Wednesday, December 11, 2013

VDSKart: TIG Welding Aluminum Frame

I've been meaning to build an electric vehicle a bit more exciting than my Electric Orbit Wheels. And by a bit more exciting, I mean ridiculous acceleration, drifting, and driving around MIT campus at odd hours of the night. It's about time I built something that I could bring along and race Ben's trike in the Stata basement. I've accumulated a few very nice parts from the recently deceased club in N51, Vehicle Design Summit (VDS). Most of this kart will be assembled from parts I scrounged from VDS: hence the name VDSKart.

Due to the ridiculous size of the solar car axial flux motor that Ben generously donated, this vehicle is going to be a full sized racing go-kart, a slight deviation from MITER's smaller electric vehicles. It's probably going to weigh upwards of 150 lbs and won't fit through doorways, but it will go really really fast and accelerate like a sports car. I'm using aluminum round tubing for the frame to decrease weight, to learn how to weld aluminum, and because it's available.

After looking at many different designs for racing go-karts, I came up with this frame.

More on practice welds and crufted parts after the break. 

Monday, November 4, 2013

Shortest Path to MITERS

I finally got around to precisely measuring the different EC to MITERS routes on Google Earth. I wasn't sure how the path through the Swapfest parking lot compared to the others, but this confirms its about the same distance. As for the numbers:

White = 693 meters (the absolute shortest distance to MITERS from EC)
Red w/shortcut = 848 m (includes the sidewalk currently blocked by construction on building 35)
Red w/o shortcut = 856 m
Blue = 858 m
Purple = 858 m
Orange = 964 m

So really, the shortest path is past Building 13 and along Mass Ave with the diagonal sidewalk towards the intersection of Mass Ave. and Vassar (which only saves 10 meters (+/- measurement error)). 

The red path is also probably the fastest because of the straight stretch past Building 13. However, I've gotten a little bored of the same route, and have now switched to the purple path (even though it's 2-10 meters longer). 

Just for kicks, here's the same route placed over MIT the year after I was born.

Saturday, October 5, 2013

Earth in the Foreground: Building the Pan/Tilt Time-lapse Platform

Before heading up to Alaska to film the Sun up above the Arctic Circle, I made a device to slowly move the camera in pitch and yaw using some of Joseph's stepper motors and scrap metal around CSAIL. 

Electric Stater System Troubleshooting Part 2: Yes, Small Wires Limit Current

After reading and talking with some friends, I realized my earlier conclusion that the starter motor had a short is not the case. Because it turned slightly, the current is providing some torque. Therefore, it isn't shorted. If the starter motor did have a short, it would not have turned at all when I hooked the battery straight to the motor.

With that, I went out, found some containers that looked like they would do the job, and drained the engine oil and the coolant system. (Afterwards, I learned my lesson on how to find appropriate hazardous waste containers and dispose of them properly).

Repairing a 42" Plasma LG TV

A couple days after the end of 2.00 Gokart there was a huge supply of electric vehicle goodies. Unfortunately, I was at the final performance of Roadkill Buffet, "MIT's premier improv comedy troupe", while most of the good cruft got crufted. Some of the earlier crufters got their hands on a 42" plasma LG TV and tried fixing it on the spot (thinking it was just a blown fuse). By the time I got there, they were giving up on it. So, being the naive and ambitious person I am, I decided to carry it back to EC and learn a bit about how plasma televisions work. Thankfully Ed Moriarty was there cleaning out the 2.007 Underwater Vehicle section's materials, and was able to drive the TV over to East Campus. After some debugging and replacing some parts, I ended up with a pretty big monitor. 

Monday, September 2, 2013

Krepes: A New Type of Billiards Game

Raku Watari and I used to play a lot of Billiards and Cut-Throat at ADPhi when we were room-mates freshman year. We would try improving our techniques by hitting with spin and trying to predict where the ball would end up to be in line for the second shot. After awhile, we got tired of the same game and decided to "invent" a new one. We present Krepes:


Why Krepes, you ask? Because we were eating Infinite Crepes at one of ADPhi's Rush events while we thought it up (and also, because it has nothing to do with the game--similar to Puzzles). 


