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Comment: Not Just a Workshop (Score 2) 68

by Narmacil (#44137961) Attached to: In Praise of Hackerspaces

The difference between a hackerspace and a workshop is huge. The key difference is the community, it doesn't belong to anybody so anything goes, it's like hippie commune meets workshop meets research lab minus the proposals and endless journal paper spewing. It's not so much about making the tools available (like techshop does), but more about building a group of engineers, tinkerers, and technodweebs to hang out with after work is over.

  Yeah there's a weird maker movement thing that people are pushing along side it, but hackerspaces are a place to hack, a place to figure out why you keep getting that "the printer is on fire" message. A place to admonish the newbs who tell repost jokes from reddit. You can get a project done alot faster when the guy next to you working on the ARM based LED vest can email you instructions on how that quadrature encoder you found in the drawer in the back outputs grey code in 5 minutes instead of spending half a day online looking for just the right answer.

I'm super glad I found Crashspace in LA, it's like my in person version of slashdot, and I'm living the technodream :D

Comment: Hacking? Really? (Score 1) 40

by Narmacil (#39864305) Attached to: MIT <em>Tetris</em> Hack: Source Code Released

When are people going to realize that hacking is now a meaningless buzzword applied to anything that has thought put into it? I feel like this was a neat side project for a few electrical/software engineers, nothing was co-opted or done without permission, no hardware was repurposed, nothing was "hacked". They just got alot of commercial off the shelf stuff, put it together with a little know-how and did what engineers do every day. I know this was posted here because it's MIT, and everyone loves it to death when they do anything remotely tech related, but lighting up buildings with LED's has been going on forever, there's nothing particularly novel here other than their specific implementation, no advances in tech have been made.

Maybe I'm jaded...

Comment: We need some new scientists here. (Score 1) 243

by Narmacil (#37892198) Attached to: The Weight of an e-Book

I'm not sure they're understanding how anything works, it seems like they just figured OH HEY ELECTRONS HAVE MASS I MUST BE SMRT. Here's why.

When you download an E-book from amazon, electrons aren't directly transferred to your tablet, a memory chip is burned, or bits are flipped, to represent the book in memory. (so either a magnetic or optical piece of information is stored by changing the configuration of mass that is already present) This would if anything remove mass from the e-reader, because electrons from the battery that are used to change the configuration of the memory would be lost as heat energy.

now when you charge the battery it might gain a little mass, but electrons don't just hang around once they flow in from the interwebs (that's not how it works :D)
I'm fairly certain some people need to go back to school, and then those people who wrote an article need to go back to journalism school.

Sincerely, your friendly neighborhood rocket engineer :D

Comment: Re:Mars is closer and easier to send people to (Score 1) 298

by Narmacil (#37728884) Attached to: Why Mars Is Not the Best Place To Look For Life

that part in parenthesis, about terraforming, is the point. You would terraform mars and build the facilities there to make it self sufficient. Biosphere is wayyyy too small scale. We're talking a planet wide population, not just a tiny outpost. You'd have factories, mines, farms, cities. Forests. Think Red Mars (it's a good book, read it)

Comment: Stick to ME, decide to double major later (Score 5, Interesting) 296

by Narmacil (#37297416) Attached to: Ask Slashdot: Best Second Major For a Mechanical Engineer?

If you would like to work on automobiles I recommend sticking with ME, and just doing that for now. Mechanical engineering is quite an undertaking on its own and if you double major, plan to spend at least 6 or 7 years in college to get a good understanding of both subjects. If you try to double major with mechanical engineering as one of the majors in the standard 4 years, you will either not gain a satisfactory understanding of the fundamentals and theory or you won't have any time to participate in the practical non-classroom experiences that make a mechanical engineering degree worthwile. I would recommend joining the Baja or formula SAE team at your university or college to get a better understanding of what goes into real world vehicle design, also project oriented teams look great on the resume. You will pick up a little CS and EE in Mechanical engineering if your school is doing it right. You might want to get a green minor if you're interested in biodeisel and low carbon emmisions vehicles, but make sure your university offers this first. Getting the math minor is easy, but probably won't do alot for you in the long run (most mech e's have one by default).

And Controls theory is definately a mech E subject, you can get very in depth in mechatronics and controls courses offered through a mechanical engineering department, and you'll get alot more real world hands on examples than you would in an EE course (EE's tend not to care about mechanisms, and are more interested in the electric theory) I would say if you're interested in cars, go the ME route and stick to it.

(This advice is coming from a practicing Mechanical Engineer who got his BSME in 4 years (at Virginia Tech)) I focused on robotics (CHARLI and RAPHaEL were my pet projects) but had alot of friends who loved cars). I work at SpaceX on rocket stuff now.

Also, you should probably know, the job you get might not be exactly what you planned for or learned the most about in school, but engineering, like life, is an adventure, so stick it out and you'll be sure to have fun.

