Wednesday, November 30, 2011

Hunt for the cheapest!

I haven't done any fashion posts for a while and I feel deprived (especially with all the Segboard posts lately). I'm going to show you 2 pairs of shoes that I find similar.

Jimmy Choo Glitter Pumps
Urban Outfitters Glitter Pumps
The question "Am I going to buy an IMU or a pair of shoes?" probably isn't asked by many engineers or fashionistas. I don't meet many people here at MIT who care about fashion. In fact, there's almost an "anti-culture" of dressing up (I'm generalizing, but still). In one sense, practicality drives this trend. You can't wear a chiffon anything while messing with motor grease. However, I try to dress well regardless (just bring another set of clothes or dress differently those days), but most people are either too lazy or too "counter-fashion". Anyway, main point - I like dressing nicely even if a lot of engineers don't and I think it's perfectly fine to be smart and chic.

Nonetheless, I am also really cheap. I almost have to pick between 2 types of tools. Do I buy clothes or parts? The point of the pictures was to show the silliness of price. The Jimmy Choos are $745 and the ones from Urban Outfitters are $49. I'm the type of girl who will go for cheaper if they're similar enough (if you want even cheaper go on ebay). When push comes to shove and you've got to pick between parts for your segway skateboard or nice shoes, the going gets tough :P Basically, always look for the best bargain! 

End rant. 

lolboad frame

Not quite done (needs 2 chains and some trimming on the rod and some shaft collars), but it definitely fleshes the project out :)

It's also entertaining to see a skateboard on the mill (I drilled holes for the motors and wheels). I also got to lathe for once! The spacers from the wheel assemblies were a little too long, so I trimmed them. Lathes are definitely the most scary of all the machine tools. Not sure why though. Probably because it looks like an angry spinning monster of death (and it spews the most coolant on me).

Now for all the code, code, code, cooooooooooooooooooooode............

Tuesday, November 22, 2011

Motor Controller Etching

I'm an h-bridge! :D
Etching is gross and fun :P I've etched a prototype of one h-bridge of Segboard's motor controller to test. I like etching because it's much faster than ordering PCBs (which takes like 2-3 days for shipping and stuff). Also etching is much cheaper. The only problem is that it's pretty messy if you're not graceful (ferric chloride stains your hands and clothes) and your board isn't the nicest looking thing. Oh well, I'm cheap and in college.
I look nice in theory!
I look gross in reality!
Gonna test over Thanksgiving. Yaaaaaaaaaaaaaay!

Tuesday, November 15, 2011

Power Electronics + Segway Skateboard Motor Controller!

Here at MIT, one of our lab classes is Power Electronics (6.131). It's taught by Prof Leeb who's just a bit crazy in the best way. We learn a bunch of basic power management design, (your typical Buck, Boost, and variations) along with some motors. It's my first lab class, and I must say THIS IS MY MOST FAVORITE CLASS SO FAR. Please, please, please if you come to MIT, take 6.131! The thing that bothers me the most about the majority of my classes is that they're all pretty theoretical. I like to make things first-hand, and looking at a bunch of math which doesn't relate to any physical system bores me. 6.131 is the complete opposite. You make the systems you've learned from lecture, which involve lots of building! It's unbelievably satisfying seeing your lecture material turn into a real object you've hand-crafted. But anyhow, I'm getting off topic from what I really want to rant about.

For 6.131 we all have a final project. In fact, it's one of the reasons why I wanted to take this class. I've done more microprocessor projects before, but I've never touched high-power much. For my final project, I'm making *drum roll* SEGBOARD!

You're probably going to see several posts about Segboard soon. Segboard is basically a segway skateboard, based off of the one created by XenonJohn. However, I'm making my own motor controller which changes things up. Not only is my software going to be a bit different, I'm going to have to debug a motor controller. Regardless, physically Segboard should look similar to XenonJohn's.

As some of you might know, my main research deals with wearables (what I like to call fashion engineering), and one might wonder how a segway skateboard has anything to do with that. Well, an addendum to this project is a wearable UI. In order to turn on Segboard, the duty cycle for each motor has to change accordingly, and while this turning mechanism has been implemented with controllers, I want to make a wearable one. My two main ideas for how to do this is through a glove or some kind of jacket, but that's later on (I'll probably first implement Segboard with a hand controller that isn't a true "wearable").  Anyway, I haven't seen many "high-power wearables" (even if through a UI), so I think this could be an excellent example of fashion engineering without LEDs :P This project is legitimately what some might call "hardcore".

I've only the motor controller schematic (below) made now, but I thought I should put it up for fun. Plan for lots of drama, joy, and electronics in the future as I desperately try to finish Segboard before the semester finishes. We'll see if I make it!