The game of Krepes can be played with any number of people, but 2-5 players is preferred. There is no foul for hitting a stripe or a solid directly with the cue ball (with exceptions for the 8-ball). There are two ways to hit the 8-ball and win Krepes. First, a player can use any striped ball to hit the 8-ball in a pocket--a combination shot. Second, a player can hit the 8-ball directly into a pocket IFF all the solid balls are off the table. The solid balls must be hit in order--similar to a game of Nine Ball. A player can pocket a striped ball to continue his/her turn, but decreases his/her chance at winning instantaneously by hitting the 8-ball in with a striped ball. This encourages strategy and multiple possible shots. If a player hits a solid ball in order, it increases his/her chances to hit the 8-ball in successfully, but does the same for his/her opponent. If all the striped balls are gone, the only way to win is to first go through the solid balls. 

  1. The cue ball can hit any ball legally (with exceptions for the 8-ball). 
  2. A player wins by pocketing the 8-ball. 
  3. A player can pocket the 8-ball by first transferring the kinetic energy of the cue ball through a striped ball. 
  4. A player can pocket the 8-ball by hitting it with the cue ball directly, iff there are no solid balls on the table. 
  5. All solid balls must be hit in order (1-7). Pocketing a solid ball out of order may result in a foul. 

Fouls: Resulting in Loss of Turn
  1. Player hits solid ball of correct order and pockets a solid ball of incorrect order.

Fouls: Resulting in a Scratch
  1. Player pockets a solid ball of incorrect order. 

Placing the Cue Ball after a Scratch:

A player, who follows after the previous player scratched, can place the cue ball anywhere on the table. However, he/she cannot pocket the 8-ball with a striped ball to win with his/her chosen cue ball position. 

The General Rules of Pocket Billiards apply except when directly contradicted by these rules. If you have any suggestions or ideas for improving the rules, please comment below. Enjoy!

Thursday, August 1, 2013

Electric Starter System Troubleshooting Part 1: Learning How to Drain Engine Oil Among Other Things

I've been reading through the manual to troubleshoot why the starter switch might be causing the relay to go nuts. The ZX600RC1 manual referred to a Base Manual for going through the starter motor removal in detail (which thankfully was updated on this forum 12 days ago).

After reading through the base manual, I found some possible scenarios which may be causing the symptoms it's having. A winding on the starter motor might be open (having infinite resistance) which would make it very difficult for the current to make the starter motor turn. Also, if there's a short between the commutator and the shaft, that would indicate that the armature has a short and would cause weird things to happen to the starter circuit relay. (The starter circuit relay is different than the starter relay, because it's behind the starter lockout switch. The starter lockout switch ensures that the vehicle is in neutral and the clutch is engaged - the clutch handle is out - in order to prevent the bike from being started in gear. The starter relay is what directly controls current to the starter motor).

This picture will help explain:

Tuesday, July 30, 2013

Motorbycle: A Bigger Electric Vehicle... Or So I Thought

After the Electric Orbit Wheels and the extremely fun nights/early mornings in the Stata Parking Garage with Ben's Trike, I started thinking about a bigger, faster electric vehicle. The Electric Orbit Wheels are great for short commutes around MIT, but not for midnight garaging. 

I started playing with the idea of returning to my childhood and making a small motorcycle (not a pocket bike, but a small motorcycle similar to Mars's). (I also wanted to make my own Continuously Variable Transmission (CVT) to help with drag racing in the garage.) I've actually been riding motorcycles for most of my life, I've just never taken one apart or built my own. It's time for that to change.

Sunday, July 14, 2013

MIT Museum: Electric Orbit Wheel Demonstrations

After seeing the Electric Orbit Wheels at Tech Fair 2013, the Director of Education and Public Programs at the MIT Museum, Brindha Muniappan, invited me to the Play Day at the MIT Museum on April 17th to do a demonstration. I didn't hesitate to accept. Since then, I've been demonstrating the orbit wheels and the most recent GlowBoard every other weekend at the museum. It reminds me of the good old FIRST days when my team, 3705 Porhtal, would take our robot around to various schools around the state of Alaska and teach robotics. 

For more pictures...

Thursday, June 20, 2013

Earth in the Foreground: How I Managed a Research Trip to Alaska

Flying into a Beautiful, Sunny, Hot Fairbanks
This project requires a good introduction of Ed Moriarty. I first met Ed at a summer camp at the University of Alaska Fairbanks (UAF). At ASRA (Alaska Summer Research Academy), Ed was everywhere. He would stop by every module checking in on whatever cool things we were up to. He was also very involved in and taught the Underwater ROV and Extreme Photography Modules for a few years. Ed has done a bunch of cool things in Alaska to spread awareness and get kids excited/inspired about science and technology. 