Comment: Re:SpaceX Company Update is also online (Score 2) 143

by Narmacil (#37116362) Attached to: SpaceX Given Approval For ISS Mission

Unfortunately it's not a code for anything, we just have a frozen yogurt bar at work and they change the two flavors bi weekly. It's normally original tart cause elon supposedly likes that the most, but we get some interesting things every once in a while

And we've got a bunch of programmers, jobs are posted on the main site (careers page) if you're interested

Comment: Re:SpaceX Company Update is also online (Score 0) 143

by Narmacil (#37115660) Attached to: SpaceX Given Approval For ISS Mission

yeah it's not so bad when you don't have to talk to people at the cape all the time. (those guys wake up crazy early, and with the time difference it's like 4am here in Cali when we're doing stuff sometimes)

Hope you had a good summer, and enjoy your last couple days, Thursday the froyo flavor is going to cake batter, should be a high note to go out on.

Robotics

+ - US Team RoMeLa Dominates Robocup Humanoid Soccer->

Submitted by
Narmacil
Narmacil writes "US Team RoMeLa has swept Robocup 2011 winning first place in both the kid size and teen size divisions. CHARLI, America's first full size autonomous humanoid managed to also make the high score record for the teen size division.
http://www.youtube.com/watch?v=llfYoFG7WrY
DARWIN, the kid sized robot beat the Darmschadt Dribblers, the previous world champs, and continued on to the finals to win out."

Link to Original Source

Comment: Mechanical Engineer give U advice (Score 2, Informative) 317

by Narmacil (#33261542) Attached to: Cambered Tires Can Improve Fuel Economy

WAIT hold on guys, I just took a land vehicle dynamics class last semester and if I find my notes.....

Oh here they are one sec let me find the section on Camber caster, and kingpin inclination angles

alright first off rolling resistances

influenced by:
applied load
inflation pressure
tread design
compound

The primary cause of rolling resistance is hysteresis (or internal friction) of the tire material, which occurs as the tire flexes

it increases with
higher load
higher tread design agressiveness (net to gross footprint ratio)
higher tread depth
and decreases with
increasing tire pressure (i.e. less contact patch)

it can be calculated at the contact patch as

F_r= [(s+1)(t_in/R_l)-F_x]cos(a)-F_y*sin(a)

where
F_r is the rolling resistance
s is the slip ratio= (Omega*R_l/V_0)-1
F_x is the longitudinal force (+ driven - braking)
F_y is lateral force
Omega is the angluar velocity of the wheel in rads/second
V is the forward velocity (in ft/s)
a is the slip angle
R_t is the tire radius
and T_in is the driving torque

so on to camber angle

camber angles is the tilt of the center of the tire patch axis from vertical

camber is positive (if viewing from the front of the car) if the tops of the tires are further away from each other than the bottoms

Trucks run positive camber to account for different loads

a small camber is used to account for road crown

some trucks have different camber settings to account for the huge torque their engine can output (this counteracts the torque of the engine's affect on the suspension

mechanics used to bend axels to give cars positive camber ( they shouldnt be doing this anymore >)

so some reasons why camber angle would increase gas efficency

well for one, it makes the effective tire radius larger (by a tiny bit) which should decrease rolling resistance, also, it makes the contact patch smaller, however, depending on the sidewall strength of your tires, this could merely cause more internal hysteresis friction and decrease your effective gas milage

one of the big reasons you probably should not do this is... most consumer tires are manufactured assuming no camber angle, so you'd probably run into some issues with tires wearing out quickly. Also, if you, like most people, forget to check tire pressure before every ride, it would probably be fairly easy to blow out your sidewall in a tight corner, especially if you were running with a heavy load

and if you're especially stupid, and put too much negative camber, you could probably screw up your suspension geometry enough to make your tires move further than the designed rattle space in you car (the open area where the suspension can move) and perhaps your tires would rub on the inside of the wheel wells before the suspension bottomed out.

but it really depends on the type of suspension your car has (and there's wayyyyy to many to list) to get a definite answer as to whether this is doable or advisable. I would go with the factory recommended settings personally and just firkin keep your tire pressure high enough (the recommended amount) and you'll save a TON on gas

oh and a warning, ALWAYS REPLACE REAR TIRES if you're only gettin 2 tires, if you replace the front tires (regardless of a front or wheel rear drive car) only, you could potentially put your car in an oversteer condition, and that is what causes people to lose control, and spin out, unless you're a formula 1 driver and you know WTF you're doing, always keep your car in an under steer condition (i.e. more traction in the back dawg)

This is what i got for taking a land vehicle dynamics class, i hope you find some of it useful

Government

Lessig For Congress? 137

Posted by kdawson
from the played-by-jimmy-stewart dept.
luge writes "With the unfortunate passing of Congressman Tom Lantos, parts of Silicon Valley and San Francisco will be holding a special election in June to send a replacement to Congress. Given the area, it would be great to have someone who is both tech- and policy-aware fill the seat — and it looks like that just might happen. Lawrence Lessig has apparently bought 'change-congress.com.' A 'Draft Lessig' group is forming on Facebook, featuring some of Lessig's old co-workers at Harvard and Jimmy Wales, among others. No word from Lessig himself yet, but he's been increasingly vocal about politics of late. If it happens, it would be a huge step forward for the representation of technology in Washington."

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