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Community Updates

420chan now supports HTTPS! If you find any issues, you may report them in this thread
Free information thread go! by M - Mon, 29 Jul 2013 15:59:46 EST ID:Jr33UkvF No.5815 Ignore Report Reply Quick Reply
File: 1375127986191.jpg -(23049B / 22.51KB, 500x384) Thumbnail displayed, click image for full size. 23049
So, I`m a great fan of free information and I came across this site today

http://ocw.mit.edu/index.htm

A lot of you probaly already know about it. It is a huge source of data regarding prettymuch every type of engineering. Please share with us any interesting free information source regarding engineering.
>>
Betsy Heddlewell - Tue, 30 Jul 2013 09:50:00 EST ID:5ukk83ZK No.5818 Ignore Report Quick Reply
http://wehaslinks.com/search?q=engineering
http://cdn.preterhuman.net/texts/engineering/
http://academicearth.org/?s=engineering
http://bookboon.com/en/engineering-ebooks
>>
Betsy Heddlewell - Tue, 30 Jul 2013 09:52:18 EST ID:5ukk83ZK No.5819 Ignore Report Quick Reply
http://www.khanacademy.org/search?page_search_query=engineering
>>
M - Wed, 31 Jul 2013 12:14:28 EST ID:Jr33UkvF No.5822 Ignore Report Quick Reply
>>5818
wow thanks a lot for those, really interesting stuff there
>>
Doris Bevingdutch - Thu, 01 Aug 2013 01:15:23 EST ID:y4QqaCQl No.5823 Ignore Report Quick Reply
1375334123518.png -(573517B / 560.08KB, 720x400) Thumbnail displayed, click image for full size.
%spoiler that doesn't apply here%
>>
Lydia Grandbury - Fri, 24 Jan 2014 19:11:26 EST ID:CmnGBHIs No.6107 Ignore Report Quick Reply
edx.org or edx.com

BRUK BRUK BRUK BRUK


How to Splice Headphone wires by Shit Chingerwat - Sat, 08 Jun 2013 22:08:06 EST ID:4fpX8pqx No.5726 Ignore Report Reply Quick Reply
File: 1370743686987.jpg -(137781B / 134.55KB, 2096x488) Thumbnail displayed, click image for full size. 137781
Hey look at these headphone wires. I stripped the big black wire. Then I get these 3 wires. But look CLOSELY! See the fuzzy white stuff? It's like a wire inside the wire. Do I need to strip 1 more time? What is that white stuff?

I don't mean to sound rude. Thanks for the help.
5 posts and 1 images omitted. Click Reply to view.
>>
Simon Dunkinfack - Wed, 12 Jun 2013 00:01:31 EST ID:tB60PQ7m No.5744 Ignore Report Quick Reply
1371009691955.png -(20604B / 20.12KB, 383x600) Thumbnail displayed, click image for full size.
EE here, fixing headphone cables isn't difficult. You will need a multimeter to check and triple-check according to continuity, not according to color. You also need to solder, wire-twisting won't cut it. Also, insulate everything from everything as you go... heatshrink is your friend.

I'm pretty sure the white 'n fuzzy is just for wire strength or flexibility, it's definitely not a conductor. Do away with it.
>>
thanks - Fri, 28 Jun 2013 18:50:58 EST ID:mCS3dD2d No.5774 Ignore Report Quick Reply
>>5744
mad props, going to get heatshrink for my projects now
>>
David Tillinghall - Sun, 30 Jun 2013 12:36:00 EST ID:IawMSZ+a No.5776 Ignore Report Quick Reply
I still haven't gotten around to fixing these... but when I do, I'll be sure to tell you.
>>
Nell Duckstone - Sat, 03 Aug 2013 23:53:10 EST ID:x57V/kbu No.5824 Ignore Report Quick Reply
Not pro tips:

Burn the white nylon with a lighter.

THe wires have non-conductive enamel on them. Untwist the wire, and but the enamel off. You need to blow it out quickly, or else you'll make the wire brittle.

Headphone wires are shit to solder. Use a small bit of copper wire as a scaffold.

Stereo is kinda pointless. Your shitty soldering job will hurt the quality of the sound anyway, so just wire it to be mono. I guess for games and movies you want stereo, but for music mono's fine.
>>
David Passlewune - Fri, 24 Jan 2014 13:32:27 EST ID:uEfymhfr No.6106 Ignore Report Quick Reply
bump


Where to find knowledge by Financially challenged student - Sat, 11 May 2013 19:16:29 EST ID:RqK0DV1Q No.5641 Ignore Report Reply Quick Reply
File: 1368314189504.jpg -(775702B / 757.52KB, 1024x768) Thumbnail displayed, click image for full size. 775702
Currently looking for "John Bellamy Digital Telephony" eBook

Help
>>
Shit Clottingdirk - Wed, 15 Jan 2014 02:13:13 EST ID:mbW+t54X No.6097 Ignore Report Quick Reply
Here a pdf 6th result.