Recently, we were talking about ASRA, and he had mentioned that he's been dreaming about getting a 24 hour time-lapse video of the sun above the Arctic Circle in Alaska for quite a long time. So, I looked into it, received a grant from the MIT's CAMIT Arts Grants, and started building a device to take a moving time lapse. A couple weeks passed, and I hopped on a plane to Fairbanks, 181 miles below Finger Mountain and our decided video location. Not only is Fairbanks a good location for setting up equipment, but it's also the location of my family's house. Here's the story of my adventures researching back home.

Friday, May 31, 2013

Servo Actuated Gauge: Part 2

I finished up the wireless servo actuated air pressure gauge. The last things remaining were to finish the transmitter, and make a small transmitter box to house the transmitter PCB with a dial and markings corresponding to the servo actuated gauge. 

Monday, May 27, 2013

RC Servo Actuated Air Pressure Gauge

As part of my Undergraduate Research Opportunity (UROP) at the Computer Science and Artificial Intelligence Laboratory at MIT, I took apart an air pressure gauge and added a servo to remotely move the needle. I hacked the parts used in the air pressure gauge to make a four-bar-linkage with a servo I crufted from the remains of Charles' 2.00GoKart class. I'm not sure if I can reveal the intentions of doing this for secrecy of the CSAIL project, so I better be safe and not mention it.

Monday, May 6, 2013

GlowBoard: A Welded Steel Mini-Skateboard

Inspired by Ben's PocketBoard, I decided to make a small skateboard in order to scavenge free food faster. It all started when my roommate crufted an old skateboard from his fraternity. I went on Ebay and found some awesome glow-in-the-dark 70x51 mm skateboard wheels. I wanted to make the deck such that I could maximize the visibility of the wheels. I recently learned how to MIG and TIG weld (thanks to Mars) and after finding some steel rings in MITERS' scrap metal I decided to practice my welding technique (before welding together my future electric motorcycle). I made a wire-frame deck with supporting steel rods underneath and the negative piece of a water jetted steel wrench for the truck plates. 

For more on the build process...

Sunday, April 21, 2013

Early Morning Waxing and Waning Photography

By "Early Morning" I mean 0300 to 0600. Eric, a really awesome programmer on my hall, and I didn't feel like sleeping. Instead, we started carving the large pieces of wax another one of our hall members crufted from Reuse awhile back. Eric had a nice camera and some color filters of various shades. We played around with them and actually got some really interesting pictures. Here is a slideshow of our doodles.

Some of these photos would make a great desktop background!

First All-Nighter at MITERS: Casting the Urethane Wheel

I've been procrastinating the molding of the orbit wheel in favor of machining for too long now. I need at least 24 hours for the mold to set. Starting three days before TechFair.

Tightly Packed Electronics and Machined Housing

After my motors, motor controllers, and HobbyKing radio transmitter and reciever came in the mail from a long and expressed journey, I could start on the electronics. I decided not to cram it all inside with the ring gear, because I may potentially get sprinkling aluminum flakes as the bearings etch away the water jetted surface. This change of plans required more machined aluminum, which I could do on the MITERS mill.  

Cruft Shelf

I found a really nice piece of plywood on hall, and my closet was overflowing with closet stuff and cruft. So I decided to make shelf exclusively for crufty things. Also, since I have a loft, I have a bunch of places to attach things. Therefore, I can make the most efficient use of the space in my small room (it is actually the smallest room on hall and the only "double"). 

Click to read about the very short build:

3D Printed Urethane Mold and Ring Gear

The ring gear was the main reason I decided to make my own wheel. I couldn't find any wheels without hubs that also had a ring gear inside. So I designed a wheel rim with a bunch of water jetted aluminum rings (one being the ring gear). The ring gear was the most stubborn of the bunch. It really tested my dedication to this project. There were a few times that I ran out of ideas on how to make it. But I persisted. I was probably doing it completely wrong, but I came up with a solution that worked using Autodesk's gear generator.

Tuesday, April 16, 2013

Changing a "Rusty 'Ole" East Campus Faucet

The sink had a terrible drain ever since my roommate was assigned the room (partly the reason we chose the other single to move into and build a double loft). It also didn't look very aesthetically pleasing, especially for something that spits out "clean" water. These unpleasant traits weren't enough for me to fix the sink before, because we turned the room into a guest room (used primarily for sleeping). However, when I knew my Mom was going to use the guest room during Spring Break, I had more of an incentive to fix it.

