It's Made of Wood... Yup.

Earlier in 2013, I started designing a version of Chibikart. Athought I knew I wanted my vehicle to be substantially larger and more comfortable to ride, the final goals for the project were not set in stone at the time and continue to evade me. I'm going to keep this post short because the project is not complete and this is basically just a photo dump with some words in between.

...just like all of my other posts.

The t-slot extrusions, known to me as 80/20 (supposedly 80% of the strength of aluminum at 20% the weight) will serve as the frame for this build and hopefully be adequate for any future four-wheeled vehicles I may feel the need to create in the near future. Special nuts can be inserted into the slots and removed without harming the extrusions, making them ideal for builds that are somewhat fluid in nature when it comes to component placement.

Thanks to the help of Evan Lane, I was able to cut sprockets from 1/8" 6061 Al using the mill in the BU Tinker Lab. <-- BU students, please come do things here so you will enter the job world with real engineering experience!

Test run on foam insulation

We made a fancy jig to hold it.

Number of end mils broken doing this: zero.

Done! Chamfer was added to the edges later, I promise.

The sprocket spacers were cut next.

A few tapped holes later, we've got drive wheels!

There was a small (big) snafu with materials and I was on a deadline for a competition (that I completely misunderstood the criteria for) so I was forced to lasercut all of the pieces that I needed so I could show the judges a thing that looked like a go kart and not a $800 pile of nuts and bolts...and a frame.

Here's a picture of the rolling chassis plus the throttle pedal, which I was overly excited to use, so I put it on as soon as I could.

The front wheels line up - cute.

The brakes were next

Then came the motors and chain.

Special thanks to Abominable Snowman Steering Systems.

A few hours later (in which I did not take pictures) a fully functional kart was completed. Not pictured: the seat, (arrived a few days later) the correct battery, and the sensors+boards (too lazy to put on before aluminum parts get here).

Please note comically large steering wheel. 

Current home:

Anti-grav comes standard in jasontrollers.

For the record, I did ride the wooden kart down the hallways of 44 Cummington for a few feet, but the wooden parts, especially the uprights, were very unhappy and were sagging from the weight of my huge ass. Stay tuned for when aluminum parts are cut and we do garage testing, hopefully by the end of the summer!

Phone Case Versions 1-3

Last winter, I designed a phone case for fun. When I designed it, I envisioned it out of aluminum. This idea was quickly scrapped as I thought about the effects on signal strength and how it was very easy to 'hold the iPhone 4 wrong,' according to Steve Jobs. In the summer of 2012, BU got a MakerBot Replicator and I decided to give my design a shot. 

Original.

There happened to be black plastic in the machine, so the case was black. It was a pretty good first try. The major things I didn't like about it were how flimsy it was, and how it didn't hold on to the phone as well as I wanted. It could be pushed side to side over the grooves on the iPhone 4 very easily. Additionally, the buttons were a bit tough to reach, despite the little recessions in the case.

At the time of the pictures, I didn't have any 1/2" 4-40 screws on hand, so this is the best I have. The screws were filed down and a hex nut was put on the back to hold it in place. This idea was scrapped because the nuts kept falling off and also placed unnecessary strain on the very thin corners of the first iteration of the case.

The next iteration came in late November. I had been using the first version for about a month after my 'real' case bit the dust. Props to Speck though, that case lasted me a year and a half. This second version had several modifications. The first was that the buttons were SUPER easy to reach, and the second was that everything was thicker. I did print one back piece with hexagonal cutouts for nuts just to entertain the idea again, but it felt forced and didn't look that great, given that I wanted to keep the case as compact as possible.

 This time the plastic in the machine was not black, but red!

After using the case for a few weeks and completing finals for fall 2012, I realized that I hadn't got any gifts for most of my friends for their respective winter holidays. Like any clever, financially broke engineer, I printed them iPhone cases with a little bit of personalization to make it seem like I put some effort into their gifts. (Boy, did I fool them...) Unfortunately, several weeks later one of them reported a four foot drop onto a tile bathroom floor which spawned a crack in the top. This quickly propagated inward and the upper left joint came loose. Just today, the other friend sent me a picture of his mutilated phone case, which had suffered similar failures. I'll take this time to say that my 'V2' case is perfectly fine and has survived several drops, albeit not onto tile floors. 

Tile floor: 1
  Case V2: 0

Bear attack.

Regardless, this motivated me to design version 3, which made the top piece significantly thicker and changed the structure of the side on the front only. The left side now appears to be whole from the front, but has a chunk cut out so that fingers can easily reach buttons from the back without sacrificing structural integrity.

So there you have it. We'll see how this iteration fares in the real world and I'll update the post with changes. Side note: several people have suggested that I try to mill this out of a stronger material, such as polycarbonate. This sounds like a good idea and wouldn't be too difficult to do in theory. This might happen. Hmmm.

Noble Six Helmet

Wow, it's been a really long time since I've updated this, mostly because I've been busy recovering from an appendectomy and pretending to be musical. A few posts ago, I mentioned that I was making something for a friend's birthday. That thing was my short-lived adventure into the world of prop making. Basing my designs off of those from 405th.com, I created laser cuttable files for Noble Six's helmet, from Bungie's Halo: Reach. I replicate the pepakura build in AutoCAD and cut the shapes out of 110 lb cardstock. The designs ended up on 11 sheets of the stuff, and took about two hours to cut, including setup. I still have most of the ream of cardstock. As a joke, I printed an essay on it, but have found no other use for it.

Guided by the original files in Pepakura Designer, I made a few of the major pieces, and then gradually glued them all together. 

Note to those thinking about doing this: hot glue is strongly advised because of the quick set time and the ability to heat it up again if you make a mistake. Keep plenty of glue on hand (I went through about a dozen of the small sticks in the process) and give your glue gun a break every so often - the handle on mine got pretty hot after a while.

