Sorry your browser is not supported!

You are using an outdated browser that does not support modern web technologies, in order to use this site please update to a new browser.

Browsers supported include Chrome, FireFox, Safari, Opera, Internet Explorer 10+ or Microsoft Edge.

Geek Culture / [STICKY] The Posting Competition

Author
Message
Dark Java Dude 64
Community Leader
14
Years of Service
User Offline
Joined: 21st Sep 2010
Location: Neither here nor there nor anywhere
Posted: 15th Mar 2016 02:08 Edited at: 15th Mar 2016 02:12
Link
Quote: "I figured you didn't need the hassle of Skype being bad and trying to load 123,456,789,069 new messages in the UI thread if you ever came back. "
Ahhh, very well then. Much appreciated.

You guys raise some interesting points. Going into this election season, I found myself on the conservative side for sure. I quite liked Trump, but that was before I had done much research or thinking on him. Right now I definitely lay on the liberal side, save a few key issues.

Comet, you raise a great point about caring for the American people first... I have always though that Trump's border control antics are insane, but I suppose I do support controlling (i.e. reducing) immigration if it's for the benefit of the country itself. Beyond that, however, I think that immigrants should be given a little more slack.

I disagree with Trump's various economic policies -- getting rid of the healthcare system that Obama initiated, however much that may support a free market, seems a step in the wrong direction -- socialized healthcare is a hallmark of developed countries. His tax policies also seem a little impractical, but I'm not afraid of those; I don't think he could ever get any of those passed.

I think Clinton could beat Trump quite well actually -- I don't feel the American public collectively has the conscience to actually elect Trump in a general election.

As it stands, if it came down to Trump and Clinton, I'd probably vote for Clinton. Sanders and Trump? No idea. Clinton and another republican? The republican, reluctantly.

It surprises me how much non Americans know about the political state of the United States -- I suppose it would make sense that the eyes of many countries are on us right now, as we work to elect (arguably) the most powerful person in the world.
"Fat Jeb is a big bushy mistake." - Danald Tromp
Back to top
Profile PM Website
Yodaman Jer
User Banned
Posted: 15th Mar 2016 02:25 Edited at: 15th Mar 2016 02:29
Link
If it came down to Sanders vs. Trump, I would vote Sanders in a heartbeat.

If it comes down to Clinton vs. Trump I will cry as I write-in a name of someone else. Can I write-in a past President who only served one term?

I hate using the party names anymore because both sides have strayed from their original meanings - "republican" used to be a word that wasn't offensive in social circles. Same with "democrat". And as soon as you say "socialist" everyone from both sides freaks out and says "Oh great, they want communism". But as soon as you say "democratic socialist", it seems to not have as much of a negative connotation. It's all in the wording.

I used to lean more on the conservative side of politics, but as the years have come and gone I have found that the GOP seems to be stuck in a rut, from about 60 years ago. They want to hold on to times and policies that just are no longer relevant, and it's quite a bizarre thing, really. But then you have the democrats who are also stuck in a rut and not in anyway progressive, like Obama and potentially Sanders, who actually have been/will be progressive - i.e., Hillary Clinton. Despite this, I would not in anyway classify myself as liberal or democratic. I have opinions from both sides. Both sides, of course, have good points and bad points.

I still would never vote Trump, but I can see why people support him. Putting America first is something the last few Presidents have seemed to have slipped up on. We do need a LOT more jobs here, but we also need to make sure they don't contribute to global warming/climate change. That, ultimately is what scares me about Trump, and Cruz - will they actually care about contributing to climate change? I'm not even sure they realize it's a thing. I think Rubio acknowledges it, however he's definitely not getting the nomination.

Hey, at least sleepy Ben Carson dropped out. That guy seriously looked like he was on sleeping pills every single day.

Also, page.
Slowly compiling code, one byte at a time.
Follow meh blague for more zany thoughts and possibly offensive programming!
Back to top
Profile
Dark Java Dude 64
Community Leader
14
Years of Service
User Offline
Joined: 21st Sep 2010
Location: Neither here nor there nor anywhere
Posted: 15th Mar 2016 02:39 Edited at: 15th Mar 2016 05:35
Link
Yeah, I totally agree with the whole democratic/republican word thing. I don't even care to learn the specific meanings of those words. Liberal and conservative seem to be better defined -- I am somewhat on the liberal side, but really just quite in the middle. A moderate, they might say?

