Poor Man's “Laser” Cutter

Zero Cost Dumpster Diving Solar Project

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Focus the sun as narrow and as hot as I can, using a Fresnel lens from a projection TV.
No new tech here. Just proving the tremendous power of the sun at zero cost.
Environmental Advantages: A zero energy tool that works in areas with no access to electricity, fuels, wind, or water power resources.

Attention 2015 Hackaday Prize Judges:

Please save yourself time, this entry has No video.

Thank you so much for your time all your hard work to make this community awesome!

Setbacks have stalled this project, but I will attempt to continue to try to burn things after the Hackaday Prize.

Other than major setbacks, problems and failure, things are great! I love everything at Hackaday, I had a lot of fun following the Hackaday Prize, and the smaller prizes I won were very encouraging.

Old Details:

The 2015Hackadayprize should be fair to everyone, so I hope to prove that lack of money should not stop a person from entering the contest. Maybe even igniting a sense of independence with financially challenged hackers worldwide, to overcome obstacles by taking advantage of their surroundings.

Broken Projection TV's Abound!
There are thousands of broken projection TV's hiding in peoples basements and garages, destined for land fills. I see adds for free ones online everyday. If the lenses (Fresnel lens screen) from all of them were converted and used for power instead of garbage, the energy would be immeasurable. I'm saving one now. What if everyone did?

Safety Issues: This project is as dangerous as giving a kid a magnifying glass in a dry field on a hot sunny day. I will take precautions and make mechanical shutters to control the light.

Quality Issues: Some lenses work better than others. I don't know how good the one I have is, but we will find out. (uninformative Fresnel Lens Qualities link on side. Not mine.)

Budget: $0 – Everything must be scavenged for free.

Motivation: To build a portable "HomelessHackerSpace" of tools made from free or dumpster bound materials.


  • Optimistic – Cut and weld metal at over 2000F (1093C)
  • Realistic – Cut and etch thin materials for artistic projects
  • Last resort – I make the worlds worst reflow oven ever.

Other tools to keep in mind while dumpster browsing: 3D printer, reflow oven, CNC router, oscilloscope, or anything coveted at the HackASpace.

  • 1 × Free Hitachi Ultrascan HD 43” projection TV Saved From Dumpster

  • Implementing The Teensy-LC

    frankstripod06/08/2015 at 17:53 0 comments

    I want to thank Hackaday for the Teesnsy-LC I won in the "We're Giving out 125 Teensy-LC Boards this Week", part of the $50K IN PLAY contest! Thank you! I am excited to use this FREESCALE based part!

    Implementing The Teensy-LC

    1. To track the sun, aligned photo transistors or solar cells will connect to the Teensy-LC, which will relay a motor to rotate the lens. I decided a one axis tracking system would be the easiest and cheapest for now, and I will deal with the disadvantages of having to setup the correct angle of the sun each day.

    2. To find the melting point of commonly found elements, as mentioned on, by setting up fuse type system, breaking a connection of the remotely connected Teensy-LC, to record temperature on an infrared thermometer.

    First common conductive elements to test:

    • Zinc 419 °C
    • Aluminum 659 °C
    • Copper 1083 °C
    • Cast Iron 1260 °C
    • Stainless Steel 1363 °C

    I want to set these up as wires in rows on a firebrick, at a safe distance.
    Also, if I can get the temperature high enough, I would also see if I could duplicate this sand conversion:

    3. Eventually I hope to find an alternative solar device, because of the underestimated power of the sun.

    I wanted a diagram, but being a little short on parts right now makes it difficult to nail down some of the details. I'm giving KiCad a try, so please excuse the mess:

  • Trying to Focus

    frankstripod06/03/2015 at 03:42 0 comments

    First Heat Test:

    My $10 Harbor Freight Multimeter just happens to have a temperature probe that I'm sure is good to +/-25C, so I taped it to the back of an old metal PC cover and we are good to go for some in apartment testing before the wife gets home. Boring video alert!

    I used my vertical blinds as shutters for instant light control. Turning the knob either way makes an almost instant change on the meter.

    Focusing the slit:

    I was able to get the size briefly down to 80 x 3mm. You cannot see the point in the video or pictures, even with the exposure turned down. It was a lot harder than I thought. I was constantly adjusting the position of everything, but couldn't get to a sweet spot. The key to me succeeding will be to find light weight and semi portable materials that will be ridged enough for near precision focusing.

    Maxed out at 90C! (194F... OK, more like chickened out.)

    Also the light was not fully direct so it was distorted towards the carpet, so I'm hopeful I can get much higher.


  • The Hitachi 43FDX01B Teardown

    frankstripod06/02/2015 at 08:37 4 comments

    This was too easy. There were no hidden screws, no hidden tabs snapping off, no tricky disassembly order, no blood and no cursing at all, so by definition its more like a take-apart than a teardown.

