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16  Using Arduino / General Electronics / Re: LM317 not working as expected on: March 23, 2013, 07:18:40 pm
Lefty, I'm probably definitely going overboard, 'cause I don't really know what I'm doing. Now, keeping that in mind, what exactly do you mean by two series diodes? Two diodes in series? What kind of diode? Why are two diodes better than one voltage regulator (if it worked)?

Yeah, my sketch actually has analogWrite(9,~255); but for simplicity I left that tid-bit out, and as usual, I had to explain it anyway.. so much for simplicity. I should stop taking shortcuts...


Afremont, Hmmm...maybe? I went from Vout to R1k to multimeter to ground.
17  Using Arduino / Project Guidance / Re: Doubling PWM voltage (For LED Driver) on: March 23, 2013, 07:06:50 pm
Maybe I don't know what I'm talking about...

In the circuit I'm using for the voltage regulator, http://imgur.com/cDZIY9a , Vout goes through a resistor to ground, and to measure voltage I've been putting the leads of my multimeter to Vout and Ground.

I've had Vout over 10 volts at some points.
18  Using Arduino / Project Guidance / Re: Doubling PWM voltage (For LED Driver) on: March 23, 2013, 06:54:31 pm
Was just looking back through this thread, and noticed you said not to feed more than 5V back into the arduino board.

Does that include the ground? I've been using the ground on the board during my experiments, and been feeding between 2V and 11.7V into the ground on the arduino.

19  Using Arduino / General Electronics / Re: LM317 not working as expected on: March 23, 2013, 06:47:03 pm
You ninja'd me, lefty. I'm going to use it to do the dimming function of 2 different meanwell led drivers, ELN60-48P and ELN60-27P
(Making separate circuits for each, so just one driver for this example)

Here's a link to my first post, which goes into greater detail about what I'm doing. http://arduino.cc/forum/index.php/topic,155564.0.html#msg1166302

 Thanks for taking a look!
20  Using Arduino / General Electronics / Re: LM317 not working as expected on: March 23, 2013, 06:44:11 pm
Adding a 1k resistor to the output didn't change anything, but thanks for the tip, I'll keep that in mind.

I found where it shows that I need at least a 3V difference, but boy was that worded weirdly. Maybe it's in English somewhere else on the sheet.

Did a little research, and I started looking for a "low-dropout" voltage regulator. So far I'm not finding one to suit my needs, but i'll keep looking.

Do you have a recommendation off the top of your head?
21  Using Arduino / General Electronics / LM317 not working as expected on: March 23, 2013, 05:16:04 pm
Hardware noob here...

I have a 12V regulated power supply feeding an Arduino uno.

My sketch is just analogWrite(9,255) which puts 5V out of pin 9.

Pin 9 runs through a circuit with a 2n2222 to increase the voltage up to Vin. (http://imgur.com/xB0H67T is the circuit)

So, I have 11.7V coming into the breadboard I'm doing now. The point of my breadboard is to lower that 11.7V to 10V.

I send that 11.7 to the LM317, using this diagram; http://imgur.com/cDZIY9a

Should be Vout=1.25V(1+(R2/R1))

With R1=1K and R2=1K I would expect 1.25*(1+1)=2.5V but I actually get 2.84V. That could be my multimeter, something weird in the circuit, I dono, I don't think that's too bad.

Now, replacing R2 with a 6.8K resistor, I would expect 1.25*(1+6.8 )=9.75V.  I actually get about 7V

Being the noob that I am, I just kept plugging bigger resistors in for R2 until I got to 100K. With a 100K for R2, I get Vout=9.5V

At that point I figured it was best to stop trying to blow things up, and just ask here.


Any advice?
Thanks for reading!

22  Using Arduino / Project Guidance / Re: Doubling PWM voltage (For LED Driver) on: March 23, 2013, 02:16:10 pm
Yeah, I definitly won't be doing anything without consent from this forum, haha. It should be a ways off, I'll crass that bridge when i come to it. In other news, after only slight frustration, I got my RTC working!

Time to breadboard this voltage limiting/boosting thingy!
23  Using Arduino / Project Guidance / Re: Wave/mp3player+15 led scanner on a 328p-pu? on: March 22, 2013, 08:56:39 am
I'm no pro, but maybe I can help out a bit anyway. Do you already have a board? I think the arduino mini should be able to do all of this, I don't have one though, so look into it and see what it's capable of.

Do you have an idea of what you're doing, or no arduino experience at all? You should start with the tutorials on this site about LEDs. Once you've done a few of those you should be able to figure out how to make this happen fairly easily.

I know that you can do a sound, but I've never done it, so I can't help you out there.


EDIT: Just saw the 328p-pu. Disregard post, I have no idea.
24  Using Arduino / Project Guidance / Re: Doubling PWM voltage (For LED Driver) on: March 22, 2013, 08:52:16 am
Yeah, I think that the PWM drivers are the simplest set-up, that's why I'm starting out with them. Arduino puts out a PWM already, what could be easier? I'm aware of the fact that they're physically different drivers, but thanks for the tip.