Next in the process was the fiberglass and bondo. I used fiberglass mat and resin on the inside for structural integrity (bonus: itchy fingers) and bondo on the outside to smooth out the fairly wrinkly paper, add some bulk where needed, and hide errors.

Fiberglass. Note to self: use cloth next time; mat sucks.

I just realized that I don't have a picture of the helmet after I sanded down the whole thing. Oops. Anyway, the next step was painting the thing. The order of coats are 2X black matte, 2X silver, 2X blue, and finally black on the back and the visor perimeter. Painters tape was used to section off different areas that didn't need to be painted after a certain point, such as the visor. Vaseline was applied in 'swaths' to imitate scratches from battle.

Second coat of black. Nice and thick... and drippy.

First coat of silver.......... right.

2X silver.

Blue (as per Ben's character in the game)

It's a lion.

"Done."

Bonus ALVIN.

So at this point you're probably thinking something along the lines of, 'That came out pretty well for his first shot at making a prop from a video game, but how the heck is he supposed to see out of the darn thing?'

I was thinking that too; I'm glad we're on the same page.

At The Saturday Thing sometime in the fall of 2012, I got around to trying to make a visor for the helmet. This was supposed to just be practice, but I sorta decided it wasn't worth the effort to do it again. I started out by cutting out the silver chunk and making a frame/jig that I would use to press the acrylic piece into place. I used a heat gun and a large PVC pipe to make a rough bend in the acrylic, pressed it into place with the jig, and glued it into place. Not perfect, but it'll do.

The visor-hole and rough cut/bend of the acrylic piece.

This took a long time.

"So thats our new number Six?"

So there you have it. I have another blank helmet in my garage that I built on a whim, thinking I would have the time to make another helmet. I may try to do something with it, or it may just sit indefinitely.

 I have a few more posts coming soon, mainly something about a phone case and some really tiny things. Happy reading!

MRT Alaska Trip - August 2012

After mentoring in the Engineering Design Workshop each day, I worked with the MIT Marine Robotics Team to prepare for a testing trip in Alaska. Over the course of June and July we prepared two gliders for testing in a pool and in open water. One of the gliders was about two and a half feet long and served as a proof-of-concept model and experimental platform for sensors such as GPS, pressure, and dive/rise indicators.

Tommy and Baby glider

The second glider was our main focus. At five feet long and 60 lbs operating weight (about 45 lbs without ballast), it was tons of fun to bring through TSA... twice. After an hour long private security scan and half a day of travel, everything and everyone made it to Ketchikan safely.

Bubble wrap + greenie

The people at Ketchikan Gateway Borough very kindly let us use their dive pool for testing almost every day during the trip. It was an excellent place to test because the pool was nearly empty at 8am and we could easily trim the glider, check for leaks, test sensors, and get great footage from a GoPro mounted on Tom's ROV at the same time.

And they had a slide two slides.

The team also helped with a program called SeaGlide, which introduced middle school students to the world of underwater vehicles and showed them how to make mini-gliders using water bottles and an arduino. The program was spearheaded by Robert Vieth who specializes in STEM outreach in Alaska. Several employees from the Carderock division of NAVSEA also helped with the program.

Cleaning up a few of the 3D printed parts with our fancy knives

We also toured SEAFAC, but weren't allowed to take pictures most of the time, probably for a good reason. The best I could do for photos were a few on the boat ride out and one in their machine shop.

Biggest lathe I've ever seen

Lastly, the highlight of the trip happened after we had been given a tour of the mariculture facility and were allowed to test our large glider after showing it to the kids in the SeaGlide program. Gary Freitag was kind enough to let us use his SeaBotix ROV to get footage of the glider in the ocean. It also had a manipulator arm that we could use to grab the glider in case the glider decided it didn't want to come back up. That didn't happen, but the first untethered run was pretty terrifying/awesome anyway.

And so we put the buoyancy engine on a timer, dropped the glider in the ocean, and waited. David was in a kayak and I was piloting the ROV and everyone else was useless. Just kidding, they helped feed the tether off of the 800' spool. 

Warning: the awesomeness of the story that follows is not accurately portrayed over the internet. I'm not even going to try.

- Glider put in water

- Glider floats, refuses to sink despite pleas of MRT

- Two washers zip tied to back of glider

- Glider is pretty darn close to perfectly trimmed

- Glider starts dive cycle

- Dive looks good

- People start to remember that there is no tether

- Excitement ensues

- David is alone outside because everyone is inside looking at the ROV screen

- 20' below surface

- 30' below surface - we reached our target depth for the trip!

- Glider still diving

- People start to freak out

- Tom tells Adrian, "DON'T LOSE THE GLIDER. STAY WITH IT"

- Adrian stays with the glider

- 43' below surface

- GLIDER STARTS TO PULL OUT OF DIVE

- GLIDER COMES BACK UP TO THE SURFACE

- EVERYONE IS GOING CRAZY

- WE DID IT! WE DID IT!

- WOOOOOOOOOO

A video of our most glorious moment, accompanied by appropriate music follows. A few notes: the FS at the bottom stands for Feet Seawater, and the CA stands for Camera Angle. This is how we got our depth reading for the glider.

After we pulled the glider out, we got to have some fun with the ROV. Ed ended up stabbing picking up a sea cucumber from 200' and brought it up. When it got to the surface, it was a bit floppy from the pressure change, but fortunately it didn't evacuate its bowels on us, as sea cucumbers are known to do.

warp speed

"It's what's for dinner"

After returning the sea cucumber to its home and packing up, we merrily feasted on land animals, as seen in the following picture.

Kodak moment