    Please Help! If you can, help me figure out what other projects I could make out of these parts! I will be happy to take more pictures, like of the large caps. I would like to keep it all, but will eventually have to reduce the size :(

    Preliminary Focal Point Information:

    - Screen: 43" diagonal, about 34.5" x 26"

    About 109cm diagnal, 87cm x 66cm

    - Focal point 26" from the lens. (66cm)

    Closer than I imagined, so smoke on the lens will be a bigger problem.

    - Common vertical slit shaped point

    About 4" high and 0.5" wide in the middle (about 10x1cm).

    I was hoping for a small spot, even though it was a long shot, but this is much better than an unfocused blob some get.

    Lets start with the back.

    The front screen lens assembly is held on inside by four metal bars screwed into the front plastic frame.

    Flash lens reflection.

    Back cover mirror.

    Very trapezoidal.

    The mirror is nice and thick, but the backing is a thin coating. You can see a little flaking at the edge, but you cant see the hazy streaks from age in these pictures.

    Someone spilled coffee in from the front (we are calling it coffee).

    Most people would imagine a high tech inside, but most of the craftsmanship in this thing is in the woodworking!

    100 years worth of dust. I'm sure glad I always remember to teardown outside. I only found one dead bug.

    Make that 200 years worth.

    Lots of shielded boxes all over.

    Wires and plenty of connectors.


    Many side boards and lots of caps and resistors

    Tube board.

    Original handmade wood strain relief.

    Lots of these furry things.

    Turns out they are heat sinks! 04686A?

    IC's everywhere.

    Front speaker panel, With traces of "coffee".

    Front panel velcro.

    Engineer 1: "Just two pieces of velcro for the front, really?"

    Engineer 2: "Don't worry. It will hold for 30 years."

    Yep, it still held for 30 years. Unfortunately the velcro glue backing specs had to be lowered for cost...

    Two full range speakers :|

    The adjustable side of the three projector lenses.

    Underneath are the three projector guns with circuit boards and large metal shields with holes.

    Closer view.

    Holly resistor Batman! Now they can put three million SMT resistors on one real smaller than that gold band! Some of the caps are big also.

    I finally found the reset button! Its right below that 90,000V line in the foreground. How convenient.

    The four metal bars holding the screen are off and two layers of the screen are both taped together and are also glued together, about 0.25" in from all the edges. A razor blade carefully slid around all sides between the layers separated the two pieces below.

    The clear protector looking front plastic (UV?) was hard to photograph.

    A closer inspection shows another layer glued to the lens I want. It looks like a diffuser. Once started with a razor, it pealed clean off the lens.

    Diffusing layer separated.

    With the other two layers gone, I mounted the single lens back into the frame. Fits tight :)

    Above you can already see it magnifying the carpet and a kind of circular square section of sky in the reflection. I was hoping to use this frame, but it is much more flexible than I expected.

    The focus test (26") was quickly disrupted by rain and a quick clean up before the wife comes home to a mess and kills me. It only focuses in direct light, so weather permitting, maybe I can get some pictures of the focused slit tomorrow.

  • Missed the LightBlue Bean Givaway

    frankstripod05/07/2015 at 08:39 0 comments

    I totally missed the LightBlue Bean board givaway this week :(

    I could have used it to control some remote X, Y movements like this:

    And upload designs to it from online files on an Android phone.

  • First Plans

    frankstripod03/29/2015 at 11:22 0 comments

    Here is the first item literally saved from a dumpster:
    Hitachi Ultrascan HD 43" projection TV model 43FDX01B.

    Like most big screen projection tech from the '80's and '90's, every time you moved them there was a large risk of damaging the alignment. In this one the red lens is not only out of front panel adjustable alignment, but the red vertical scan wiggles, so I'm guessing there is a broken part in the red projector.

    Peeling off and hanging on by a thread is the original packing sticker protecting the like new looking rear input panel.

    First design plans:

    I thought it would be cool if I could reverse the direction of light and use the outer shell as the project case.

    Lets skip that step, and the visit from the fire department, and move on to the next design.

View all 5 project logs

Enjoy this project?



Fabio Balzano wrote 06/28/2015 at 08:57 point

Congratulations! Great work!

  Are you sure? yes | no

frankstripod wrote 06/28/2015 at 09:35 point

Nothing great yet, until something burns :)

  Are you sure? yes | no

Fabio Balzano wrote 06/28/2015 at 08:55 point

Congratulations! Great work!

  Are you sure? yes | no

davedarko wrote 05/14/2015 at 21:01 point

so the teensy icon guy wins an teensy LC :) congratulations! 

  Are you sure? yes | no

frankstripod wrote 05/14/2015 at 22:02 point

Thank you! I am so happy! The icon looks kind of desperate, but at least you know I had it for a long time :)

  Are you sure? yes | no

davedarko wrote 05/15/2015 at 14:05 point

I am happy for you, too! I hereby confirm that you had the Teensy Icon for a long time :) have fun with it - I still have some dev kit boards I have to check out my self.