>http://www.scribd.com/doc/19134185/Digital-Telephony
>>
Shit Clottingdirk - Wed, 15 Jan 2014 02:14:22 EST ID:mbW+t54X No.6098 Ignore Report Quick Reply
>>6097
Shit just bumped a really OLD thread. sorry,
nb
>>
Ian Cezzlewater - Fri, 16 Oct 2015 04:44:37 EST ID:AoGY9Z/2 No.6812 Ignore Report Quick Reply
1444985077657.jpg -(351760B / 343.52KB, 1123x734) Thumbnail displayed, click image for full size.
>>5641


dmt vape by phil ozwald - Thu, 09 Jan 2014 15:34:34 EST ID:JJaFAAPc No.6096 Ignore Report Reply Quick Reply
File: 1389299674103.jpg -(439981B / 429.67KB, 1850x850) Thumbnail displayed, click image for full size. 439981
Greetings engineers, I really want to vape my DMT through a pen but could not find a kit that would reach low enough temperatures(140-178F). Most vape pens burn in the 400F range and would burn DMT. However I did find a 3-6 volt adjustable battery and 4.5 ohm atomizer. Do you think that is enough resistance to safely reach the desired vaporizing temperatures?


Torsion Springs n stuff by Esther Nadgetag - Fri, 22 Nov 2013 20:26:17 EST ID:0/Zz0xo3 No.6008 Ignore Report Reply Quick Reply
File: 1385169977078.jpg -(77571B / 75.75KB, 800x602) Thumbnail displayed, click image for full size. 77571
Hello Tesla, and may I say, I love your namesake.
I recently became interested in torsion springs, but for the life of me I can't figure out how to buy them. How do I tell what they can hold/do? For instance, this spring:
http://www.amazon.com/Torsion-Spring-065W-62M-270L/dp/B00GO7HIBW/ref=sr_1_14?s=industrial&ie=UTF8&qid=1385166448&sr=1-14
Can someone explain to me what each of the parts of ".065W .62M 270L MW" mean? Thanks a bunch.
>>
Esther Nadgetag - Sat, 23 Nov 2013 17:54:36 EST ID:0/Zz0xo3 No.6009 Ignore Report Quick Reply
1385247276078.png -(13151B / 12.84KB, 438x329) Thumbnail displayed, click image for full size.
>>6008
Okay, so apparently .065W is the "wall" of the spring (the diameter of the metal itself), 270L is the type of metal, MW is "machine wound", and I can only assume .62M is the spring's total diameter.
>>
Shitting Crizzlewodge - Mon, 25 Nov 2013 08:53:44 EST ID:SYi9tkXM No.6012 Ignore Report Quick Reply
1385387624920.png -(78080B / 76.25KB, 199x627) Thumbnail displayed, click image for full size.
>>6009
god damnit
>>
Jack Tillingville - Tue, 03 Dec 2013 20:53:27 EST ID:W6qmmfPc No.6021 Ignore Report Quick Reply
>>6012
Isn't that what you wanted to buy? Have you bought it yet? What? You didn't want to buy it? Why would you click on something if you didn't want to buy it? No, you want to buy it. We'll show it to you in ads in case you forgot. Well did you remember to buy it? BUY IT.


Computer Engineering or Electrical by Thomas Ponnercocke - Wed, 28 Aug 2013 10:37:35 EST ID:daBibOpE No.5856 Ignore Report Reply Quick Reply
File: 1377700655680.png -(525908B / 513.58KB, 605x800) Thumbnail displayed, click image for full size. 525908
I'm going to study either one of these next year. I've had a bit of experience in programming chips and also I've made hobby electrical shit.
Right now I want to get on top of the maths. I've heard that computer engineering uses a lot of linear algebra. I've tried looking it up on Khan Academy but I'm not sure what I should be looking for there. All the linear stuff looks like grade 8 stuff. Can anyone give me some resources on what I should be studying?
Also, an idea on what kind of math I should be studying for EE would be great.
>>
Archie Pundledock - Tue, 07 Jan 2014 09:31:18 EST ID:32nkAQGv No.6093 Ignore Report Quick Reply
http://420math.blogspot.com.au/
http://world.mathigon.org/


komatsu by duramem - Sat, 04 Jan 2014 11:35:12 EST ID:DMR//ClT No.6090 Ignore Report Reply Quick Reply
File: 1388853312050.jpg -(49755B / 48.59KB, 434x489) Thumbnail displayed, click image for full size. 49755
i need a service manual to komatsupc200, i m made a giant grinder with pc200, for stones , if nobody help, i can aid in future with service in this machines.
>>
M - Mon, 06 Jan 2014 03:11:55 EST ID:06ISvFUq No.6092 Ignore Report Quick Reply
>>6090
you could give this a try:
http://www.4shared.com/get/zW9fmycS/komatsu_pc200_series_excavator.html


