[PWalsh] has a clever idea for learning and experimenting with basic optics: instead of using actual lenses, he’s using clear pieces of laser-cut acrylic cut into lens profiles instead. They are much easier to make, mount, adjust, and handle while still bending light in the same basic ways. It allows for simple hands-on experimentation with plenty of visual feedback – perfect for beginners.
This idea is part of [PWalsh]’s low-cost optics bench project, which uses laser-cut plastic to create adjustable optics bench components. We’ve covered this project before, but [PWalsh] expanded the idea with the concept of these simple laser-cut optics for basic experimentation; an addition that requires no additional tools and only a small amount of material. Features and value added for nearly zero cost is something we always love to see!
This isn’t the first attempt at low-cost optics lab work. Check out this LEGO optics lab.
Lasers without sharks? How is that even possible?
I know, eh? They wanted to see if they could without stopping to wonder whether they _should_…
i believe this is the pre-shark test.
using lasers for lasers… we’ve gone too far
Woot! That’s my team’s project!
The files aren’t available yet because I encountered a problem specific to the CAD program I’m using. Curves in “saved” files are curves, but exported as DXF files they become polylines. I can cut curved pieces, but when you cut from DXF files the curves are faceted.
Our CAD expert is looking into this and should have well formed files soon, and then they’ll go up on the GitHib account and the Hackaday.io page.
(Also, we’re cooking up something special for the “Citizen Scientist” interim prize, and that’s taking up a lot of time. Check the project page for updates.)
I use high count polygons (720 facets + ) and the edges look smooth.
thought of using smoke/vapor to make rays visible (in reduced lighting) and use bent pieces of plexi as lenses for even cheaper?
It looks great! Just how much post-print work has to be done?
(Can’t watch video at the moment.)
None. Cut them and use them.
If you need magnets then those have to be installed, but optically they’re good to go right out of the laser.
(Be aware that these are not optical quality, and are mostly for a high-school student or younger to play with.)
cant you just smooth the edges with a belt sander or buffing wheel?
Tell me the format of saved file and I can tell you the correct method of saving the file in the correct way. Nope, I’m serious if you are using .STL you will always fail..
Are there any plans to sell the pre-cut parts as kits for those of us without access to a laser cutter?
If you want some, contact me on .io and I’ll send you a set. In return, you can give us some feedback on how they work out.
We’re *considering* making a run of 100 kits at the end of the project. (One of our members is really interested in doing this.)
We’ll probably post a question asking how many people would be interested in purchasing such-and-so for this-amount and see if there’s enough interest to make/sell the 100 units.
(I’m not in love with the idea, but if there’s community interest I could be convinced.)
Wouldn’t it be even simpler/cheaper by making a mold for a flat rectangular prism and turn it into a fresnel lens? Sure it is more difficult to see/understand what’s happening if you are using it to teach people, but it is by far cheaper and easier to make.
Does the slightly conical kerf of the laser cause any issues? I can imagine the beam being deflected up or down slightly. If you have access to a CNC mill then that might produce slightly better results. Also, if you use g code then a G2 or G3 move should produce a nice curve.
These are not anywhere close to optical quality, they’re mostly for [team member] John’s 12-year old daughter to play around with and get an understanding of light rays.
The conical kerf isn’t as much of a problem as the faceting. If you look closely at the binoculars part of the video, the negative lens scatters the light while the positive lens focuses it. That’s a direct result of the faceting, and it’s because when I was building the profiles I exported/imported that curve segment so that I could use the same segment for multiple lenses.
I have to say, when I first slid the single beam up and down in the first part of the video I got a better understanding of the focal point than I had beforehand.
Fantastic! This could be a huge boon to grade school science educators who can’t afford (or whose district can’t afford) proper lens sets. Significant marketing potential to the whole educational resources marketplace, assuming someone else hasn’t already done something like this. Congrats on the great idea!