:Image
how to upload picture

Basically getting a consistent reflection from mirror 1 to mirror 2 is impossible for me.
Just simple 45 degree angle for mirror 1 and consistently got reflected to the MIDDLE of mirror 2
This middle requirement is important because that's where I need to start the graph strip to mirror 3 which is usually the longest path
Either my protractor template is garbage or my mirror is garbage or I make fundamental mistake.

Where can I buy SMALL (tiny to be precise) 45-45-90 triangle? and then how to use it to accurately place mirror 1?


Thanks

PS: in the picture, thing do not look straight but this is just for photo purposes. I did not redo the line up to take this photo.
But I hope you get what I am trying to do



Are you sure your laser is perfectly straight?

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Re: LSS: how to get the correct angle of the laser reflection

Postby Froggie » Tue Dec 05, 2017 3:50 pm

kenniky wrote:
home2mars wrote:Image
how to upload picture

Basically getting a consistent reflection from mirror 1 to mirror 2 is impossible for me.
Just simple 45 degree angle for mirror 1 and consistently got reflected to the MIDDLE of mirror 2
This middle requirement is important because that's where I need to start the graph strip to mirror 3 which is usually the longest path
Either my protractor template is garbage or my mirror is garbage or I make fundamental mistake.

Where can I buy SMALL (tiny to be precise) 45-45-90 triangle? and then how to use it to accurately place mirror 1?


Thanks

PS: in the picture, thing do not look straight but this is just for photo purposes. I did not redo the line up to take this photo.
But I hope you get what I am trying to do



Are you sure your laser is perfectly straight?

That might be a problem.
Try using the box and doing the same setup?
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Re: LSS: how to get the correct angle of the laser reflection

Postby home2mars » Wed Dec 06, 2017 6:45 pm

Froggie wrote:That might be a problem.
Try using the box and doing the same setup?



It is perfectly straight.

The box? Forget it, THAT is even worse because I can not get the laser to be straight!
On top that the box is not 100% straight, I can not get the laser to be stable in its holding contraption (per instruction I found at soinc.com)
Anyway, I do not think anyone can help. It is way too random.
Same setup, just changing the mirror, gives different angles.
So not moving anything, but swapping mirror (labeled 1 at the photo) with the other 3 mirrors (mirror 3,4,5) resulting completely different ending at mirror 2.

Put a bubble leveler to all mirrors to make sure it is perfectly straight, etc etc etc.
It is just way too random to be useful.

Just hope for luck during competition.


EDIT: having multiple people putting the protractors and resulting to widely different result.
I think the bottom line is that the whole thing is way too sensitive to be "practiced" on.
A slight (like maybe 1/16 of millimeter) imperfection in the lining up the protractor, putting the mirror down, trace the reflected ray to the subsequent mirror resulting an outsize mistake.
Repeat that 5 times/mirrors. A herculean task for us (6th graders and their moms).
Last edited by home2mars on Wed Dec 06, 2017 8:03 pm, edited 1 time in total.

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Re: Tempate for LSS

Postby home2mars » Wed Dec 06, 2017 7:29 pm

Rule: " Participant tools / templates may remain on the LSS during this process "

Wiki: https://scioly.org/wiki/index.php/Optics
Templates
Templates are often used in the Laser Shoot, and can range from basic graph paper to complicated printed templates. These templates must be able to accommodate the barrier mirror, whether they have a hole in the center or are split into multiple parts. Also, they must fit into the LSS box.

Templates vary in complexity, depending on how many points competitors are attempting to achieve. A simple 45 degree concept utilizing 4 mirrors can be very simple and accurate, but sacrifices 9 points of the lab score. A more complex design can be used to enable use of a fifth mirror, gaining an additional 4 points. Some templates may also be designed to use the barrier mirror, but require more fine-tuning as not all angles will be known beforehand.


QUESTION:
Does the WIKI saying that we can cover the majority (if not the entire) surface of the LSS (the board, inside the box) with graph paper with lines and locations where the 4 or 5 mirrors could just be placed without using protractor anymore?

For example: putting this kind of template inside the box (for this thread sake, please ignore that there is 8 mirrors in the template, instead of 5)
Image
online free photo storage


Of course, we do not know where the target is, but with 4 mirrors planned, that could be easily modified at the last minute.
If the team plan to use 5 mirrors, maybe just put a big graph paper on the surface.

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Re: Tempate for LSS

Postby Froggie » Wed Dec 06, 2017 7:58 pm

home2mars wrote:Rule: " Participant tools / templates may remain on the LSS during this process "

Wiki: https://scioly.org/wiki/index.php/Optics
Templates
Templates are often used in the Laser Shoot, and can range from basic graph paper to complicated printed templates. These templates must be able to accommodate the barrier mirror, whether they have a hole in the center or are split into multiple parts. Also, they must fit into the LSS box.