Long hard and full of seamen by Nicholas Benderwater - Fri, 28 Jun 2013 11:59:37 EST ID:6IjQL0dA No.5769 Ignore Report Reply Quick Reply
File: 1372435177961.jpg -(7251B / 7.08KB, 594x280) Thumbnail displayed, click image for full size. 7251
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?
9 posts omitted. Click Reply to view.
>>
Betsy Heddlewell - Tue, 30 Jul 2013 11:45:10 EST ID:5ukk83ZK No.5821 Ignore Report Quick Reply
>>5813
Ooh, that could work really well with this...
http://montalk.net/science/71/coanda-soliton-effect
>>
Caroline Blatherlock - Sun, 04 Aug 2013 02:38:08 EST ID:TRG9wKw/ No.5825 Ignore Report Quick Reply
>>5821
neat, kind of like an inverted aerospike

http://en.wikipedia.org/wiki/Aerospike_engine
>>
Nigger Besslesidge - Sun, 25 Aug 2013 13:17:23 EST ID:JGGtwP6B No.5851 Ignore Report Quick Reply
Would this be dangerous to the crew?
>>
Charlotte Tootlock - Sun, 01 Sep 2013 00:43:00 EST ID:mSiCExQ8 No.5863 Ignore Report Quick Reply
>>5851
I dunno, I don't think there's a lot of research into electromagnetic fields within batteries.
>>
Edward Fonkinhark - Sun, 05 Jan 2014 05:09:18 EST ID:WwPoQj7Z No.6091 Ignore Report Quick Reply
>>5851
is it safe, see giza


Matlab question by Reuben Peblingman - Mon, 23 Dec 2013 20:17:09 EST ID:NOawd64H No.6045 Ignore Report Reply Quick Reply
File: 1387847829013.png -(7707B / 7.53KB, 585x448) Thumbnail displayed, click image for full size. 7707
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'.
Comment too long. Click here to view the full text.
>>
Nell Cricklemit - Mon, 23 Dec 2013 23:44:44 EST ID:hhXpDM2v No.6046 Ignore Report Quick 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.
>>
Jarvis Fushshit - Tue, 31 Dec 2013 20:22:36 EST ID:1toHq8IK No.6088 Ignore Report Quick Reply
>>6046
n=i


Custom PCB services by David Goodworth - Sun, 12 May 2013 21:59:26 EST ID:ZCsBFmhA No.5647 Ignore Report Reply Quick Reply
File: 1368410366720.jpg -(84180B / 82.21KB, 600x411) Thumbnail displayed, click image for full size. 84180
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 ID:4TXNiIqH No.5648 Ignore Report Quick Reply
>>5647
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 ID:pN01ULQG No.5651 Ignore Report Quick Reply
>>5648

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


Microchip programmin' by Jack Bardman - Thu, 13 Jun 2013 20:22:27 EST ID:N2gcVF14 No.5748 Ignore Report Reply Quick Reply
File: 1371169347847.png -(31842B / 31.10KB, 764x428) Thumbnail displayed, click image for full size. 31842
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.
>>
Molly Bollertutch - Sat, 15 Jun 2013 11:53:00 EST ID:BSkmKEqx No.5755 Ignore Report Quick Reply
How much chip can current output?

You may need a buffer to drive the LED but I'm not sure, I haven't read your chip's datasheets.

So read the dam datasheets.
>>
Molly Bollertutch - Sat, 15 Jun 2013 11:54:39 EST ID:BSkmKEqx No.5756 Ignore Report Quick 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.
>>
Molly Bollertutch - Sat, 15 Jun 2013 11:54:59 EST ID:BSkmKEqx No.5757 Ignore Report Quick Reply
>>5756
through once*
>>
Edwin Fivingchatch - Sat, 15 Jun 2013 17:16:51 EST ID:N2gcVF14 No.5759 Ignore Report Quick 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.

nb


posts by Shitting Pockville - Sat, 27 Jul 2013 03:47:59 EST ID:XObDUDiZ No.5814 Ignore Report Reply Quick Reply
File: 1374911279396.jpg -(115211B / 112.51KB, 480x360) Thumbnail displayed, click image for full size. 115211
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.
>>
Phyllis Blublingbark - Tue, 30 Jul 2013 06:09:04 EST ID:lDcMJVVm No.5816 Ignore Report Quick Reply
Depends on the radius and depth of the dowel joint mate, im not too sure about the material properties of that wood, or the height of the pieces your joining to these posts.
>>
Phyllis Blublingbark - Tue, 30 Jul 2013 06:19:24 EST ID:lDcMJVVm No.5817 Ignore Report Quick Reply
>>5816
I would also use more than one joint and metal pins to cnnect the pieces, do you have a budget?
>>
Betsy Heddlewell - Tue, 30 Jul 2013 11:31:10 EST ID:5ukk83ZK No.5820 Ignore Report Quick Reply
>>5814
STOP SHITPOSTING, lol.
>>
Jenny Pumbledale - Sun, 25 Aug 2013 22:20:35 EST ID:nWFNG1Eq No.5852 Ignore Report Quick Reply
>>5814
I see what you're doing. Stop plz

nb


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