The Long Awaited

I fully realize that I have not posted anything new (despite there being absolutely awesome things happening!) since Fall 2012. That is because I was busy. However, I did that thing called graduating and now have oodles of time to back-blog all the good stuff.

Everyone awaits they day they graduate. I've been hearing it from my peers for the past 4 months, accompanied by tears of joy, tears of sadness, and senioritis. The part of graduating I was anticipating the most was actually commencement ceremony. Not because of the symbolism when walking across the stage, or moving the tassel, but because there were large groups of people present. Time to do something awesome in my last hurrah: Decorate my graduation cap.

The original plan was to illuminate a piece of acrylic from the side using RGB LED strips. An arduino nano or equivalent uProcessor would control the transitions between the colors. All of this would be powered by one of my numerous 3s lithium polymer batteries. However, I was lazy with the parts ordering. So here is the final instructable on how to make this guy.

Parts:

• graduation cap
• 1 meter long LED strip
• 3s lipoly battery
• polycarbonate U-channel (mcmaster 1753K61)
• a switch (min 1/4 W)
• wire and misc plugs

Step 1: Design the acrylic cutout
I designed it using SolidWorks. Began with the diamond shape and then extruded-cut the letters. The logo was generated from importing an image and projecting it onto the background. Using the Spline tools I could trace the more complex geometry.

The material selected was acyrlic. This was because it had excellent optical properties and could be laser cut using the machines at the Georgia Tech Invention Studio. 

Step 2: Cut chamfers into the polycarbonate at the bend points
The most important thing to remember about this is to have enough allowance in the bend. I'm not going to discuss k-factors here, but cut away some extra material to allow the corners to meet without stressing the sides of the U. Do not just remove material along the theoretical permissible lines.

Step 3: Apply LED strip to the inside of the U-channel
The LED strip I linked too earlier has an adhesive back. This made it much easier to stick to the inside of the channel. Also, I believe the width of this strip is 6mm. Should interface perfectly with the mcmaster part number I also linked earlier.

Step 4: Bind the ends of the U-channel to encapsulate the acrylic cutout

Step 5: Attach to grad cap (hobbyking brand superglue!)
The acyrlic plate actually levitates within the constraints of the polycarb U-channel. If I wanted to reuse these materials, I could unfurl the polycarb channel and simply take everything out...

Step 6: Solder wires and connectors
I recommend adding connectors on both ends of the power switch. One plug will be for your battery, the other allows you to take the cap off without having to extract all your electronic guts. I may update this step to include my wiring harness.

Step 7: Graduate!

The cap was well received by everyone (except the fire marshall). As a result, I received lots of air time that afternoon.

From the GT camera crew there:

... and  the Atlanta Journal Constitution.

What a way to cap off the end of a four year adventure. Thank you friends for all the wonderful experiences. I dedicate this work to remember all of you.

Some Responses from non-GT folk:


":OOOOOOOOOOOOOOOO
i want to sex you in the most non gay fashino possible
so one of us has to be in cosplay"


lol...

The next step for me is the legendary MIT!

InVenture Prize: Final Run!

This week is the finals round of the InVenture Prize!




Not much to say here except...

... COME TO THE EVENT! It will be held at the Ferst Center for the Arts on the Georgia Tech campus, at 6:30. Come early, get better seating.

Here's a Facebook event:
http://www.facebook.com/event.php?eid=167796909938807#!/event.php?eid=167796909938807

I am told it will be streamed live here:
http://www.gpb.org/inventure

Come please!

Survey: Self-Balancing Electric Skateboard

Please help my team win the Inventure Prize by filling out this short survey. I promise it won't hurt!

The next prototype. Notice no hand controls, unexposed electronics, and simple design.

-22" long, 12" wide, 6" tall (wheel height)
-Weight reduced all metal frame for strength and durability while light enough to carry.
-Pneumatic wheels allow the user to silently and gently cruise over bumps and obstacles.
-Lithium Polymer batteries allow over an hour of run time with minimal weight
-Runs about 9 mph
-Rider Sense safety features prevent accidental injuries to self and others
-Customize your ride with a variety of interchangeable decks!

If you're completely unsure about prices, here are some related products:

$550- EMAD Electric Skateboard	$160- Razor E200 Electric Scooter
$190- Sector 9 Longboard	$6200- Segway i2 Personal Transporter
$300- Altered Wombat Electric Skateboard	$760- Altered Drop Electric Skateboard

Hardboard: Death Metal \m/

So it turns out the springs won't cut it. I decided to haul the board with me one rainy day and ride it between classes. Pretty poor idea. First of all, the wide tire surface and the slickness of running water caused the board to hydroplane down some fairly steep slopes. The worst part was knowing it would happen. As I coasted down the hills of Georgia Tech, the board would oscillate violently. Turns out the springs were too soft and too responsive so a small semblance of a turn would soon be amplified to full extensions in a short period of time. I bailed off several times.

I put the board away for a few weeks and tacked other important things in the mean time. The finished Longpack for example.


I am a big fan of the blue shrink wrap. What I thought was really cool was how I could actually use the range on top of my stove to heat an area. It made me feel much safer than running a lithium battery under a flame.



The boards are in! Xo placed the order with Advanced Circuits and we received them as a strip of boards. I took a few of them with me to the Invention Studio one morning and cut them to size with the dremel tool.


The slot was also made through the ground plane to facilitate the edge of the nunchuk.


I also added some hall effect sensors to the hub motors. Three per hub motor, 120 degree spacing, attached to the tooth.



I'm not adventurous enough to try the flipped tooth method that Charles uses, although it would be much more convenient as I found out in the process.

