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Long hard and full of seamen

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- Fri, 28 Jun 2013 11:59:37 EST 6IjQL0dA No.5769
File: 1372435177961.jpg -(7251B / 7.08KB, 594x280) Thumbnail displayed, click image for full size. Long hard and full of seamen
Say, would there be any practicality to powering a submersible by constructing the hull out of two metals, to work as a giant salt-water battery?
11 posts omitted. Click View Thread to read.
Nigger Besslesidge - Sun, 25 Aug 2013 13:17:23 EST JGGtwP6B No.5851 Reply
Would this be dangerous to the crew?
Charlotte Tootlock - Sun, 01 Sep 2013 00:43:00 EST mSiCExQ8 No.5863 Reply
I dunno, I don't think there's a lot of research into electromagnetic fields within batteries.

Matlab question

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- Mon, 23 Dec 2013 20:17:09 EST NOawd64H No.6045
File: 1387847829013.png -(7707B / 7.53KB, 585x448) Thumbnail displayed, click image for full size. Matlab question
I'm trying to write the following in Matlab

function [m] = calculatem(n)
syms x,
m = round (fzero('(x^n)*exp(-x) - 10^(-n)', 100));

but I keep getting the error,

Error using fzero (line 289)
FZERO cannot continue because user supplied expression ==>
(x^n)*exp(-x) - 10^(-n)
failed with the error below.

Error in inline expression ==> (x^n)*exp(-x) - 10^(-n)
Undefined function or variable 'n'.

What gives? I feel like n is defined???

If I substitute n for the a value, for example, 5, I get the exact answer I expected. But I can't have it so I have n in that line of code.
Nell Cricklemit - Mon, 23 Dec 2013 23:44:44 EST hhXpDM2v No.6046 Reply
If you don't explicitly give MATLAB a value for n it treats it as a string value and shits the bed when you try to use it in an equation.

Just give n a value in the script and it'll work.

Custom PCB services

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- Sun, 12 May 2013 21:59:26 EST ZCsBFmhA No.5647
File: 1368410366720.jpg -(84180B / 82.21KB, 600x411) Thumbnail displayed, click image for full size. Custom PCB services
Anyone here know of a good site for ordering small batches (<5) of custom PCBs? Need some 4 layer boards.
Jack Peddlewell - Sun, 12 May 2013 23:55:35 EST 4TXNiIqH No.5648 Reply
If time isn't an issue, try oshpark.com. It's a batch pcb service, so you're limited to the standard stackup, and the turn time can be a few weeks. but that's probably going to be one of the cheapest routes.

If you have a little more money to spend, silvercircuits.com is also a good deal with a slightly quicker turn time. Plus they are good about working with you on more complex designs (plated slots, cutouts, odd shapes, etc.)

If speed is your priority, there are services like pcbfabexpress and protoexpress that can get it done in less than a week, but prepare to pay much more for a 4 layer board.

I've used all of these services in the past and haven't had any issues.
Cornelius Bivingnick - Wed, 15 May 2013 21:54:45 EST pN01ULQG No.5651 Reply

Thanks man, I'm gonna shoot oshpark an email.

Microchip programmin'

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- Thu, 13 Jun 2013 20:22:27 EST N2gcVF14 No.5748
File: 1371169347847.png -(31842B / 31.10KB, 764x428) Thumbnail displayed, click image for full size. Microchip programmin'
Just got a microchip in the mail and I'm trying to learn my way around.

Just trying to turn on a LED right now and it's not working. My pickit 2 reads/writes/verifies just fine. It just won't light up the LED no matter where I put it.

Here's my circuit and code. I don't know if it's user error or the chip is faulty.
1 posts omitted. Click View Thread to read.
Molly Bollertutch - Sat, 15 Jun 2013 11:54:39 EST BSkmKEqx No.5756 Reply
oh and from looking at your code, I mean I don't really know how that particular chip works but I feel like it goes through ones and done. So it might actually be turning the LED on for a fraction of a second.

Try having an infinite loop on PORTB=1 or a latch of some sort, that might fix it.