Too bad all of the moderate republicans have dropped out/have no chance. I'd take a moderate conservative over a strong liberal most days, I think. Well wait I have an idea... I should have my cat run! He believes in cute things, and therefore would be a proper president. No other country would have the heart to attack a cat-led America. And free cat treats for all. Socialized cat care, that is. I vote for Dark Java Dude 64's cat!

Lol, Hillary Clinton's main campaign site requires you to click an entry context window thingy (whatever it's called) to indicate that you basically agree that Trump is bad. Nifty!
"Fat Jeb is a big bushy mistake." - Danald Tromp
Back to top
Profile PM Website
Yodaman Jer
User Banned
Posted: 15th Mar 2016 14:30 Edited at: 15th Mar 2016 14:33
Link
So, I have been battling congestion for almost two weeks now. That cold I previously mentioned is pretty much gone but the congestion has remained. Every day I wake up and feel less congested, but this is by far the most stubborn cold I've ever had.

Unrelated, I have been planning my game for quite some time now. I decided I shall make it 2D, top-down view, much in the same way Zelda was top-down. I just need to come with a good dialog system. I will be programming it in AppGameKit, I tried using Stencyl to prototype it but the problem with engines like that is that they basically force you to use their default settings for things and it's very difficult to change anything. I've always wanted to develop it with AppGameKit but I thought I would least get an idea for controls through Stencyl. Not so much
Slowly compiling code, one byte at a time.
Follow meh blague for more zany thoughts and possibly offensive programming!
Back to top
Profile
Dark Java Dude 64
Community Leader
14
Years of Service
User Offline
Joined: 21st Sep 2010
Location: Neither here nor there nor anywhere
Posted: 15th Mar 2016 14:31
Link
I noticed the same with my cold -- it hasn't been quite as severe, but boy, it's been incredibly persistent!
"Fat Jeb is a big bushy mistake." - Danald Tromp
Back to top
Profile PM Website
Yodaman Jer
User Banned
Posted: 15th Mar 2016 14:37
Link
Everyone I know has had this cold for over two weeks. My fiance has actually had it for about a month now, but that's because she refused to go to the doctor at all.

I had the actually cold/flu part for about a week and a half, and now it's just been the congestion lingering. I've been taking decongestants and still sitting in front of a humidifier, and it is working but it is taking FOREVER.

I think it's because the weather has been all over the place these last couple of months. About three weeks ago, we had a huge blizzard, only for the snow to completely melt after two days because the day after the blizzard was in the 50s and the next day got to almost 70... and we've been in the 50s ever since. So germs that normally lay dormant in the winter due to low temps are very much alive and well right now infecting all of us northerners in strange manners.
Slowly compiling code, one byte at a time.
Follow meh blague for more zany thoughts and possibly offensive programming!
Back to top
Profile
Randomness 128
17
Years of Service
User Offline
Joined: 13th Feb 2007
Location:
Posted: 15th Mar 2016 14:50
Link
Quote: "I tried using Stencyl to prototype it but the problem with engines like that is that they basically force you to use their default settings for things and it's very difficult to change anything."


Quote: "Ew"


Ah, so that's why.
320x224
Back to top
Profile PM Email
Yodaman Jer
User Banned
Posted: 15th Mar 2016 14:59 Edited at: 15th Mar 2016 15:00
Link
It's also because in order to publish to desktop Stencyl wants you to pay $99/year. I'd be fine with it if the engine wasn't all buggy though.

Seriously, it used to be pretty stable but lately each version has something broken that renders it almost totally unusable. At least Paul does a good job of keeping up with bug fixes in AppGameKit!
Slowly compiling code, one byte at a time.
Follow meh blague for more zany thoughts and possibly offensive programming!
Back to top
Profile
Randomness 128
17
Years of Service
User Offline
Joined: 13th Feb 2007
Location:
Posted: 15th Mar 2016 15:06
Link
Quote: "Seriously, it used to be pretty stable but lately each version has something broken that renders it almost totally unusable. "

So now it's like all other software!
320x224
Back to top
Profile PM Email
Yodaman Jer
User Banned
Posted: 15th Mar 2016 15:11
Link
Software has always had bouts of unstableness but Stencyl takes the cake with how many versions it's been. There's still one issue in particular where half the time, even if you are running in administrator mode it absolutely refuses to let you save games or projects. Another huge bug was that whenever you attempted to start a new project, some internal array would throw an error because it was "out of bounds". That was a fun one

But besides all that I want to get back into programming from scratch anyway, since it gives you much more control in the end. And the only issues I've ever really had with AppGameKit are the silly file permissions but I got that figured out so it's all good.

