making fresnel lenses with makerbot

[fra...@maui.net]

A couple of questions for you gurus out there:

 1> Can makerbot make transparent objects? I don't know much about the resins you are using...
 2> How clean/clear would such objects be?
 3> Has anyone tried making fresnel lenses?

I'm trying to break the price barrier on solar fiber-optic skylighting.  Believe it or not, it costs
about $100k to get a decent in-home system.  I believe it could be done for under $1000...

Regards

Dave Scruton
fra...@maui.net

[Darcy Whyte]

It might be able to make the spacers or holders for chunks of mirror? Or glass?

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[McCrum]

As much as I love this idea and am certainly willing to throw any
knowledge your way, this is a tough one.

Let's star with what fiber optics are: Staggeringly expensive because
they are very tiny, very pure rods bundled together with a flexible
sleeve. The flexibility is important because you're bending light
around corners. The end where it meets the light source is then
cleaned and polished in laboratory conditions and housed in a metal
sleeve that is then placed precisely in an illuminator to capture as
much light from the source that is being reflected to a certain point.

1 - Yes
2 - As far as I have seen, somewhat, but not really very. Mostly
because the extruder is sending out a tiny strand of plastic and
building up layers. This is mostly precise, but think of the clarity
of a stack of clear straws bundled together.
3 - Someone may have, but this is also somewhat difficult because of
the precision involved. A Fresnel lens was originally created with
the same focal properties of a traditional curved lens but essentially
has a series of cuts like a ziggurat made in the flat side and is then
squished to make it flatter, thus eliminating the build up of heat
from the source which, at the time, destroyed larger curved lenses.
My point being that you can probably source some less expensive
existing lenses that would work as well but aren't Fresnels. This
will be a lot easier than making your own.

Offhand, where are you trying to get light from and how far are you
looking to send it? Could you consider a periscope-type device with
mirrors instead? Fiber optic's staggeringly purity will make building
it difficult and even with factory-grade stuff you probably end up
losing about 30% of the original source through various ways. But I'm
intrigued and am certainly willing to do what I can, let's talk about
what the problem is though, there may be a better solution than fiber.

Jeff
mcc...@hotmail.com

[Angelo Tartanian]

Hey Dave,

The Makerbot is an FDM (fused deposition modeling) printer, which means it is basically a fancy computer controlled glue gun. Officially supported materials are ABS (the kind of plastic used for legos) and PLA (a corn based plastic). Because of the way that the material is put down I'm not sure you could get the detail that you would need for a functional fresnel lens, also, it's not the clearest stuff in the world, even when it's very thin. It might be possible to use a print as a negative for making a resin cast... I don't know of anyone that has tried to create a lens on a makerbot, but a quick search on thingiverse.com (makerbots model/design sharing site) didn't turn up anything. Darcy's suggestion above seems like another reasonable way to use a makerbot to create a fresnel. Good luck! Let us know if you learn anything about making lenses with 3D printers!

-Angelo

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Angelo Tartanian
Skype SN: angelo.tartanian
cell: (908) 892-6453
angelo.t...@gmail.com

[astrida]

You might be able to laser etch something to get a fresnel lens
effect. I'm thinking etching or cutting clear acrylic might work.

[Angelo Tartanian]

http://hackaday.com/2012/01/09/diy-fresnel-reflector/

On Thu, Apr 26, 2012 at 10:15 AM, astrida <vast...@gmail.com> wrote:

You might be able to laser etch something to get a fresnel lens
effect.  I'm thinking etching or cutting clear acrylic might work.

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[McCrum]

This sounds more like a diffusing item than a focusing item. A lens
bends and redirects the light to focus it to a smaller point. The
clear acrylic would need to be shaped to focus it, so I like the idea
of using a printer for a mold to pour something in but I don't think
the ABS would stand up well to anything that would be heated (glass)
so possibly some clear epoxy of sorts to make a lens. I'm just not
sure it would optically be enough to bend the light.

[McCrum]

I like this, but it's a reflector to bounce light back at a point and
reflect sunlight back towards the source, essentially making it do a
180 degree turn. Dave is looking to focus the light from the sun to a
point and keep it going in the same direction.

On Apr 26, 10:23 am, Angelo Tartanian <chunkymidgetmon...@gmail.com>
wrote:
> http://hackaday.com/2012/01/09/diy-fresnel-reflector/

>
> On Thu, Apr 26, 2012 at 10:15 AM, astrida <vastr...@gmail.com> wrote:
> > You might be able to laser etch something to get a fresnel lens
> > effect.  I'm thinking etching or cutting clear acrylic might work.
>
> > --
> > You received this message because you are subscribed to the Google Groups
> > "NYCResistor:Microcontrollers" group.
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>
> --
> Angelo Tartanian
> Skype SN: angelo.tartanian
> cell: (908) 892-6453

> angelo.tartan...@gmail.com

[eva lansberry]

Found a nice lens in a dumpster of TV repair shop. From an early flat screen TV

Best,

 

Eva Lansberry

LEED AP BD+C 

  

[Ted Hayes | Limina.Studio]

Yeah, but couldn't it still be used for that purpose? The reflector faces the sun and the fiber optics are placed at the focal point and routed to wherever they need to go... A bit janky, but cheaper, I guess.