Basically play around with it.
Edwin Fivingchatch - Sat, 15 Jun 2013 17:16:51 EST N2gcVF14 No.5759 Reply
Well, I got it working.

Had no external oscillator, settings in mikroC was expecting there to be one, changed it over to use internal osc. Bam.



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- Sat, 27 Jul 2013 03:47:59 EST XObDUDiZ No.5814
File: 1374911279396.jpg -(115211B / 112.51KB, 480x360) Thumbnail displayed, click image for full size. posts
I have some posts that I cut too short and already cemented into the ground. I need to extend them. I just need a secure way of adding an extention on top of them. Would a single dowl joint and some glue be strong enough or would there be problems with this. I want these extentions to be strong enough to handle my body weight so they can never have any structural weakness.
1 posts omitted. Click View Thread to read.
Phyllis Blublingbark - Tue, 30 Jul 2013 06:19:24 EST lDcMJVVm No.5817 Reply
I would also use more than one joint and metal pins to cnnect the pieces, do you have a budget?

Making a leaf-shutter

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- Thu, 02 May 2013 03:52:34 EST i1S+U/Hc No.5608
File: 1367481154675.jpg -(39980B / 39.04KB, 581x300) Thumbnail displayed, click image for full size. Making a leaf-shutter
Just asked this in /Howto/ but it definitely belongs here..

I'm looking on making something very useful, and there's a piece inside that will resemble the opening/closing action of a shutter lense.

Anybody know of where I can find schematics for making the leaf-shutter, without necessarily having the lense? I won't be using this for a camera, so don't need the complexity of it all, just need that useful open-close capability of it. Also it would likely be manually operated so no need for motors/batteries.
Hannah Honeywell - Thu, 02 May 2013 13:52:41 EST Jr33UkvF No.5609 Reply
What exactly do you want from /tesla/?
I could draw that ho in 3D and make parts drawings and all that shit, but if you`re smart enough to "make something very useful" you can probaly use the pic you have there to make the shutter yourself.
what is this "something very useful" anyway?
Huang Laoshi - Fri, 03 May 2013 03:26:25 EST i1S+U/Hc No.5615 Reply

Congratulations you can make a 3D layout, as can so many people here. You've proven you're full of shit by not providing anything useful for OP,and even more so by just talking about what you "could" do.. If you actually "could" do it. You sound more like a kid who just pirated a graphic design program for the first time and thinks he's capable of anything now.

Eliza Nockledark,

I don't know much about making a shutter lense (though not claiming to be an ultimate badass running Maya,) but I know you're going to be looking at getting specialized parts for that type of project. Also this provides more of an in-depth look at what's inside the leaf shutter that gives it its capability.


It seems difficult, but if it's not for a camera and just the shutter action is needed then it should make things a hell of alot simpler, and this would just give an idea.

Future engineer

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- Sun, 08 Jul 2012 22:57:44 EST 442CA/QK No.4467
File: 1341802664058.jpg -(32112B / 31.36KB, 600x435) Thumbnail displayed, click image for full size. Future engineer
Hey, i am going to be a senior in highschool and going to start applying for schools. I know i want to study some type of engineering i am just not sure what field yet. I like working with my hands, working on computers(cad, etc), and dealing with things from a logical aspect but i also like the creative/design aspect of structural or civil engineering(i guess). Just wondering what jobs are needed in each field and why are some other fields of engineering i should look into beside the mainstream ones.

Tl:dr what fields of engineering should i look into. Creative, logical and prefer working with my hands or on computers. Going to be a senior in hs.
3 posts and 1 images omitted. Click View Thread to read.
Jarvis Drummerbare - Fri, 19 Jul 2013 18:24:03 EST nl9igvSv No.5798 Reply
I'm an electrical engineering student and I want to be a doctor or an astronaut or a race car driver...

what do?
Charles Hizzleforth - Wed, 07 Aug 2013 18:02:15 EST lUGyyceD No.5830 Reply
my ent doctor was actually an EE for a while. he decided it wasnt for him, took some classes and went to med school.
Med school dont care what degree you are, as long as you have all the pre-req classes, which are like . .. 18 hours?
Hedda Benkindun - Mon, 12 Aug 2013 20:28:41 EST j23CgD3m No.5835 Reply
1376353721013.jpg -(178805B / 174.61KB, 640x448) Thumbnail displayed, click image for full size.
Engineering Student here

My school offers a bunch of engineering degrees from UGrad to Grad, are you looking to just get a BSc or maybe a Masters of PhD?