How would you implement a text-based dialog system? One way I'm thinking of is to have all the dialog stored in some file somewhere, and when the game loads I load it into an array that is based on a UDT, which would have tags to determine what character the dialog belongs to. Then, whenever the player starts to talk to the NPC it would just access the proper element in the array and display the text. But is there a better way?
Slowly compiling code, one byte at a time.
Follow meh blague for more zany thoughts and possibly offensive programming!
Back to top
Profile
Ortu
DBPro Master
17
Years of Service
User Offline
Joined: 21st Nov 2007
Location: Austin, TX
Posted: 15th Mar 2016 22:59 Edited at: 15th Mar 2016 23:02
Link
Guess who gets to do server maintenance at 3am this Saturday, yay?

Yoda: that works, but if AppGameKit supports it, I would probably query a database for content as needed instead of loading the entire dialog set up front.
Back to top
Profile PM Email Website
Randomness 128
17
Years of Service
User Offline
Joined: 13th Feb 2007
Location:
Posted: 16th Mar 2016 01:08
Link
GLSL is pure chaos. Manually unrolling that loop is faster on my AMD card but slower on my Nvidia card. A dynamic branch always takes the same path during this test but somehow commenting out the other path along with the branch makes the entire shader run at half the speed on one card while the other card is faster with no branches at all. Moving a line of code speeds one card up and slows the other card down. I should work on Exotreve instead! It's written entirely in assembly and there's no caching, no pipelining, and no other software sharing the hardware. It's so gloriously predictable.
320x224
Back to top
Profile PM Email
Yodaman Jer
User Banned
Posted: 16th Mar 2016 13:49
Link
So, I thought about this, and although I don't have code for this I think it would work pretty well.

Instead of loading all the dialog upfront in my game, I could just assign each NPC a "dialog" variable inside of the NPC UDT. Then, using special characters inside of the string, I could then parse through it and have it split up if it reads the special characters. So,. a / could mean new line, and a < could mean to wait for input until the player is done reading the text.

Each NPC (besides quest characters) would also have a "mood" variable with three possible states - happy, sad, and and angry. So each character would also have three dialog strings as well and the correct one would display depending on their current mood.

The main character's responses would also be stored inside each NPC.

The only thing I can think is that this might end up being quite a lot messier, but it's an idea that could work well.
Slowly compiling code, one byte at a time.
Follow meh blague for more zany thoughts and possibly offensive programming!
Back to top
Profile
budokaiman
FPSC Tool Maker
15
Years of Service
User Offline
Joined: 24th Jun 2009
Playing: Hard to get
Posted: 16th Mar 2016 20:08
Link
Quote: "Guess who gets to do server maintenance at 3am this Saturday, yay? "

That's what shell scripts are for.
"Giraffe is soft, Gorilla is hard." - Phaelax
Back to top
Profile PM Email Website
Dark Java Dude 64
Community Leader
14
Years of Service
User Offline
Joined: 21st Sep 2010
Location: Neither here nor there nor anywhere
Posted: 16th Mar 2016 22:14 Edited at: 17th Mar 2016 04:00
Link
Grr, not only does the internet seem to lack greatly in explanations of how modern radio receivers work, but it also lacks severely in logical explanations of how basic things like frequency mixers work. There's lots of articles describing, in very vague terms, what they do, and some that even explain how a diode is a simple mixer, but none of them actually explain how the things actually work at a schematic level! Even page 2 of a Google search has not answered my questions!