Enough of that. THIS BOARD NEEDS TO HAPPEN NOW! I grabbed the deck and started prototyping resistive methods.

This plastic clip made from UHMW proved to be promising. The issue is that the truck angle is about 45 degrees, which means there is a 1 to 1 ratio between the person's movement and the trucks movement. With a person placing their weight on the edge of the deck, this means the resistive plug needs to exert 200-300 pounds of force without breaking or permanently deforming. Not an easy task.

Fortunately, these little guys did the trick.




These are also made from UHMW, but are taller and have additional bolt holes for more support. The older versions (also in the picture) have only two bolt holes, which twisted and widened after continual use.


What's left? Well next up is to solder the components to the boards. This should happen on Monday. My goal is to have this riding on Tuesday. How sweet would that be if I took the motor board to my meeting with Dr. Forest? =D

Pretty Pictures

Some models I designed and rendered for a friend of mine.




Not so bad for a freehand drawing. I didn't have anything to go off of except this picture.

Spirit of Building: Return to HÄRDBÖRD

Not sure if I ever started a post about the electric skateboard, but here goes.

Introducing Project HÄRDBÖRD: for lack of better name. Feel free to give suggestions; maybe something about the look of the board will inspire you.

Anyway, this is a greater attempt at personal mobility devices since my electric bike. This project features:

• Custom Waterjet frame
• 2 brushless wheelmotors with hall effect sensors
• A123 cells for power
• on board charging system for ease
• (possibly) custom brushless controllers
• wireless control via custom nunchuck controllers

I drew up the plans together with my friend Xo and together we are going to tackle this ordeal. Here is a Render.



Basically, the user holds the nunchuck controller and uses the sticks for proportional control to the motors. Ideally, I would like the buttons to do something (like underglow) but that increases power consumption for Rx and Tx.

Yesterday my parents drove up to visit and brought up the parts that Big Blue Saw had made way back when.

Turned out pretty well if I say so myself. Some minor errors [missing an extrusion and hole spacing is off], but I have been in contact with Simon ever since trying to get them straightened out.

I need to buy tools soon so I can begin putting this together. Each of the boards have a small amount of flex which both good and bad. Most longboards have flex as a natural shock absorber and turning aid but since Xo and I have electronics underneath, it would be ideal to reduce the amount of bend.




























Build On \m/

Return of the Blogger

Been busy no doubt, but I have returned for the time being. I just put out two blogs for GT Admissions, so why not my personal blog?

Recent items: Second Semester has begun. I am a Sophomore of 32 hours right now, with a current 18 credit hour workload. If everything goes for my summer plan in Baltimore, I will be a junior before the next year begins.

Robots: Competed and succeeded at GCRS over the winter break. First place for Cake, and non-placables for DDT and P150. Even if they had failed epically, it was still entertaining as hell :)

Speaking of FIRST, I love my Bacon



more later, I am lazy.

Another Day at the Lathe...

More parts done. Nuff said.

Coming Along

Alright guys, today I got my B16 gearmotors (still looking for spares however!). More importantly, I got another "round" at the lathe after the Battlebots meeting tonight. Result:










I got the front set of wheels done! I used the new design over the old one because it actually accommodated for the width of the rubber ring. I would have finished the rear set, but a guy from another organization needed the lathe for legitimate work so I'll probably go back tomorrow.










Meanwhile, I have enough parts to give a general layout. Donald and I had the same expression: That is waaaay small for a beetleweight.

Baker's Mistake

Alright guys, I made my first fail part (a few days ago). This was supposed to be one of the wheels I discussed earlier today, but more of a practice than anything. I'm still pretty noobish on the lathe.










First mistake. I started from the wrong side. I started from the side that didn't need to be bored out. As a result I would have to drill through the entire piece instead of just a little bit on the correct side. No big deal right? Well I came to need to redo the entire thing because...










When I was finishing the part, I accidentally moved the wrong axis handle and ate off my pulley flange. Ugg... Fail.

Well, it still looks nice anyway so I keep it on my desk. It also helped me realize that I need to change a few things in the design anyway. The Oring groove needed to be wider for instance so I suppose this was a good mistake.









However, I did decide to use the pre-existing plastic ring. Buffer it a small bit with anti-static tape, and then fill the rest with glue. Perfect fit after dry.

Baking the Cake

So last night/morning (5am) I started machining stuff for the very first time! I cut the tube, square bar, and shafting into smaller chunks using some massive horizontal bandsaw, and then turned the round parts down to the correct length. I grabbed some plastic round from the scraps bin and turned down the plastic ring that supports the flux ring. The most important operation of the night was the mods to the 2820 motor I am using for the drum. I chucked the can in the lathe and turned the endbell off. Then I had to bore the mount for the stator to 3/8" using the semi-shoddy drill press.














So this is what I ended up with for the night. Enough material for 2 drums. Everything turned out perfect except the bore for the ring was about 1mm too large. I may end up re-doing that part, or buffering it with tape and glue.

Cake - Beetleweight

	First there was Ron, and then there was the semi-par entertaining stand-in named Pacman. Well I let him kick the bucket last competition so it is time to get on with a new beetle and this time I'm serious... well, kinda :P Cake is going to be a refined version of Attrition. When I built Attrition, most of my concerns revolved around cost instead of effectiveness. As a result, the bot has a few but significant flaws that I hope to address in a downscale. Lets see if they work. 1) Integrate tabs into the frame 2) more precise drum parts 3) Reliable drive system 4) ball bearings! With that said, here is cake as it stands. A beautiful pile of parts.