Archives for category: Engineering
Here’s a few parts I made for Oriole Park at Camden Yards. I headed down to the stadium today to test the fit, and it went perfectly. All 9000 padded seats between the dugouts behind home plate use two of these. It’s a self adjusting bracket to hold the seats to the rest of the chair. Since each seat is angled differently to face the field, a simple bracket doesn’t do the job. This bracket has a rotating ball in a socket to accommodate for any angle. I unfortunately don’t get to sell them the entire 18,000 sets of parts that they use for the whole lot because these are just replacements for when the originals break, but it’s still a nice order and pretty need to add them to my client list! The black one is the original, mine is the all white set. The company who made these originally got bought by a different stadium seating company, and they no longer offer these parts. They don’t break too often, but when they do, the seat is unusable, so it’s always good to have a few on hand.
 My white 3d printed ones next to the black originals

These three parts are the original pieces.

This is the 3d printed nylon part. The central ball rotates freely to any angle.

You can see the metal bars that stick out from the arm rest.
The ball part fits right on the metal bar, and adjusts itself to the angle as needed.
I tested the screw hole placement in their repair shop on a newly refinished padded seat. They replace the vinyl on these all the time.

It works! Installed in section 30 row 29 seat 11

Here’s a great article shapeways put up about it:

I decided to flex my maker muscles and create this prop replica three different ways. If you haven’t seen the movie yet, you should. This is the card that Princess Leia gives to R2-D2 in the very beginning of Star Wars: A New Hope that contains the plans to the Death Star. We finally get a close-up of it in Rogue One: A Star Wars Story, and it’s one of those things I just had to have.

The first one I made is currently up for auction, and half of the total will be sent to Make A Wish Foundation in Carrie Fisher’s memory.

Going from least expensive equipment required to most, I’ve documented the steps taken to create this replica. The first just uses a laser cutter, painters tape, sand paper, spray paint, and acrylic welder.

First, I sanded a sheet of white acrylic with 220 grit to get the paint to stick nicely. Then I covered a large area with blue painters tape, and laser-cut the profile, as well as several concentric circles.
I carefully removed the tape, leaving thin blue areas to mask off sections I didn’t want the paint to get to

Spray-painted a nice coat with gold paint. The taped off area between the circles block the paint like a stencil.

Once the paint dried, I peeled off the tape.

I was careful not to scratch the paint when peeling out the thin areas.

I then cut a piece of black acrylic and used fast set acrylic welder to bond it to the bottom, for a finished piece! I made two this way, slightly modifying the base, and one without sanding the acrylic, so it’s glossier.
The second method uses the laser cutter, a vinyl cutter, and acrylic welder. 
We’re using gold vinyl directly instead of using paint. I found measurements for the width of the slot that the R2 builders are using and adjusted the width of my prop for this method to fit in there. I also wasn’t happy with the length and arc at the top so I modified those dimensions. FinallyI tweaked the black bar so you don’t see any white on the side of the black part.

The brushed gold vinyl is still on its way to me, but I like the vinyl better than paint already. Plus it’s easier to do so that’ll keep the cost down. I messed up the placement of the vinyl on this prototype… It’s too high. When I make more of them, I’ll use registration marks to be sure to line things up correctly.  As in the first step, two layers of black acrylic are welded to the bottom. The shape is a little bit different this time to hide the white edge inside the black acrylic.

This way was easier and provided a cleaner look. I think the new vinyl coming in just after New Years will look even better. It has a brushed gold look to it, which I think will look better.

The third way is a whole lot of steps. I routed out the copper PCB, transferred a vinyl sticker to the board to act as a mask, etched away all the exposed copped, remove the vinyl mask, nickel plated the copper, and then gold plated the nickel.

Gluing down the copper board to a base layer

Cutting out the shape of the board with the router

Cutting vinyl for etching mask

Use transfer tape to move the vinyl to the copper board (sorry it’s not centered! Just a prototype)

Pouring homemade Cupric Acid etching solution to eat away the exposed copper. This is cheaper and more environmentally friendly than the traditional Ferric Chloride method.

Waiting waiting waiting…

Refreshing the solution with more oxygen by adding some hydrogen peroxide 

[[I’ll update this eventually with the plating steps.]]