For just a BSc and getting a job somewhere:
-Petroleum, Chemical, or Mechanical are your top 3
-Civil and Electrical are good as well, but lower salaries if that's your forte but from what I understand they are 'less intense'
for a BSc in Biomedical Engineering...it's a new sector, but a BSc may leave you unemployed (talking to some former classmates) however it's just a small sector and is growing, by the time you graduate in 5 or 6 years it'll be all gravy I imagine

Going for the Masters:
Biomedical, Chemical, Petroleum hands down are the best. Then again anything engineering with a masters won't be a bad choice. These jobs are well needed in the private and public research sector at Master's level

Mechanical and other engineerings I didn't list will be good here, but IMO better off cashing out at BSc and going to work unless you want more schooling

For biomedical that is a shit ton of research, if you go this route I suggest getting a minor or maybe another degree (like neurobiology or nanotech) to specialize yourself even more.

I can't say too much about the other engineerings but off the top of my head Electrical Engineering and Civil Engineering are relatively not is demand as Biomed, mech, petroleum and chem at the PhD level.

Basically the more schooling you get the better, especially for Biomed, chemical, and Mechanical as well as petroleum. but better off cashing out at petroleum with a BSc because they start very high relative to schooling amounts compared to other degrees at BSc.

Where are you located? I recommend at least applying to UTD (university at texas at dallas), their undergrad program for engineering is great and they give generous scholarships, full tuition with semesterly stipends. This is what I'm doing for undergrad, I should get some more scholarship for my Grad school next year and finish up my grad degree with my saved money.

Take AP science classes too, especially physics and/or chemistry and try to take Calculus in high school if you can.

If you tell me more of your strengths I can better assist you. I'm basically an engineering adviser's assistant so yea

Getting into electronics

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- Sat, 20 Jul 2013 06:45:59 EST o9cZTHsI No.5803
File: 1374317159421.jpg -(81345B / 79.44KB, 480x574) Thumbnail displayed, click image for full size. Getting into electronics
Hey /tesla/,

since it's summer over here and I've got some free time, I would like to get into electronics in general and later Arduino, but I've got pretty much no idea where to start. I had to take a course dealing with boolean logic, so I know stuff like relational logic, graph theory, boolean algebra (functions, normal forms, Karnaugh maps), logic circuits and the basics of finite-state automata and flip-flops, but never got to actually use them - thought this might come in handy. I also know C/C++, Java, some scripting languages and I've started messing with reverse engineering/assembler lately.

Where should I start? Anyone got some book recommendations? What should I buy if I want to mess around with this kind of stuff?

Ernest Madgekick - Tue, 23 Jul 2013 13:13:52 EST KH36wMpB No.5811 Reply
Titles of the books should be something like basic analog electronics and amplifiers

Multimeter+ PSU + fuses+ breadboard + pliers

Concrete walls with ridges

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- Sat, 11 May 2013 02:00:51 EST qDfqjsMS No.5635
File: 1368252051592.jpg -(15327B / 14.97KB, 275x183) Thumbnail displayed, click image for full size. Concrete walls with ridges
Is there any structural purpose for this? It's not supposed to be for aesthetics, is it? It's ugly, and shit builds up in the crevices.
3 posts omitted. Click View Thread to read.
Ebenezer Figglefield - Mon, 13 May 2013 16:26:06 EST LoGagJJL No.5649 Reply
>The specific problem is: The article is fundamentally wrong and packed with errors based on the authors' poor understanding of the subject.