-t3db0t

[Lou Klepner]

As for the optical fiber end of things, you might be better off with plastic instead of glass. Its cheaper, has a bigger diameter, and its easier to tool. 

[McCrum]

Well, you're taking light from the sun, reflecting it off a surface
and back towards the sun where it would presumably meet the "in"
portion of the optic. This "solar cooker" works because you're
heating up the sun side as well as the dark side.

In terms of reflectance, NASA gets about 95% from their mirrors. A
white ceiling gets about 80%. So even with the best technology on
earth, we're already down 5%, expect good mirrors to get, say 90%.
But let's say that we're redirecting an additional 20% of surface area
to that point, through reflection we're now getting 108% (.9*120) of
just plain sunlight.

Now, we're also taking an opaque object (the fiber head) and putting
it in the middle of the point where the sun is, casting a shadow on
the reflector, causing even more loss. At that point, we're pretty
close to the original 100% of just pointing it at the sun. in the
first place but with a lot more work and more things to fail at
various times. Once you start adding in reflectance multipliers light
intensity starts to drop really fast.

On Apr 26, 11:35 am, "Ted Hayes | Limina.Studio"

[Pablo Martinez]

Forgive my ignorance, but how many fresnel lenses do you need?

http://www.ebay.com/itm/56-FRESNEL-LENS-SOLAR-OVEN-WATER-HEATER-FRAMED-linear-/170814188711?pt=LH_DefaultDomain_0&hash=item27c551aca7#ht_4418wt_1078 

http://www.ebay.com/itm/49-FRESNEL-LENS-Solar-Oven-Hot-Water-Linear-Fresnel-/180858525448?pt=LH_DefaultDomain_0&hash=item2a1c021708#ht_5611wt_1078 

Those are 56" and 49" fresnel lenses respectively, for less than $120 shipped. Would those do?

On Wed, Apr 25, 2012 at 5:51 PM, <fra...@maui.net> wrote:

[Ted Hayes | Limina.Studio]

Sure, of course. I'm just thinking out loud from a cost point of view; in the interest of making something really cheap that still gets some of the job done ;)

_t3db0t

[fra...@maui.net]

Hi all...

I've been looking at Himawari's solar light collectors as an example:

http://www.himawari-net.co.jp/e_page-index01.html

they look like a small version of the keck telescope with
12 lens-shaped collectors and one solar sensor mounted on a
2d gimbal.

It's probable they are using glass lenses to focus the
sunlight. Does the sunlight need to be focused to a point
at the fiber's entry point, or does it need to be all
delivered as close to parallel as possible?

I've been pricing fibers and 1mm fibers look affordable.
Don't know about surface polishing; i've assumed that
glass when heated just right forms a spherical shape on
the end. I was going to go with that at the start...

As far as delivery, I'd try a simple fresnel circular lens
maybe one inch across...

Tell me what I'm doing wrong; please...
--- mcc...@hotmail.com wrote:

On Apr 25, 5:51 pm, <frac...@maui.net> wrote:
> A couple of questions for you gurus out there:
>  1> Can makerbot make transparent objects? I don't know much about the resins you are using...
>  2> How clean/clear would such objects be?
>  3> Has anyone tried making fresnel lenses?
> I'm trying to break the price barrier on solar fiber-optic skylighting.  Believe it or not, it costs
> about $100k to get a decent in-home system.  I believe it could be done for under $1000...
> Regards
> Dave Scruton
> fra...@maui.net

[fra...@maui.net]

If it could be proven functional as transparent acrylic,
then glass could be substituted later as the design matured.
That way it's the cheapest it can be during the design phase.
There's nothing worse than machining glass and having it
be all wrong ..


--- limina...@gmail.com wrote:

>>>>> --
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>>

>>>> --
>>>> Angelo Tartanian
>>>> Skype SN: angelo.tartanian
>>>> cell: (908) 892-6453
>>>> angelo.tartan...@gmail.com
>>

[fra...@maui.net]

I'm Ok with a reflector too. It just needs to be small and
mountable on a gimbal for solar tracking...

[Darcy Whyte]

but index of refraction is different so it's hard to test with different materials for optics.

[fra...@maui.net]

Can the makerbot be used to produce a mirrored surface?

--- mcc...@hotmail.com wrote:

From: McCrum <mcc...@hotmail.com>
To: "NYCResistor:Microcontrollers" <nycresistormi...@googlegroups.com>

[Darcy Whyte]

I wouldn't think it would work very well. 

I think it would be better for making the mounts for mirrors, reflectors or lenses.

[Pablo Martinez]

Fair enough. Interesting project. Perhaps look into how fresnel lenses are manufactured. Looks to me like carved/routed polycarbonate, or glass. If that's the case, you need to get some plans, and a CNC machine.It's a nice project, just filter out that UV light.  :P

[McCrum]

Well, that had been my point. You could not make something and
achieve the same amount of light.