EDIT Alright, it was simpler than I thought. I've successfully created a circuit that outputs a frequency the difference of its two inputs.
"Fat Jeb is a big bushy mistake." - Danald Tromp
Back to top
Profile PM Website
TheComet
17
Years of Service
User Offline
Joined: 18th Oct 2007
Location: I`m under ur bridge eating ur goatz.
Posted: 16th Mar 2016 22:26
Link
@Ortu and budokaiman https://www.jitbit.com/alexblog/249-now-thats-what-i-call-a-hacker/
"Jeb Bush is a big fat mistake" -- Donald Trump
https://vt.tumblr.com/tumblr_o2rvwdLLSF1rmjly4.mp4
Back to top
Profile PM Email Website
Yodaman Jer
User Banned
Posted: 17th Mar 2016 04:49 Edited at: 17th Mar 2016 15:00
Link
@TheComet:

That guy is a hero. My favorite script is the coffee one. I should look into doing something similar...

EDIT: Just realized I've had the wrong blog linked here in my signature... the one I had previously was hosted on Blog.com, which is unreliable. This one is hosted on WordPress, and is the one I thought I had linked to in the first place....
Slowly compiling code, one byte at a time.
Follow meh blague for more zany thoughts and possibly offensive programming!
Back to top
Profile
TheComet
17
Years of Service
User Offline
Joined: 18th Oct 2007
Location: I`m under ur bridge eating ur goatz.
Posted: 17th Mar 2016 21:34 Edited at: 17th Mar 2016 21:37
Link












"Jeb Bush is a big fat mistake" -- Donald Trump
https://vt.tumblr.com/tumblr_o2rvwdLLSF1rmjly4.mp4
Back to top
Profile PM Email Website
Ortu
DBPro Master
17
Years of Service
User Offline
Joined: 21st Nov 2007
Location: Austin, TX
Posted: 17th Mar 2016 23:36
Link
We are expanding a datastore on a SAN, then relocating a VM from its current datastore to the newly expanded one, reprovision the disk size and then extend the partition. It's not too complicated and should be kind of interesting, just going to take a while to move the data
Back to top
Profile PM Email Website
Dark Java Dude 64
Community Leader
14
Years of Service
User Offline
Joined: 21st Sep 2010
Location: Neither here nor there nor anywhere
Posted: 18th Mar 2016 01:05 Edited at: 18th Mar 2016 01:08
Link
Voltage regulator/op amp melter!

"Fat Jeb is a big bushy mistake." - Danald Tromp

Attachments

Login to view attachments
Back to top
Profile PM Website
TheComet
17
Years of Service
User Offline
Joined: 18th Oct 2007
Location: I`m under ur bridge eating ur goatz.
Posted: 18th Mar 2016 07:19
Link
1) 10 ohm resistor with 80V. Your zener diode will explode, along with the 10 ohm resistor.
2) Why are you dividing the voltage in half again with 10 Meg? Just use a more suitable zener.
3) 10 Meg is a lot. It will introduce a lot of noise into your circuit.
"Jeb Bush is a big fat mistake" -- Donald Trump
https://vt.tumblr.com/tumblr_o2rvwdLLSF1rmjly4.mp4
Back to top
Profile PM Email Website
Dark Java Dude 64
Community Leader
14
Years of Service
User Offline
Joined: 21st Sep 2010
Location: Neither here nor there nor anywhere
Posted: 18th Mar 2016 07:45 Edited at: 18th Mar 2016 07:57
Link
Quote: "10 ohm resistor with 80V. Your zener diode will explode, along with the 10 ohm resistor."
Correction to my original text then: "Self destroying voltage regulator!"

Quote: "Why are you dividing the voltage in half again with 10 Meg? Just use a more suitable zener."
That's an option? Awesome, good to know! I figured they were like regular diodes, typically 0.3 or 0.7 or whatever Vd. Oh, and, I'm doing it correctly by reverse biasing it, right? Or should it be forward biased? It seemed a fair bit more stable reverse biased as I have it (I'd assume so with zener diodes specializing in zener breakdown and all that).