Nigger Hongerfield - Tue, 14 May 2013 09:49:15 EST AInfxL6X No.5650 Reply
didn't proofread, but the formulas are right, that's really about the limitation of my intrest, if you want a better/more accurate verbal explanation just torrent a statics book.

I wasn't shipped the right cord for the ballast. Grow light kit

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- Fri, 19 Jul 2013 23:09:37 EST RWCdnLk6 No.5799
File: 1374289777320.jpg -(85876B / 83.86KB, 800x600) Thumbnail displayed, click image for full size. I wasn't shipped the right cord for the ballast. Grow light kit
I got a cord that plugs into a European outlet that came with the ballast but I live in North America and so that doesn't work, the European cord is 300v but I happen to have another cord lying around that is also 300v, plugs into the ballast, and would fit into my North American outlet.

Should I use this cord I found or have the seller ship me a new cord and wait a week just to be safe?

I was going to post this on /crops/ but I assume you people would be better with electricity and stuff.
2 posts omitted. Click View Thread to read.
Faggy Nickleshit - Sat, 20 Jul 2013 02:25:14 EST RULusGa2 No.5802 Reply
You need to make sure the ballast is rated for a 120V/60Hz input. European power is generally 240V 50Hz. And the wires are a thiner gauge, so they'll get hotter than normal. If you end up using it, check how hot the cable gets for the first few minutes. If it even gets warm, stop using it.
Cyril Blammlehadge - Sat, 20 Jul 2013 11:54:41 EST RWCdnLk6 No.5805 Reply
1374335681320.jpg -(205531B / 200.71KB, 700x935) Thumbnail displayed, click image for full size.

>120V/60Hz input. European power is generally 240V 50Hz.

It's rated both 120/240v and 50/60Hz, so I guess it 's a European/North American ballast.

Thank you for the advice, you're awesome.
Faggy Nickleshit - Sat, 20 Jul 2013 18:17:13 EST RULusGa2 No.5806 Reply
no problem, sounds like you're good to go.


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- Fri, 14 Jun 2013 00:31:06 EST 3jq8QS32 No.5749
File: 1371184266041.gif -(695760B / 679.45KB, 300x194) Thumbnail displayed, click image for full size. How?
I saw this gif in /pol/ and I was wondering how does it even work?
1 posts omitted. Click View Thread to read.
Ernest Snodwill - Fri, 14 Jun 2013 02:31:37 EST 84WsgVqj No.5751 Reply
Basically what Sydney said, it's electronic snake oil.
Basil Gucklepodge - Fri, 14 Jun 2013 12:21:34 EST qmmmZXt+ No.5753 Reply
It kind of works if you're using it like guy in the gif; save electricity by blocking your power outlets
Walter Buzzfield - Tue, 25 Jun 2013 02:43:42 EST EbmglSmN No.5766 Reply
How to reduce energy costs:

Step 0: Don't be retarded.

Step 1: Use higher voltage mains. I switched from 120 to 230v, big improvement.

Step 2: Increase power factor.

Step 3: HVDC LED lighting is stupidly efficient.

Step 4: Solar water preheating for hot water.

Step 5: Solar thermal power - because photovoltaic is not as cool as steam engines.

Lathe Reaming

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- Mon, 08 Apr 2013 12:22:00 EST gdeb+MXi No.5553
File: 1365438120726.gif -(2958B / 2.89KB, 321x133) Thumbnail displayed, click image for full size. Lathe Reaming
Don't know if there's anyone here who took the apprentice route into engineering but il ask anyway, occasionally when reaming a hole using a lathe the hole ends up a few thou' oversize e.g a 1/2" reamer producing a 0.504" hole and i dont know why because the reamer seems to be in good condition
3 posts omitted. Click View Thread to read.
some guy with opinion - Fri, 26 Apr 2013 14:42:36 EST IODwa9Nn No.5600 Reply
is the lathe sitting on complete level ground? also try finding a good speed if its to slow it will heat up fast resulting in overusing coolant, just pay attention to the speed and the color of the metal, make sure its fairly clean of burs and don't speed up slow down whilst in motion.. test an offcut before you find the correct drilling speed
some guy with opinion - Fri, 26 Apr 2013 14:46:57 EST IODwa9Nn No.5601 Reply
i can post a similar picture to you from my engineering book for you if that will help?
Cyril Fimblehood - Thu, 16 May 2013 06:38:28 EST kz85WsFR No.5653 Reply
could the reamer be 2 thou of centre?

