Instructables

Mechanical iris v2.0

Before anything else, I would like to say that this Instructable is based on and inspired by carlbass and his Mechanical iris.

Author: http://www.instructables.com/member/carlbass/
Instructable: http://www.instructables.com/id/mechanical-iris-1/

Inspired by his work I quickly put a piece of plywood in my desktop laser cutter and set it to work. Minutes later the promise appeared, and within moments I had pieced everything together in a fully functioning mechanical iris. Awesome!

However, after admiring the design I spotted few ways in which I felt it could be improved.

So here it is; my take on the Mechanical iris (v2.0).

 
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Step 1: Improvements

Picture of Improvements

- In the original Mechanical iris there were three layers. I felt this was excessive and so this new design offers only two (plus 1mm for the optional Perspex cover).

- The points at which the 'arms' attached to the blades relied on a shared pin to partially rotate about. This aspect seemed over complicated when the same effect could be achieved with clever cutting. This means that post cutting assembly time is reduced.

- The holes have been changed to fit 6mm dowel instead of 5mm which, for some reason I found stupidly difficult to obtain.

- Drawing pins have been used to cap the wooden dowel pins ensuring that the blades and outer ring do not wonder or come off. This design does not however ensure the arms are kept in place when holding the finished product upside down. This is where the optional 1mm Perspex cover comes in should you feel you need it.

- Although this last part is very crude in its current design, I have included a use for the offcuts. Stuck together they form a raised grip for the back of the iris enabling you to hold and manipulate it more easily. This will prove its worth when you come to 'working' the outer ring in for a couple of minutes.

Step 2: Materials

Picture of Materials

Wood glue
Drawing pins
Your choice in wood
6mm dowel
Scalpel / hobby knife
Ruler

1mm colourless Perspex (optional)

steveastrouk3 months ago

Great piece. I've been playing with it to use flexing arms from the outer ring to the petals, and having no moving joints except the outer ring.

NTT (author)  steveastrouk3 months ago
That's an interesting idea. I'd like to see some pictures of that
steveastrouk NTT3 months ago

I'm Struggling with materials....thin laser ply is useless.....I might try PET-G

siluentas3 months ago
it looks fantastic
NTT (author)  siluentas3 months ago
Thank you :-)

Hi I am cutting with visicut, DXF or SVG is welcome :-D

NTT (author)  Manfred.Overmeen3 months ago
ok. I'll see what I can do.
Nobin4 months ago

Muito Legal e engenhoso

Very nice ! I will add to my homework project

Thanks

alienfap4 months ago

Hi.

Nice project.

However, I cannot get the .DWG file to download. I am referring to the file Mechanical_Iris_v2.dwg. Can anybody help me to download this? I'm wondering if this is my screw-up (likely) or if the link is not working.

Thanks.

Mark Rehorst4 months ago

Very nice!

I spent some time searching for basic iris design information several months ago and never got anywhere except for a few that people had created and posted in various places around the web. When I couldn't find anything I tried to come up with a set of mathematical rules that would allow designs to be automated using a spreadsheet but never got very far with it. I wanted to input variables like the number of blades and maximum opening diameter and have the thing calculate blade size and shape and locations of hinge pins and actuator pins. Needless to say, its a very complex problem and I never got very far with it. I was unable to locate any old books that had any iris design info in them.

There seem to be two major types of irises, those with non overlapping blades like yours, and those with overlapping blades like those commonly used in camera lenses. Overlapping blades leads to a convex, polygonal center hole and requires multiple layers due to the overlap. They can't close completely because of the overlap though it's possible to add a shutter leaf on a final layer that will close off the remaining center hole. The blade's edges rub against each other so plastics or metals would be the best materials options for them. The non overlapping blades type can close completely and have complex hole border at all positions except fully open or fully closed, making them less useful for windows/covers where you might want a partial opening.

I was thinking it might be possible to use cloth blades with elastic cords in the edges, the ends of which are attached to the fixed and rotating rings.

If anyone knows of any technical references of the design of irises I love to know about them.

Beautiful!

I'm thinking of ways to change the design to make the border (which contains all of the mechanics) around the hole as small as possible. If this would be the frontdoor to a house, and the diameter of the hole is 2 meters (6.56 feet), the ring would extend two meters around that, including into the ground. There has to be a way to minimise this.

NTT (author)  perpetualrabbit4 months ago

You're absolutely right. This design is limited because it does not overlap. As a result and as can be seen, everything must be spread out around the centre. To get past this you should be looking at an over-lapping iris. Something like this:

http://www.instructables.com/id/Paper-Iris-Glasses/

This one works well because the mechanism isn't restricted to one layer (the blades are also very thin by comparison). This would work best in thin metal and with a lot of oil.

Hope that's food for thought. And thank you for the compliment btw.

Alderin NTT4 months ago

Personally, I don't like the overlapping designs because they never
seem to fully close, whereas a large version of this one could be built
with tongue and grooves between the blades for a very solid closure.

Adding more blades should make the blades smaller, to lessen the width of the border. That said, I'm stuck on the math of how to make this happen beyond the 5 here. Maybe more blades could be worked out with compass and a lot of paper, but I'm not 100% sure it'll work.

That said, if you aren't minimizing the layers, and you keep 5 blades, you'd only need 1x the blade width outside of the doorway, so about 1 meter (Where the corners stop at 'open'). The actuation ring could be where the corners stop, such that the swing arms are tangent to the circle. It adds 2 layers to this design, but removes that 1m extra 'depth' around the door for you.

jwkooi4 months ago

Very nice project!

NTT (author)  jwkooi4 months ago

Thank you :o)

schaie4 months ago

just sayin, Carl bass didn't design this, http://boingboing.net/2010/06/25/chris-schaies-mechan.html wish he would give credit too.

NTT (author)  schaie4 months ago

Ah. I didn't know that.

Like you I do hate it when people don't reference things. Particularly when we're all in this for the same good cause.

quinn4 months ago

It's a really attractive and significant upgrade. I'm going to make one at Techshop this evening. Wonder how my landlord would feel about me installing it in my front door...

NTT (author)  quinn4 months ago

Ha ha ha! Do it :oD

Don't forget the 1mm Perspex if you're going to be flipping or holding it on its side ;o)

MercuryCrest4 months ago

Thank you for this. I had made the original design and found that somewhere, somehow, something was off and things didn't perfectly line up (though they were close).

Looking forward to giving this another shot!

NTT (author)  MercuryCrest4 months ago

You're welcome.

I know what you mean with things being ever so slightly off. I noticed a couple of things that weren't centred perfectly, so hopefully this new take will have addressed them.

If you spot an error give me a shout :o)

jolie


rimar20004 months ago

BRILLIANT, congratulations.