Quote: "10 Meg is a lot. It will introduce a lot of noise into your circuit."
Good point, I'll have to keep that in mind.
"Fat Jeb is a big bushy mistake." - Danald Tromp
Back to top
Profile PM Website
Seditious
11
Years of Service
User Offline
Joined: 2nd Aug 2013
Location: France
Posted: 19th Mar 2016 02:56
Link
Why are the arrows for current facing the wrong way?



http://www.allaboutcircuits.com/textbook/semiconductors/chpt-8/divided-feedback/

Back to top
Profile PM
Dark Java Dude 64
Community Leader
14
Years of Service
User Offline
Joined: 21st Sep 2010
Location: Neither here nor there nor anywhere
Posted: 19th Mar 2016 05:39
Link
They're demonstrating that one of the effects of divided negative feedback is reversed current! Current will always flow from ground when connected to both an input and an output of an op-amp. Basic stuff bro.

Nah, but really, when I first learned to read schematics with conventional current flow in mind as opposed to actual current flow, everything made much more sense. Never could figure out why the electrons went the opposite way of the arrow through a diode or transistor.
"Fat Jeb is a big bushy mistake." - Danald Tromp
Back to top
Profile PM Website
Seditious
11
Years of Service
User Offline
Joined: 2nd Aug 2013
Location: France
Posted: 19th Mar 2016 12:40
Link
Quote: "Current will always flow from ground when connected to both an input and an output of an op-amp."


Wot. Why would it flow from a lower potential to a higher potential?

Quote: " Basic stuff bro"


Good, I'm still learning the basics.
Back to top
Profile PM
Dark Java Dude 64
Community Leader
14
Years of Service
User Offline
Joined: 21st Sep 2010
Location: Neither here nor there nor anywhere
Posted: 19th Mar 2016 17:25 Edited at: 19th Mar 2016 17:33
Link
Sarcasm! Please don't take what I said as factual! I figured you were beyond the beginner level and would catch my sarcasm. I feel bad about the "basic stuff bro" comment now.

In case you don't know, conventional current and actual current are two different things. Actual current is the direction electrons actually flow, which is from negative (ground) to positive (power supply). However, (as far as I know) when electricity was first discovered, scientists thought that electrons flowed from positive potential to negative potential (hence their namings). Electrical engineering developed during the time period of that understanding, hence assuming that current flows from positive to negative became standard. Later, we found that electrons in fact flow the opposite way, but it was too late to change everything around. Hence, conventional flow, standard to electrical engineering symbols, is opposite of actual current flow.
"Fat Jeb is a big bushy mistake." - Danald Tromp
Back to top
Profile PM Website
TheComet
17
Years of Service
User Offline
Joined: 18th Oct 2007
Location: I`m under ur bridge eating ur goatz.
Posted: 19th Mar 2016 18:07 Edited at: 19th Mar 2016 18:08
Link
@Seditious The current is drawn incorrectly and the wrong way. The correct notation is to use inline arrows for current and external arrows for voltage, like this:



I can't stop watching this:



Those people have no idea what they just witnessed, they're all just shocked.



And you've got Jimmy Page doing things like



"Jeb Bush is a big fat mistake" -- Donald Trump
https://vt.tumblr.com/tumblr_o2rvwdLLSF1rmjly4.mp4
Back to top
Profile PM Email Website
Dark Java Dude 64
Community Leader
14
Years of Service
User Offline
Joined: 21st Sep 2010
Location: Neither here nor there nor anywhere
Posted: 19th Mar 2016 18:53 Edited at: 19th Mar 2016 18:54
Link
Voltage reg 2.0! I added a capacitor of generic value, inspired by other designs I have seen. I presume it should help increase output stability under sudden load changes. I also offloaded the current sourcing work to a MOSFET, protecting the delicate little op amp!

"Fat Jeb is a big bushy mistake." - Danald Tromp

Attachments

Login to view attachments
Back to top
Profile PM Website
Randomness 128
17
Years of Service
User Offline
Joined: 13th Feb 2007
Location:
Posted: 19th Mar 2016 22:30
Link
I wrote this line of GLSL code today:
320x224
Back to top
Profile PM Email
Dark Java Dude 64
Community Leader
14
Years of Service
User Offline
Joined: 21st Sep 2010
Location: Neither here nor there nor anywhere
Posted: 19th Mar 2016 22:46
Link
Hugh? Are you there Hugh?

Also, saw someone write this bright sentence today:
Quote: "By the way, you spelt available wrong"
"Fat Jeb is a big bushy mistake." - Danald Tromp
Back to top
Profile PM Website
Seditious
11
Years of Service
User Offline
Joined: 2nd Aug 2013
Location: France
Posted: 20th Mar 2016 02:18
Link
Quote: "In case you don't know, conventional current and actual current are two different things."