Civil Engineering

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- Thu, 02 May 2013 02:54:44 EST +31F/aYC No.5607
File: 1367477684461.jpg -(15091B / 14.74KB, 240x320) Thumbnail displayed, click image for full size. Civil Engineering
CivIl Engineering worth while? is there a high demand for Civil Engineers?
if not, what discipline of engineering is most sought after?
Martha Grimcocke - Thu, 02 May 2013 13:56:50 EST buTeoEHV No.5610 Reply
Check out the post about the job market below.
I don't know how accurate that is to your area, but I've heard out of all the engineering disciplines, civil and architectural are among the least in demand.

As far as highest in demand, I would probably say EE or ChemE? I'm probably a little bit biased being EE though.

Do what you want though, they can all have fairly good hire rates, and it's tough to make it through four years of engineering if you don't like what you're doing.
I spent 12 hours yesterday on a project but I don't mind because I love doing it.
Hannah Honeywell - Thu, 02 May 2013 13:58:27 EST Jr33UkvF No.5611 Reply
every sort of engineers really.
I`m currently on an internship in a mechanical engineering company (I design bridges and other large metal constructions) and there`s a great shortage of people who calculate bridges. appareantly no-one wants to do that shit and the people who do it get payed fuckloads and get their dicks sucked by companies to get them working for their company. I really couldn`t care less about calculating that kind of stuff for a job so I won`t be doing that kind of stuff.
hope this helps.
ps; bridge design is sort of civil engineering and mechanical engineering combined.
Trynd - Tue, 07 May 2013 03:44:52 EST N4X3qNBZ No.5627 Reply
1367912692432.jpg -(137946B / 134.71KB, 700x525) Thumbnail displayed, click image for full size.
Electrical Engineers are in very high demand. For ME's and EE's, only a Bachelor's Degree is required.

There will always be a demand for Water Resources in every community for Civil Engineers. Environmental Engineering is also on the rise.

I heard that for Civil, you're more inclined to get a Masters Degree
Civil Engineering demand is lower in the U.S. at the moment because of the recession, but US Infrastructure is in desperate need of repair.
Forecast: Govt infrastructure (Transportation, Structures, Bridges, Dams, the works) and Environmental Engineering demand ahead

Civil Engineering requires more years of experience for a job.

Honestly, go for what interests you the most.
If you really enjoy Math, go for Electrical Engineering or Computer Science
Manufacturing, Vehicles, Aerospace and Thermal systems (Heating and Cooling ) ----> ME

Bridges, Construction, Water systems, Dams, Pipes, Highways, Environmental---> Civil
I chose Civil Engineering because I enjoy working outside (EE's spend most of their time indoors). Water Resources and Environmental Engineering interests me because they are essential to maintaining a sustainable community.

engine swap not sure how to do.

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- Sun, 12 May 2013 09:40:01 EST mOTxuWnQ No.5644
File: 1368366001927.jpg -(60658B / 59.24KB, 640x480) Thumbnail displayed, click image for full size. engine swap not sure how to do.
how can fit a 347 cobra engine into my 04 saab aero.? i have plenty of tools for metal works but i dont work on cars.
4 posts and 1 images omitted. Click View Thread to read.
Alice Wangerkure - Sat, 08 Jun 2013 17:37:09 EST 32CcdVZd No.5725 Reply

Its not going to happen. At least, not without serious unibody work. If you just want to go faster op get a 3-inch exhaust and a reflash for the computer, it will be much faster.
Simon Dottingbune - Tue, 02 Jul 2013 02:27:11 EST BSkmKEqx No.5780 Reply
Not really...

But you are gonna need a crane because that shit is heavy.

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