Friday, December 23, 2011

Simple optics: I'm still doing it wrong

I did some approximate calculations and picked the really nice (expensive) laser lenses I needed.

I drilled out some plates to mount them on since they were both super fucking small. A little super glue and they were on there perfectly without messing up the light-transmitting surfaces or even having to touch them with human hands.

Then I disassembled the laser gun and used little stand up clamps to hold them in approximately the right places.

And it totally didn't work. The light was more or less collimated but it was so out of focus it just kind of spread out on it's own. It is clearly not going to work this way. But I didn't know for a while why it wasn't working.

I noticed that the website I bought lenses from also sold duplets (just two lenses affixed to each other). I also noticed that these duplets, which I'd gotten one of in the scope and one in the original projector, seem to work far better than any other lens I have. But when I look at diagrams of how they bend the light it doesn't seem to be any different than any other lens.

So I did some root investigation. I bought some simple 5mW lasers and shined them through the duplets.

It seems like the real strength of the duplets to me is actually their tolerance for poor placement. When you shine a light through them at not quite 90 degrees and centered the lens on the far side just corrects the odd angles the lens on the near side made.

In the case of the laser, it came through clear even when I was off by a bit. Using a single lens or a lens duplet I placed myself it would always be skewed out of focus because my placement wasn't just-fucking-right.

By contrast the manufactured duplet always focused the laser on the other size like one would expect even when I did it at a bad angle or offset from center.

At least that's my theory. So I did some more approximations and bought a duplet that I think will be better for this than the ones I have.

Sunday, December 18, 2011

My table has 99 problems. None of them are related to women because it's a table.

For starters, I've got the main shelf structure together. A few problems I've run into:

I didn't consider that the welded-on shelves would get in the way of the rollers. They do. I noticed after I'd only put on a few of them. A little angle grinding solved the ones I had on there. For the others, I just had then stick out the back a bit instead. This caused them to block the cross bracing in some areas. More angle grinding and some hack-saw.

The shelf that slides up and down needs to be put on by sliding it underneath the shelf structure. Unfortunately each side of the shelf structure weighs about 90lbs. They're just within my limit to easily maneuver. I believe I'm too weak to safely tilt a constructed setup backward so I can put the movable shelves on. I also don't believe the cross bracing would survive this. The shelves must be put on and then the main structure assembled. That's a bitch.

The cross bracing is generally too weak for how much the structure as a whole weighs. There's nothing that keeps it from bowing out. It'll have to be replaced with cut angle iron.

I've mounted the motor on the moving shelf. It does run but it makes a terrible racket. I need to run it more and investigate what exactly is being so damn loud.

During some light stress testing I also had one of the pegs for the rollers just fall off. It looked the welds were bad. I took an old piece I'd done as a test before doing this one and took a hammer to the pegs. They all bent instead of broke off. From that experiment I concluded that this piece was done badly but the process in general was good. I re-welded all the pegs on the existing piece and attached a new one in place of the one that fell off.

I've mounted the winch on the top piece. This just sits across both shelves. There's nothing particularly wrong with it except that I had to make pieces that kept it from tipping over and I didn't make them long enough the first time because I wasn't thinking.

Saturday, December 3, 2011

The new workspace: Submitted plans to the city.

Google docs link to plans

There's a process called 'intake' in which the city reviews the plans with you waiting there so they can assure you have at least all the documents and basic data you need and they can reject you right away if you're totally effed it.

During our intake, the woman reviewing our plans actually brought over her manager just so he could marvel at how ridiculous it was.

The planning phase alone was about $15k-20k. The city's share of that for permits and reviews was around $7k. We'll just have to wait and see if our plans are accepted by the city. If so, construction will begin around April. I'll still need to give more information about interior before we'll have a quote on how much the whole thing will cost.

Monday, November 28, 2011

When simple solutions elude you... keep thinking simple till they don't

I've got a winch. Winches are great. They already take AC, they run in forward and reverse (it's probably just AC rectified into a DC motor), and they're even geared down.

But they only have a cable, so I assumed I'd have to build a good-and-complex threaded rod system because the cable would be either in the center and in the way or I'd have to split it with a complex pulley system to get it to pull on both sides of the table.

I failed to realize till this weekend that really it's acceptable to mount the cable in the front, as long as it doesn't block this specific shelf. It can block all the other shelves it wants, just not this one. And each shelf will probably only be 12" or so tall. So all I really need is some posts.

Given this simplification. I think I'm ready to buy steel for the final table. I'll also need to start thinking about the electronics. Or rather I should have already been thinking about the electronics and now I'm going to get around to that.

Thursday, November 24, 2011

Lasers: Trying to be more intelligent about it

People like the laser. It looks flashy, it's very easy to use, and I might even be willing to bring it to a combat situation. So how can I make it even more kick-ass? How can I set myself up for making even bigger and badder lasers? I'll have to do this one right, no more trial and error.