Faucet leaks around the side when running
Sink basin is full of dirt and gunk
Does not drain properly (water sits in the sink for hours)
Not usable

Sunday, March 31, 2013

Making the Battery "Packs"

Time to make a battery pack. A very oddly shaped battery pack. Before I did any soldering, I had a good discussion with Shane and read a bit about how Charles made his battery packs for his various electric vehicles. I also sketched up a method for how I can assemble the batteries and then fold them after soldering the ribbon cables. Whiteboards help.

Water Jetting!!!

My GRT (Graduate Resident Tutor), Kyle, on my floor, 5W (aka QED), works at CSAIL, has waterjet access, and knows OMAX.

OMAX is the software that converts an Autodesk or a SolidWorks file into a coordinate language the waterjet can use to cut out the part. The first time I went waterjetting with Kyle, we had to format all the parts in OMAX (a couple hours of work at the computer in the waterjet room). Later that night, I got the software to be able to finish all the formatting for future water jet trips.

I used OMAX Layout to set the quality of the cut (how slow the water jet cuts along the edges), set the cutting path (this is extremely important, because if the water jet cuts on the wrong side or in the wrong order, parts will be messed up).

Saturday, March 30, 2013

CADing: Preparing for Water Jet

Since I didn't really elaborate on the CADing aspect of the laser cut acrylic orbit wheel prototype in the previous post, here's the story behind it:

I've been CADing with Autodesk Inventor since 2008 when we built little puzzle cubes in my Introduction to Engineering and Robotics at Lathrop High School. Many people at MIT use SolidWorks, but I can't give up that nice little cube in the top right corner of Autodesk. Eager to start my new project, I decided to go with Autodesk. Maybe I will do my next project in SolidWorks.

I'm spending a lot of time refining my CAD files before printing them on the water jet. I can't use the free scrap stock in MITERS' pile of metal, because there aren't any water jetable 1/4 thick 8 inch squares. By "water jetable" I mean that there must be enough metal on the edges of the part in order to clamp it down to the machine. Therefore, I want to make the Autodesk files as detailed as possible to avoid wasting the nice 8" wide aluminum stock I got from McMaster.

Picking out Motors and Batteries

As this is my very first electric vehicle and first big project at MIT, I didn't know what type of motor would work best. I talked with Ben, an experienced tinkerer, and he recommended a motor with low kv and pointed me towards HobbyKing. (The lower the Kv the more torque the motor can produce).

Chibikart's motors are Turnigy 5065-256Kv Brushless Outrunner Motor and have a can diameter of 49 mm. After looking on HobbyKing's website for a while I found a similar motor to Chibikart's. I ended up ordering three Turnigy 4250-350Kv Brushless Outrunner Motors with a can diameter of 42 mm. I left my browser on the HobbyKing page for awhile and they gave me a discount!

I'm thinking after I gear it for torque with the ring gear, the motor will be able to move a decent sized human at a decent rate (faster than orbit wheels without a motor that is).

Now that I got my motor picked out, I started thinking about batteries.

I decided to use the big A123 28650 Systems Lithium Nanophosphate cells. They seem to be a popular and common choice at MITERS.

I spent a lot of time researching what type of wheel I could use. I couldn't find many hubless wheels that were big enough to put my foot through (and even if I did they didn't have a ring gear inside). So I decided to build my own ring gear rim and pour the urethane rubber around it in a 3D printed cast.

And since I was planning on making my own wheel, I wanted to make "no crush wheels" so I could have some sort of shock absorption in the wheel itself.

In order to make these, I bought some molding urethane from Smooth-On. They sell 80A shore (a measure of how hard the material is) Urethane Rubber, which is very similar to the hardness of skateboard wheels, in little trial sizes and gallon sizes. I decided to purchase a trial size to test out if it would work for my purpose.

I'm planning on building one orbit wheel at a time (rather than simultaneously) to test how well the no crush wheel idea works. I could have some problems with getting the stiffness of the shock absorption just perfect. Otherwise, if it is too flimsy it will be like riding a flat tire, and if it's to stiff it won't be any different than a regular wheel. This way, I can incorporate any changes and improvements into the second wheel.

Monday, February 18, 2013

Pull-Up Bar

This project was mainly inspired by Raku (and the fact that I found a perfectly sized steel tube in the MITERS stock pile). Though getting more exercise has been a thought of mine for a while. During robot season in High School, I wouldn't really play sports or exercise on a daily bases. Now at MIT, it's constantly "robot season" with MITERS and all. Having access to a convenient pull-up bar may help with my lack of exercise (Broomball helps a bit too :).