HOW VERY DARE YOU. Just kidding. I did wonder if the person who made that image meant to show electron flow.

Quote: "@Seditious The current is drawn incorrectly and the wrong way. The correct notation is to use inline arrows for current and external arrows for voltage, like this"


Oh I see, thanks.
Back to top
Profile PM
TheComet
17
Years of Service
User Offline
Joined: 18th Oct 2007
Location: I`m under ur bridge eating ur goatz.
Posted: 20th Mar 2016 16:51 Edited at: 20th Mar 2016 16:54
Link
Rnd128 wrote: "I wrote this line of GLSL code today:
"




(That's Jack Hues in case anyone weas wondering)
"Jeb Bush is a big fat mistake" -- Donald Trump
https://vt.tumblr.com/tumblr_o2rvwdLLSF1rmjly4.mp4
Back to top
Profile PM Email Website
Randomness 128
17
Years of Service
User Offline
Joined: 13th Feb 2007
Location:
Posted: 20th Mar 2016 18:42
Link
Sadly that line is now:
320x224
Back to top
Profile PM Email
TheComet
17
Years of Service
User Offline
Joined: 18th Oct 2007
Location: I`m under ur bridge eating ur goatz.
Posted: 20th Mar 2016 19:41
Link
What's the point of abs() if you're raising it to an even number? And then not using abs() when multiplying it with hue?
"Jeb Bush is a big fat mistake" -- Donald Trump
https://vt.tumblr.com/tumblr_o2rvwdLLSF1rmjly4.mp4
Back to top
Profile PM Email Website
Randomness 128
17
Years of Service
User Offline
Joined: 13th Feb 2007
Location:
Posted: 20th Mar 2016 20:52
Link
Quote: "What's the point of abs() if you're raising it to an even number? And then not using abs() when multiplying it with hue?"


The result of GLSL's pow is undefined if the base is negative.
320x224
Back to top
Profile PM Email
TheComet
17
Years of Service
User Offline
Joined: 18th Oct 2007
Location: I`m under ur bridge eating ur goatz.
Posted: 20th Mar 2016 21:56
Link
> hue
> negative

choose one
"Jeb Bush is a big fat mistake" -- Donald Trump
https://vt.tumblr.com/tumblr_o2rvwdLLSF1rmjly4.mp4
Back to top
Profile PM Email Website
Crazy Programmer
AGK Developer
20
Years of Service
User Offline
Joined: 6th Sep 2004
Location: Lost in AGK
Posted: 20th Mar 2016 22:40
Link
Lol
Download My Games for Android. Made with AGK.
Jellyfish Dive- https://play.google.com/store/apps/details?id=com.CrazyProgrammerProductions.my_JellyFishSwim
Brick Destroyer - https://play.google.com/store/apps/details?id=com.CrazyProgrammerProductions.my_BrickDestroyer
Ping Bong - https://play.google.com/store/apps/details?id=com.CrazyProgrammerProductions.my_Pong_Ping_Bong
Back to top
Profile PM Email Website
Seditious
11
Years of Service
User Offline
Joined: 2nd Aug 2013
Location: France
Posted: 21st Mar 2016 22:40 Edited at: 21st Mar 2016 22:42
Link
So I'm playing with some very cheap 1W leds I ordered a while back, operating at about 4.1v 250ma (which should be correct, approx. 1W) but testing them with lower currents. I set my CC/CV supply to 5v 100ma and when I connected two of these leds in parallel they both briefly shone brightly and then one went off and the other went dim. Dodgy leds, dodgy power supply, or dodgy knowledge of how this all works? I have tested a couple of others individually at full power and they work just fine.
Back to top
Profile PM
TheComet
17
Years of Service
User Offline
Joined: 18th Oct 2007
Location: I`m under ur bridge eating ur goatz.
Posted: 21st Mar 2016 23:01 Edited at: 21st Mar 2016 23:05
Link
Are you sure you were limiting the current to 100mA?