Final version went through a few revisions, but is made of aluminum as the card base, a white layer, and then copper plated with nickel for the trace lines and gold for the central circles. With the details that were view-able in the blue-ray, we got a lot more information.

I’ve got these final version ones up in my etsy shop if you’d like one.

My girlfriend and I recently got in to rock climbing. If you’ve never been before, basically there’s a rope tied to the climbers harness which then runs up to the top of the wall, and then back down to a device attached to the second person’s harness. The second person is called the belayer, and it is his or her job to hold the rope with the assistance of the belay device, catching the climber if they fall. They also have to keep their eyes on the climber as they go up the wall.

Keeping your head tilted back to keep your eyes on the climber can end up quite uncomfortable. Some clever folks have invented these devices that use prisms to reflect your vision upwards, but allowing you to keep your head straight forward, easing the stress on your neck. The problem is these glasses cost 80 to 100 bucks! It’s more expensive than any single piece of climbing gear I’ve gotten so far.

My friend Nancy showed me these funky laptop/reading glasses that deflect your vision downward for use when laying on your back and reading in bed, or watching TV without sitting up. At the time I thought they were just funny things with no real use, but were neat to play with. Look in the window on the right in the right picture below and you can see how they “bend” your vision downward.


I ordered a set from China from Amazon for $5 and figured I’d be able to modify them to work for climbing.  Turns out I was right and it just took a couple minutes!

Here’s how to do it:

You’ll need a few things to get started.
A flat screwdriver or something small and flat to pry with. I used a lockpick I had laying around.
You’ll also need some glue. I used gap-filling gel control locktite.
You’ll also need a rotary tool like a Dremel. I used the cutting wheel on my Foredom flex-shaft tool.
 And finally, get yourself a cheap one of these for $5.08 shipped or $15 if you want them quicker.

I’ve ordered a $15 pair and this $5 pair. The $5 ones seem to be the exact same as the $15 ones, so might as well go with the cheapest you can find if you don’t mind waiting an extra week or two.

Pry apart the little rectangles inside the frames. They’re just press-fit in place and pop out pretty easily with the right tool.

Once you pop the rectangles out, the prisms can slide out smoothly.
Now for the tricky part. You’ve got to cut or saw the triangular shield piece off while leaving some material behind. Without removing it, you won’t be able to see upwards through it, so it has to be removed, but you need to leave some of it in place to reattach the prisms. 

Use a saw or rotary tool to cut the shield part off, leaving triangles, one on each side of each opening, four triangles total. Remove the top black piece and discard.

Use a drop of glue on each triangle to secure the prism in place.

Position the prisms in place, upside down from how they previously were.

Conversion complete!

Bought a copper clad circuit board from radio shack

I spraypainted it black.

Then I drew the shapes I wanted in autocad, and prepared the file for the laser cutter.  I did a test in the corner first.  The laser blasts away the black spraypaint, exposing the copper

mixed 2 parts hcl with 1 part h2o2, which forms a copper eating solution.  

The liquid turns green as it eats away the copper

After lasercutting, A small amount of residue was still on the board, and caused it to not etch away in the solution, so I rubbed a tiny amount of acetone to wash off the residue, but it smudged the mask so the results were subpar. I had no idea acetone was that effective on paint. It smudged instantly, but I thought I’d be able to quickly rub and wipe.

 acetone washes away the remaining paint

second attempt:

Better, but still not good enough. Using the rubbing alcohol to clean up the residue was a big improvement over the acetone swipe.   I’m looking for straight lines, 90ยบ corners, and round circles.  I’m not sure if maybe I’m not letting the paint dry enough, or maybe this method isn’t accurate enough for what I’m doing.

Hi there, and welcome! 

I just launched my Kickstarter campaign for GlassKap, a lens cover and other fun hardware accessories for Google Glass. GlassKap is a plastic, perfectly formed lens cover for Google Glass. GlassKap provides a visual cue to your friends and those around you that you are neither recording them nor snapping pictures with the blink of an eye. The Kaps come in vibrant, noticeable colors that put people at ease. While the Kap is snapped, no recording can happen. If you’re coming here from the New York Times article, here is a link to the campaign. Check out the video, and get involved!