I'm going to buy lenses, not just salvage them. ThorLabs seems to have a good selection and they even have special coatings for the different frequencies of light you're using (~430nm in my case).

Of course, real nice laser lenses are expensive. I don't want to buy a $3k kit of all the possible lenses and then play more trial and error. For now, let's focus on getting the right lenses, we'll deal with getting them in the perfect position later.

A normal convex lens can take an expanding beam of light and columnate it. However, with the dimensions of beam that I'm dealing with I can't find a single lens that has a focal point closer than it's diameter, which is what I need if the beam is coming out of a 1" lens and hitting a point 1" away. The best I've got there is a 12mm focal length with a 9mm diameter lens.

Instead, I'll use a concave lens to make the angle of beam more acute. It should then expand out after the focal point more slowly such that I can then use a lens to columnate it.

We'll find out.

Sunday, November 20, 2011

ME: The shelf V1 is done.

Remember all those 3D pics of how the shelf will work? Well I've actually built it. I've got about 1mm tolerances on everything. Special shout out to my L-shaped ruler for helping me get all the angles straight. I'll also say the hardest part of any of this is getting things in just the right position before you weld them. Will have to get a bunch of additional clamps when the house is done.

Now I better go double check all the dimensions and record them so I don't forget. :)

I got a box!

You can't call it a gun till you have a pelican case for it.

Monday, November 14, 2011

Photon Blaster I by Fail Train Industrial Division

I've decided to rename it. It's now the Photon Blaster Version 1. Produced by the same people that brought you water cannons and the MA-10; Fail Train Industrial Division. Also, there are new pics of it courtesy of LYTFYRE

Sunday, November 13, 2011

Fully functioning laser pistol

24W of blue laser ass kicking. I've never run down the battery but it should run for a full 20 minutes on a battery charge. If you want one, I'll make you one for $2k.

Friday, November 11, 2011

Pistol grip for a laser

The laser is almost done. Like everything I build, it'll be a half-functioning shadow of what I imagined. But it is bright as fuck; you can feel the heat on the palm of your hand a meter away. I got the final focusing from a lens taken out of an old rifle scope.

The final step is putting a grip on it. Once again, I just have to say how much I love 3D printers. You dream that shit up and you can print it...

triggerX = 25;

triggerZ = 21;

triggerRad = 18/2;

module grip()







cylinder(h=115, r1=17, r2=26, center=true);






cube([(triggerRad+3)*2, (triggerRad+3)*2,26],center=true);































module printableGrip()








cube([70,65,5], center=true);
























cube([100,100,100], center=true);






Sunday, November 6, 2011

Welding 101: I have no idea what I'm doing

What the fuck is this thing

The Millermatic 211 is a MIG welder. You press the trigger on the gun and it simultaneously feeds wire, vents inert gas, and creates an arc that generates so much heat it melts up to 1/2" thick steel.

The device is actually pretty straightforward to setup: Plug it in. Take the electrical clamp and attach it to whatever you're welding. Put on a helmet and gloves. Turn on the gas. Turn the machine on. Get in position. Press the trigger and try not to be startled.

The wire is fed from a couple pound spool that you put in the side of the machine. It's got a bunch of equipment to auto-feed that spool. Even auto-feeding the first time up into the gun was easy.

The helmet is fairly advanced. It automatically darkens when it detects UV light. Both the sensitivity of the darkening and the opaqueness can be adjusted. It need batteries. One interesting note: Looking at the sun is also enough to set it off. I still get a bit of a sun-spot on my eyes if I stare at the sun through it.

The gas can is 75% argon and 25% CO2. I have no idea why this mixture. The main goal is getting something inert. Why not all CO2? Why not all argon? I forget how much the tank holds but I do know that when I first slapped the regulator on it the dial registered 2200 PSI. Every square inch of the inside of that tank is holding back 1 ton of pressure. It's probably pretty thick. Still, don't drop it. Since the gas and wire didn't come with the welder I picked it up at a local welding supply shop. I get the impression this is mostly what they ever sell. The other gear was notably over-priced.

The welder itself only has two dials. It has some sort of auto-feeding circuit that means you shouldn't even have to touch one of them. That would be the feed-rate. The other dial is the thickness of the material you're welding. I can only crank it up to 3/16" before I'm supposed to be using a 220 outlet.

How hard can it be...

Fumbling my way through it

Step 1: Don't forget the gas. For the first weld, the one that looks cratered, I forgot to turn on the gas. Aside from looking like shit it is actually weaker. I was able to pull the weld apart. The two below it that are smooth and shiny are actually correctly done. I think in both instances here I've got the power turned down too low, however.

I'd previously cut holes in the angle steel and proceeded to weld the bearings into place by putting a piece of angle steel and doing my best to keep them in place. The originally cut holes, however were not perfect fits, nor were the measurements. Combine that with my inability to place the bearings and I got a final product that essentially didn't work.