Also, if you think you can connect two diodes in parallel to "double the current", you are terribly mistaken. I will laugh at you as you watch the first diode explode, promptly followed by the second.
"Jeb Bush is a big fat mistake" -- Donald Trump
https://vt.tumblr.com/tumblr_o2rvwdLLSF1rmjly4.mp4
Back to top
Profile PM Email Website
Yodaman Jer
User Banned
Posted: 21st Mar 2016 23:34
Link
i klame dis aveiluble pints
Slowly compiling code, one byte at a time.
Follow meh blague for more zany thoughts and possibly offensive programming!
Back to top
Profile
Seditious
11
Years of Service
User Offline
Joined: 2nd Aug 2013
Location: France
Posted: 21st Mar 2016 23:51 Edited at: 22nd Mar 2016 00:44
Link
I'm pretty sure the current is limited (I've tested with a DMM) but I'm not quite sure how CC works on these things and if there is any period where it might allow a higher current before limiting it. I'm such a n00b. It's entirely possible that the leds are faulty since a) they are cheap chinese things, and b) they were shipped in an envelope with no antistatic materials. Otherwise I'm stumped. Like a 1-legged donkey.

Quote: "Also, if you think you can connect two diodes in parallel to "double the current", you are terribly mistaken."


Not at all, I just set the current lower to be a bit safer when testing the leds. I wanted to try some series/parallel stuff with a few leds to see how well it works, and how evenly the leds light when in parallel. NOT VERY EVENLY LOL

EDITLOL

I just did some experimenting with a couple of flat top leds and it seems when they are first connected they flash very bright for a very brief (milliseconds) period before going down to their normal brightness. After tapping the wire against the led's anode to make and break connection several times the leds now appear damaged. So it's the fault of the power supply. Is it normal for a CC supply to allow a large inrush current just before limiting a split second later? A bit more testing reveals having the voltage limit set too high blows up the led, presumably because of the less-than-instantaneous current limiting. Should it really be necessary to keep the voltage low before connecting and then ramp it up afterwards? Is this a crappy dc-dc converter? Am I a noob?
Back to top
Profile PM
Dark Java Dude 64
Community Leader
14
Years of Service
User Offline
Joined: 21st Sep 2010
Location: Neither here nor there nor anywhere
Posted: 22nd Mar 2016 06:17
Link
I was thinking about this the other day and wondering a similar thing -- if the supply's current limiting is software controlled, there would be a slight delay before it lowers the voltage to limit current. A solely hardware method should theoretically limit instantaneously?
"By the way, you spelt available wrong"
Back to top
Profile PM Website
Seditious
11
Years of Service
User Offline
Joined: 2nd Aug 2013
Location: France
Posted: 22nd Mar 2016 13:59 Edited at: 22nd Mar 2016 14:58
Link
You'd imagine so. From doing a bit of reading it seems CV/CC supplies don't instantly switch from CV to CC, which would explain the spike. I've read a few datasheets for leds and they mention gradually powering up the led from a CC supply, since if the voltage limit is too high to start with it can overshoot the current threshold briefly (thus damaging or destroying semiconductor junctions). Presumably proper led drivers do something like this, since I've never noticed such problems when using them.

I do wonder though, if it's suitable to just set the voltage limit to the upper specification of the led (for example many are specified as 9-12v, so 12v as the limit) in order to limit the surge to just above the normal operating current, assuming the upper voltage specification isn't totally above the knee voltage (does a led operate exactly on its knee voltage? no idea).

http://www.mouser.com/pdfdocs/lumiled-avoiding-current-spikes.pdf
http://www.farnell.com/datasheets/1636581.pdf
Back to top
Profile PM
Dark Java Dude 64
Community Leader
14
Years of Service
User Offline
Joined: 21st Sep 2010
Location: Neither here nor there nor anywhere
Posted: 22nd Mar 2016 15:58
Link
If the knee voltage is what I think it is (the typical voltage drop across a diode), then it should operate more or less at that voltage drop. I hear it can be as high as 3 volts for some LEDs.

Interesting about the supplies! Perhaps you could put an inductor in series with the LEDs to smooth out the spike?