On Apr 26, 1:25 pm, "Ted Hayes | Limina.Studio"

[McCrum]

I'll have a look at the details of this when I get a chance this
evening, but my question was also about what kind of light levels are
you trying to get in the room at the end? 1mm is a pretty small
amount to start with and 1" at the other end doesn't sound like it's
going to illuminate a room. How many of these are you planning to
have in a space?

> > frac...@maui.net

[fra...@maui.net]

excellent point which i didn't think about.
is the index of refraction consistent across the many layers laid down?
has anyone considered this?

Dave Scruton


--- da...@siteware.com wrote:

From: Darcy Whyte <da...@siteware.com>
To: nycresistormi...@googlegroups.com
Subject: Re: [NYCR:Microcontrollers] making fresnel lenses with makerbot
Date: Thu, 26 Apr 2012 13:42:34 -0400

but index of refraction is different so it's hard to test with different materials for optics.

On Thu, Apr 26, 2012 at 1:41 PM, <fra...@maui.net> wrote:

If it could be proven functional as transparent acrylic,
then glass could be substituted later as the design matured.
That way it's the cheapest it can be during the design phase.
There's nothing worse than machining glass and having it
be all wrong ..


--- limina...@gmail.com wrote:

From: "Ted Hayes | Limina.Studio" <limina...@gmail.com>
To: nycresistormi...@googlegroups.com

>>>>> --
>>>>> You received this message because you are subscribed to the Google Groups
>>>>> "NYCResistor:Microcontrollers" group.
>>>>> To post to this group, send email to
>>>>> nycresistormi...@googlegroups.com.
>>>>> To unsubscribe from this group, send email to
>>>>> nycresistormicrocon...@googlegroups.com.

>>>>> For more options, visit this group at
>>>>> http://groups.google.com/group/nycresistormicrocontrollers?hl=en.
>>
>>>> --
>>>> Angelo Tartanian
>>>> Skype SN: angelo.tartanian
>>>> cell: (908) 892-6453
>>>> angelo.tartan...@gmail.com
>>

[fra...@maui.net]

Darcy's right. I'm tossing out the fresnel lens idea for now;
I'll try to just design the framework and lens holders in plastic.
The project is for an indoor plant illumination system.

[fra...@maui.net]

Light loss isn't as important as just getting the light through,
IMHO; at that point it's all about efficiency.

--- mcc...@hotmail.com wrote:

From: McCrum <mcc...@hotmail.com>
To: "NYCResistor:Microcontrollers" <nycresistormi...@googlegroups.com>
Subject: [NYCR:Microcontrollers] Re: making fresnel lenses with makerbot

Date: Thu, 26 Apr 2012 11:19:45 -0700 (PDT)

Well, that had been my point. You could not make something and
achieve the same amount of light.

On Apr 26, 1:25 pm, "Ted Hayes | Limina.Studio"

> >>>>> --
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>

> >>>> --
> >>>> Angelo Tartanian
> >>>> Skype SN: angelo.tartanian
> >>>> cell: (908) 892-6453
> >>>> angelo.tartan...@gmail.com
>

[McCrum]

Light loss is the same as efficiency. If you have a system that is
80% efficient, you have a 20% light loss factor. My point with the
reflector system is that if you're building a reflector and ending up
with 100% of the original light going in to the head, doesn't it make
just as much sense to save yourself the time, energy, and cost of
making the reflector to just point the head at the sun itself and get
that same 100%?

Having finally gotten a chance to read their stuff on their site, it
appears that they have six individual 1mm cables bundled as one
terminal, which then is run through the building to provide about 500
lux at 6 meters from their fixture head. Given the sun typically puts
out about 100,000 lux and traditional fiber optic losses, it's
actually really good for a system like this. That said, if you're
putting together your own system, why limit yourself to six 1mm
fibers? How about starting with something larger to get more light
into the room in the end?

How much light for how long are required by your plants?

[Darcy Whyte]

By concentrating all the light in one place you get a higher temperature and can do more useful work such as roast a marshmallow. 

--
Darcy Whyte

Inventor, Artist, da...@siteware.com

[Ted Hayes | Limina.Studio]

Hey all, this Saturday, Kitchen Table Coders is doing a workshop on networked interfaces using Arduino & Node.js:

http://kitchentable31.eventbrite.com/

—t3db0t

[Kaliptus]

awesome!

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Email: Kalipt...@gmail.com
Cell#: (917) 653-8905
http://kaliptus.com
http://kaliptus.blogspot.com/

[Benjamin]

We, at HackerspaceCLT are having some success creating molds or reprap parts, and creating copies in a clear resin;

Not sure of the UV stability of the materials however.

On Wednesday, April 25, 2012 5:51:36 PM UTC-4, fra...@maui.net wrote:

A couple of questions for you gurus out there:

 1> Can makerbot make transparent objects? I don't know much about the resins you are using...
 2> How clean/clear would such objects be?
 3> Has anyone tried making fresnel lenses?

I'm trying to break the price barrier on solar fiber-optic skylighting.  Believe it or not, it costs
about $100k to get a decent in-home system.  I believe it could be done for under $1000...

Regards

Dave Scruton

fra...@maui.net