Templates vary in complexity, depending on how many points competitors are attempting to achieve. A simple 45 degree concept utilizing 4 mirrors can be very simple and accurate, but sacrifices 9 points of the lab score. A more complex design can be used to enable use of a fifth mirror, gaining an additional 4 points. Some templates may also be designed to use the barrier mirror, but require more fine-tuning as not all angles will be known beforehand.


QUESTION:
Does the WIKI saying that we can cover the majority (if not the entire) surface of the LSS (the board, inside the box) with graph paper with lines and locations where the 4 or 5 mirrors could just be placed without using protractor anymore?

For example: putting this kind of template inside the box (for this thread sake, please ignore that there is 8 mirrors in the template, instead of 5)
Image
online free photo storage


Of course, we do not know where the target is, but with 4 mirrors planned, that could be easily modified at the last minute.
If the team plan to use 5 mirrors, maybe just put a big graph paper on the surface.


Any type of template is allowed, so the graph paper with lines is allowed too. You just have to account for the barrier and the size of the box (since you can't lift up the barrier).
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Re: Optics B/C

Postby SawnEcho » Fri Dec 08, 2017 8:20 pm

Will the laser shoot barrier have a mirror on it?

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Re: Optics B/C

Postby Froggie » Fri Dec 08, 2017 8:24 pm

SawnEcho wrote:Will the laser shoot barrier have a mirror on it?

Yes, but it can be on either side of the barrier.
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Magentic or not?

Postby dmackSD » Sun Dec 10, 2017 9:37 pm

We have been requesting guidance from our regional organizer about whether our LSS board will have magnets or not. I know the rules say that a "black surface with ferrous metal component ... is recommended". It is my understanding that is was not "required" b/c some proctors may not be able to achieve that.

However, it seems that it should be fair for the teams preparing for their own regional should have some guidance for how their events will operate. The strategy could be different whether you have more stable magnetized mirrors or not. Similarly, knowing whether the surface is black or not, has an impact in strategy.

What do you guys think? fair request for all to receive guidance for a regional events?

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Black surface

Postby dmackSD » Sun Dec 10, 2017 9:39 pm

Second question;
If the surface is black, how will the centerline be provided?

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Re: Optics B/C

Postby dmackSD » Sun Dec 10, 2017 9:43 pm

Final comment for today. This website can be helpful to simulate different solutions. I made some test cases for the kids to try out. Files can be saved. In these cases, mirrors reflect on both sides, so just come up with a way to indicate which side is reflective. Clearly some can hit all three mirrors, but other setups only allow you to hit 2.

https://ricktu288.github.io/ray-optics/simulator/

Enjoy!

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Re: Optics B/C

Postby jajefan » Mon Dec 11, 2017 1:20 am

I’m surprised no one has mentioned this, but here’s a very important question:

When the barriers are placed, will they always be perpendicular to the line of sight from the perspective of the mirror? As in, will they always be at 90 degrees with the laser, or Can the ES place them at any angle relative to the laser? Because there’s a huge difference in strategy in preparing for clear cut 90 degree or 45 degree mirror angles for barriers vs having to use a protractor to measure what angle the ES decided to place the barriers (or would they tell you?)

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Re: Optics B/C

Postby Froggie » Mon Dec 11, 2017 1:23 am

jajefan wrote:I’m surprised no one has mentioned this, but here’s a very important question:

When the barriers are placed, will they always be perpendicular to the line of sight from the perspective of the mirror? As in, will they always be at 90 degrees with the laser, or Can the ES place them at any angle relative to the laser? Because there’s a huge difference in strategy in preparing for clear cut 90 degree or 45 degree mirror angles for barriers vs having to use a protractor to measure what angle the ES decided to place the barriers (or would they tell you?)

The ES can place it at any angle. It can be at 90 or 45 or 3.141592 (theoretically) degrees.
I don't think they'll tell you, but some might.
Check out the rules.
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Re: Optics B/C

Postby Hartman » Fri Dec 15, 2017 2:23 am

dmackSD wrote:Final comment for today. This website can be helpful to simulate different solutions. I made some test cases for the kids to try out. Files can be saved. In these cases, mirrors reflect on both sides, so just come up with a way to indicate which side is reflective. Clearly some can hit all three mirrors, but other setups only allow you to hit 2.

https://ricktu288.github.io/ray-optics/simulator/

Enjoy!

This is amazing!


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