I think for most electronics though, (even integrated circuits due to their larger mass), brief spikes well above current limit are okay.
"By the way, you spelt available wrong"
Back to top
Profile PM Website
Seditious
11
Years of Service
User Offline
Joined: 2nd Aug 2013
Location: France
Posted: 22nd Mar 2016 18:16 Edited at: 22nd Mar 2016 18:33
Link
For these particular diodes it's something like 3-4V at roughly 250ma. I'm just wondering if there's a bit of leeway above the normal operating voltage that can be used as the upper limit when the device is first turned on. If not, I was considering whether something like an inductor would help, or even some resistor/capacitor arrangement to take up some of the inrush current. I wish I were more experienced with these things.

Quote: "I think for most electronics though"


It's a pretty big spike though. If the voltage limit is set to about 9 volts and the diode's forward voltage is about 4 volts, the amount of current that will initially flow will be huge.

Found some more interesting information: http://www.cree.com/~/media/Files/Cree/LED%20Components%20and%20Modules/XLamp/XLamp%20Application%20Notes/XLamp_Elec_Overstress.pdf
Back to top
Profile PM
Dark Java Dude 64
Community Leader
14
Years of Service
User Offline
Joined: 21st Sep 2010
Location: Neither here nor there nor anywhere
Posted: 22nd Mar 2016 19:43
Link
I gotcha. LEDs do seem quite sensitive; I have this old electronics kit with three of them. Each one comes with a little resister conveniently connected to it, but is optional to use. The other day, just for fun, I was doing some really fast blips of unresisted 4.5 volts across one of the LEDs; after doing like four blips, it was completely dead. ..woops! Granted, I've abused other LEDs far worse and had them survive just fine.

Maybe a little low pass T filter would do you well? Should resist that high spike pretty well and let the DC through nicely.

Have you played with the Falstad Circuit simulator? No time to link it in now, but it should come up with a quick Google. Really realistic and flexible, and comes with a neat little scope tool!

When I have time I'll check out that link...
"By the way, you spelt available wrong"
Back to top
Profile PM Website
Seditious
11
Years of Service
User Offline
Joined: 2nd Aug 2013
Location: France
Posted: 22nd Mar 2016 22:12 Edited at: 22nd Mar 2016 22:15
Link
I'm not sure how long the spike lasts before it's corrected, but I think it's long enough that it'd require quite a large cap to take all the current during that period! I wonder what would happen if I provide a large load in parallel for a fraction of a second when power is applied, and then take it away? Oscilloscope plz.

If I remember correctly I have used Falstad quite recently, but I generally use Yenka for simple things and LTSpice for more complex things.
Back to top
Profile PM
Dark Java Dude 64
Community Leader
14
Years of Service
User Offline
Joined: 21st Sep 2010
Location: Neither here nor there nor anywhere
Posted: 23rd Mar 2016 05:23 Edited at: 23rd Mar 2016 05:26
Link
Hmm, I'd assume surely not too long eh? Do you know if your supply's current limit is indeed software controlled? If so, throw an i7 in there and you'll be good to go.

Perhaps it would help to have a look at the input protection multimeters use on their voltage inputs. Metal oxide varistors, MOVs, might actually be exactly what you're looking for. You'd connect one between the supply's terminals, and upon reaching a high enough voltage drop, the MOV would near instantly lower its resistance and conduct current. Upon lowering of the voltage drop, it would quite quickly return to very high resistance.



Dat IV curve tho

EDIT I'm thinking though, your diode may clamp the voltage across the MOV too low for it to activate...
"By the way, you spelt available wrong"
Back to top
Profile PM Website
Yodaman Jer
User Banned
Posted: 25th Mar 2016 12:13
Link
Three days and no posts? What's going on?
Slowly compiling code, one byte at a time.
Follow meh blague for more zany thoughts and possibly offensive programming!
Back to top
Profile
The Slayer
Forum Vice President
15
Years of Service
User Offline
Joined: 9th Nov 2009
Playing: (Hide and) Seek and Destroy on my guitar!
Posted: 25th Mar 2016 14:03
Link
I was searching after my Planetthatstillhastobefoundus, but i still haven't found it.
Nah, just kidding. Was too busy working on my game.
Quote: \"Close those quotes before they start to spread!...too late! Aaaaaagh!!!
Back to top
Profile PM Email
Back to top

Login to post a reply

Server time is: 2024-11-22 20:44:44
Your offset time is: 2024-11-22 20:44:44