  Are you sure? yes | no

frankstripod wrote 04/28/2015 at 04:12 point

@Stefan-Xp @esot.eric.wazhung, @haydn jones, Thank you. I have been busy and it took me a while to figure it out; I was actually watching that Solar Sand Converter video at the same time you were commenting here, but I didn't know it. I haven't given up on this project yet, thanks for hanging around. Now I want to melt some sand and glass :)

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Sophi Kravitz wrote 05/13/2015 at 20:54 point

melting sand and glass!!! yesssss

  Are you sure? yes | no

Eric Hertz wrote 03/31/2015 at 04:10 point

Hah! Nice... use the case/alignment-stuff that's already there! Brilliant!

  Are you sure? yes | no

frankstripod wrote 03/31/2015 at 04:31 point

Yes, in its original "brilliant" design, the light should perfectly reflect back through the projector lenses setting the PC board on fire. I'm surprised more of these have not burst into flames. I bet there is a protective layer behind the screen we will see real soon. Its hard for me to get to the disassembly right now for several reasons (one being taking up the center of the living room without the wife killing me. This project will require some buttering up for sure!)

  Are you sure? yes | no

Eric Hertz wrote 03/31/2015 at 05:25 point

Hah! Yeah... space is an issue! Wives... well, I hear they don't get too happy about things like this, but the forgiving ones are keepers!

I came across a broken one (projection TV, not wife), briefly... There were several plastic sheets at the screen, one I think was nothing more than a surface for the light to diffuse on... That probably prevents fires ;)

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Leonard wrote 03/30/2015 at 11:07 point

You might want to place an extra horizontal glass plate to keep the smoke coming off your project from the mirror, or your mirror will be dusty soon.

  Are you sure? yes | no

frankstripod wrote 03/30/2015 at 20:32 point

Excellent point! Smoke will be a big problem. I was hoping to eliminate mirrors with a strait through design (dictated by the focal point), once I get this thing apart. I like the glass idea as a lens protector. Do you know anything about heat absorption in glass?

  Are you sure? yes | no

Leonard wrote 03/30/2015 at 23:14 point

It depends :) In this case it depends on the type of glass you use. Light, as in, visible light will not pose a serious threat on a thin pane of clear glass when it's about heat, anything that does absorb heat does though, and could kill your glass pane. Making sure your glass is clean is a must. Logically, the more dirt (smoke -> carbon) on your glass pane, the more it absorbs heat. There's also reflection to take into account. If you focus a beam of sunlight, the more lenses/glass/transparent material you use to guide your beam, the more gets reflected, and basically is lost to heat. 

Then there is the absorption of heat by glass itself, something about the infrared in the spectrum being either reflected or absorbed, you may want to read on that, or you may lose significant energy just but adding a layer of glass.

Instead of a glass layer ( =energy loss anyhow), you could place some fans that blow or suck away the smoke.

I hope you can pull this off, it certainly would be fun :) Post some pictures when you're at it. 

Last thought is, the first collection of sunlight can be done with a reflective hollow mirror, perhaps something like a parabolic dish. Just my two cents.

Make sure you are safe :)

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frankstripod wrote 03/31/2015 at 04:13 point

A fan is a great idea, but no way to run one yet. Also thinking of a chimney. More pictures soon, promise. I appreciate the help. Thank you :)

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Martin wrote 03/25/2016 at 08:28 point


I don't think a chimney works - you don't want to accumulate so much heat. Whats the problem with a fan? You could run it from solar cells, if your project shall be able to work without external electricity.

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davedarko wrote 03/29/2015 at 14:17 point

Sounds awesome :) Now I want to see this in action - burning stuff!

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Stefan-Xp wrote 03/29/2015 at 15:03 point

m2 ;-) A while ago I seen a propdingnagy lens which melted layered sand to create vases :) Looking forward for your achivements! Take care, safety first ;)

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frankstripod wrote 03/29/2015 at 21:56 point

Safety first indeed! Thank you! I would appreciate any suggestions on finding free lenses, or how to make one. Setting up focal distance soon :)

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Stefan-Xp wrote 04/20/2015 at 15:17 point

There is it :)

Thanks to @haydn jones!

Also interessting: #Solar Sand Converter - Solving the sand problem :)

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Eric Hertz wrote 04/20/2015 at 15:27 point

Excellent proof-of-concept.

And, if just laser-cutting, probably not as much need for as much heat. Maybe a single TV's Fresnel lens is enough :)

I wonder about the size of the light projected on the sand... Am guessing it's due to the Fresnel-equivalent of spherical-aberration, but that the actual focal-point is tremendously brighter/hotter (as well as smaller).

Also makes me curious about e.g. "laser" 3d-printing of the resin-vat-sort... rather'n resin (or sand, here)... wonder what'd happen with powdered-(black)-plastic... a good use for shredding all those old floppy disks :)

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haydn jones wrote 04/20/2015 at 15:28 point


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davedarko wrote 04/20/2015 at 15:31 point


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