More on the building process after the break:

Sunday, February 17, 2013

Loft and Painting


When Raku, my roomate, and I opened the door to our room, it was plain white. White is boring. So we bought some "Mango Orange" paint from Dickson Brothers and True Value (we bought a small tester then a big gallon). Both of those hardware stores are near the MIT/Harvard Square area. I found some Gaffer Tape around the Edgerton Center, and Ed Moriarty, a truly awesome and inspiring person who works at MIT's Edgerton Center, found some paper I could use for preventing paint blobs. We then proceeded to tape all the places we didn't want to get orange paint on. (I really wish I had pictures of this process. That was back when I wasn't a blogger).

So, I need to back up a second. Raku and I signed up to be roommates, but we were assigned two different singles. During Rush, we had heard the idea that two people moved into one room and then turned the second room into a movie theater/building/everything/awesome room. Raku and I decided to do something similar. We planned to paint one room orange, the other blue, and then put portals on the doors.

We slept in our other single while we were in the process of painting. We basically went the first month at MIT without completely unpacking our suitcases.

After putting two coats of paint on, it turned out really nice.


We both wanted to build a loft. We managed to scrap some nice 2x4 and 4x4 boards by helping disassemble the fun rides in East Campus's courtyard. Every Rush and CPW, East Campus builds awesome contraptions (like roller coasters and ride-able double pendulums).

(Skipping all the design process) Here's the final product. If you want to read about the rest, click the read more link below the image.

Completed Loft :)

Thursday, February 14, 2013

Lego Tetrix Nuts and Bolts Sorter

In my senior year of High School, I took a class on Engineering Design and Development (EDD) with Project Lead The Way (I think it's funny that their acronym has more syllables than their name). In the class, we went through the ten steps of design and development to ensure that our product met its design specifications in the time allotted and had a market for the problem it solved.

Mr. Ehnert, Lathrop High School's engineering department Instructor and LHS FIRST Robotics club Coach, has 15 FIRST Tech Challenge (FTC) teams that he takes to the Alaska State tournament every year. (That's a lot of nuts and bolts).

I decided to make a project that I could leave with Lathrop as a sort of "going away" present for Mr. Ehnert.   That's when the idea of a "Magic Sorter" was born. The purpose of this Tetrix Nut/Bolt Sorter was to decrease the amount of time spent on sorting robot parts. By doing so, it would also increase the time for productive robot building. In the class, I made 3D printed and laser cut models to solve the sorting problem and complete it's purpose. However, the "Magic Sorter" didn't work as well as I envisioned. So, I worked on improving it over the summer.

I started playing around with mechanisms in my Lego box. And, well I decided to build the whole thing out of Legos. I didn't have a "blog" back then, and I didn't take any pictures. The pictures below are from when I came back during Winter Break after my first semester at MIT.

"Magic Sorter"

Hopper and Laser Sorting Section

Here's the Tetrix Sorter in action! I took a bunch of short clips when I came home for Winter Break. I finally got around to compiling them into a "pretty" video. Enjoy!

That last clip is at a weird angle. I wish I could take a better video to get the whole thing functioning, but I'm currently about 5238 kilometers away from it (thanks to Wolfram for that statistic). 

Saturday, January 12, 2013

Laser Cut Orbit Wheel Frame

I have finally pulled my orbit wheel design out of my computer. This was a fun quick build for my first time "T" nutting. This was also my first time using StartLab's laser cutter, which is very similar to my high school's laser cutter. Now I have a good prototype to show at my first check-in meeting with TechFair.

Here's a cool video of the laser cutter doing its magic! I especially like how the flame underneath makes the entire transparent acrylic sheet glow. 

I had some trouble getting the scrap pieces out, because the laser cutter didn't cut completely through. I ended up breaking the skinniest part on the green orbit wheel frame trying to push the scraps out. I fixed it with some very thin super glue. I also increased the power of the laser by 5% to ensure that it cuts all the way through. Other than that, cutting went well.

Cut Orbit Wheel Pieces

I used some 10-32 screws I found in MITERS screw drawer. I ended up not using every t-nut I designed for, because it wasn't necessary for structural support. I included my hand in the picture to give a feel for how big the orbit wheel is. It is actually quite small, which will allow it to be transportable. The plan is to be able to strap these on my back pack.

My crocs fit in well so I can lift up my foot and the orbit wheel doesn't fall off. This will help with going over curbs so the orbit wheels won't shift positions while I continue to move.