So I opted to use the power of the milling machine. I made a set of holders out of wood. Milling wood is both simple and fast. This will allow me to hold all the parts exactly in place while I make the welds. Once I've got spot welds on everything I can go back through and re-weld the hell out of all of it.

In the end I worry I didn't give enough tolerance. I noticed after I'd done all that welding that one of the holders was off a bit. I'll have to wait to get more skate bearings to find out.

I've also considered just replacing this whole ridiculous setup with actual manufactured bearings but that immediately jumps the cost up to about $300 for a set (at least when I order from the generally over-priced McMasterCarr). I'd like to see if I can do this for more like $40. I'm willing to take another shot or two at it even after this.

Sunday, October 30, 2011

Hacksaws: Fuck em

First time I used a hacksaw I was ecstatic. Before that, it didn't seem possible to cut materials that were stronger than wood. Materials like aluminum or plastic. Since then, I've had to use a hacksaw (without a vice) for jobs as rough as cutting 1/4" thick, 2" wide steel I-beams. That takes forever and it's a workout.

Metal band saws are equally revolutionary. For something that would have taken 15-30 minutes and been shitty, I now do in about 30 seconds and it's perfect. Look at that edge: It's an exact 90 degree angle, single cut, super crisp. You can barely even seethe saw lines. 30 seconds.

Friday, October 28, 2011

Touching a far away world

This is a welding table. It's put together with bolds. I don't know what the bolts are made out of by it's not steel. Perhaps chips of old people's bones.

And it was made by hand. I can tell because the maker stripped out one of those bolts putting it together. A machine would have just fucked it up and given some error. This dude packed nicely, still totally broken, with the bolt but missing the nut he stripped. I didn't even notice it was wrong till I tried to put it together.

I think it's cute in a way that this person is probably just as annoyed with the low quality of the bolts that strip all the time as the customers whose stuff doesn't work the first time. I hope that person doesn't sweat it; we'll find extra bolts and in the end it's the cheap as company cutting those corners.

It makes you wonder a lot about that person. A tiny connection across the global distribution void.

Saturday, October 22, 2011

Macroscopic engineering: Apartments come with 240V outlets

Two important points: #1. Apartments usually come with 240V outlets. #2. You probably don't need them.

Washer/dryer and ovens often require higher power and can come in 240V models. As a result, even residential places often come with high-power outlets. My apartment was build about two years ago and it has both a 30A and a 40A circuit in it.

Of course, light industrial machines don't seem to even need that. For instance the Bandsaw I just bought only takes 7A (vs the standard 120V 15A circuit). Similarly, the MIG welder I'm going to use goes up to 20A on 120V but will probably stay below the 15A limit if I keep it turned down (we'll see).

On the subject of light industrial equipment in your apartment, I've also moved the accelerator target to down the hall to make room for all that swanky new shit.

I'd like to also give a shout out to Hazard Factory's founder Rusty. I took their welding class as an intro to heavier metal working. In part I loved it for being very informative and helpful for actually learning welding. In part I loved it because Rusty is like the nicest guy ever. You look him up on facebook and every single picture is of him smiling. I'd like to be such a person.

Sunday, October 16, 2011

ME: Paper


Getting into the specifics of the design, paper and imagination was absolutely the fastest way to find basic flaws in construction. It's far faster than CAD or building it even if you're trying to make clean drawings.

Once the design is a bit more final, CAD seems like a solid choice again. This time, not using a bunch of exacting math or trying to model it all but instead just using the values you know you will and trying to get things close. I'll add more to this cad drawing as time goes on.

The problem I was solving

Lets imagine how the grabber will work. There's the threaded rod. On either side of the rod are bearings. On one end there's also a gear that the motor connects with to turn it. Sliding along the rod will be the actual grabber arm and it's electromagnet.

This poses already several questions:

#1. What keeps the grabber arm from just rotating as the rod does? We could give the arm bearings to slid along some flat surface. I think instead it's probably easiest to just connect it to the other arm. They're supposed to move in tangent anyways and the cables to power the electromagnets on either side will have to go to both of them anyways. Also, that's just a lot simpler than bearings, which are either a pain or expensive.

#2. Just how close to the user can the table get? Will the fetcher be able to bring the shelf from all the way stowed to right next to the user? Not really. So how closer? If the bearing is there, that's 1.5" and then the arm will actually have to extend over the gear, another bearing at the other end, and the length of the electromagnet. All that will be 4" at least. Now the table is 6.5" away from the user at a minimum.That's getting to be a bit awkward. We'll have to cut out any connection on the far end of the fetcher arms. Either side will extend out a bit but the center will only connect farther back. This also makes the threaded rods more convenient; we won't have to cut those and they only come in 24" while the plan for the table is to be 18" deep. Of course, given that we decided on having a cross piece in #1, we will have some offset. Probably just the width of the cross piece and the electromagnets themselves. 2" seems tolerable.