I'm definitely worried about improvising (adding an override) because I'm not knowledgeable enough to do that. I'm sure a pot between the arduino and the driver would be fine, but I'd have to think hard about a switch and pot, probably another power source, to completely override it.

Thanks a bunch for sticking this out, and giving me such good advice. Much appreciated.

Told my girlfriend she won't be seeing me much this weekend. Will report back!

25  Using Arduino / Project Guidance / Re: Doubling PWM voltage (For LED Driver) on: March 21, 2013, 01:21:18 pm
I was looking at the data sheet later, and maybe it was an updated version, but lower on the sheet it goes into more detail about the PWM and it does call out 10v on the PWM.

Quite a few people claimed that running from the arduino board with a 5v PWM halved the output of the driver, and I was really confused about it. I thought (and still do think, but this made me question myself for a little) that PWM was on or off, digital... output is determined by the time between on and off. (skimming your link, the gif seems to indicate that it's actually the difference between time on and time off, but the principal is the same... I still have to assume that half of this "electronics" stuff is black magic)

Reading further, I saw a lot of people saying 'that's not how PWM works' but there were enough people saying that it happened to them that I think it's true. I don't know if they were getting half power, and it was going from on to off, or what, people with the problem didn't go into much detail, they just sailed right by it to "need to boost the voltage." I dono, something must be going on there. Some people had thoughts that the circuitry used some kind of work-around, maybe to lower costs for both models, and that's where the unexpected results came from, sounds plausible.

I'll keep trying. smiley-wink

EDIT: Yeah, I'm going with the PWM drivers for now. I think some day I might try switching them to analog drivers, or maybe on my next build. I'm interested in trying it out. I think they're a little more useful, 'cause you can override (With a switch, or modify in line) the arduino's signal with a pot. Also, they cut off at 5% power, whereas the PWM ones cut off at 15%. PWM just seems a lot easier for now though.
26  Using Arduino / Project Guidance / Re: Doubling PWM voltage (For LED Driver) on: March 21, 2013, 10:59:49 am
Hmm, it's not showing. Maybe I need more posts or something.


EDIT:

I'm on the right track here. Gonna head to the local electronics shop after work (Hopefully they have what I need 'cause god knows da shak won't) to pick some transistors, 10v (and variable, why not) regulators, and a 12v power supply.. and I guess some kinda board. Maybe some wire... and new tips...

I'm still interested in using some kind of IC to make this project smaller, so if anyone has any guidance, I'm still all ears.
27  Using Arduino / Project Guidance / Re: Doubling PWM voltage (For LED Driver) on: March 21, 2013, 09:26:35 am
You're sure the posted resistors are correct? The poster says they might not be.

Okay, I thought that the data sheet did indicate 10V (I'm not familliar with drivers, assumed that since the 10V is the only one listed, that it was assumed that PWM was also 10V.) I would think that something taking PWM shouldn't need a whole 10V, but I dono. Everyone online seems to agree that it does need 10V for the PWM. I guess with a 5V PWM it maxes at half brightness (Which doesn't seem to make sense to me, PWM is digital, right? Others who are more knowledgeable than me also don't understand, and I guess it has something to do with the driver not being 'true PWM' I dono how that works.) I should probably pick up a driver anway, and start testing. Maybe everyone else is just confused, and the 5V works fine. Thanks for the prod!

So I get a 12V supply, the Vin pin will put out 11.3 ideally? And a 10V regulator is a magical thing that will drop that to 10? Sounds beautiful. now to go research how a regulator works.

Thanks for the reply!

(EDIT: How do you give Karma?)
28  Using Arduino / Project Guidance / Doubling PWM voltage (For LED Driver) on: March 21, 2013, 08:46:45 am
I know this is covered other places, believe me, I've been reading for hours, but I guess i'm just dumb.

I need to control dimming on 3 led drivers. 2 Mean Well ELN-60-27P and 1 Mean Well ELN-60-48P (DATASHEET: http://www.meanwell.com/search/eln-60/default.htm) I want to use the fewest components possible, of course. I have an Arduino UNO R2.

The thread that I understand best is this one(http://arduino.cc/forum/index.php?topic=20632.0) from a few years ago, but I didn't wanna raise the dead to ask questions there. Post #8 has a diagram that I think I understand, and I could use that, but I think there's a better solution further down.

So, for starters, on post 8; how do I figure out what resistors to use?
How do I figure out which pins on the NPN go to which places? (Really, I think that's shown, I really could also use a good resource on the meaning of the symbols)

Further down, the ULN2801/2/3/4/5, ULN2001/2/3/4 chips are recommended. I've been looking at their spec sheets, but that's not helping me figure out how to wire them. Can anyone give me some insight, or point me in the right direction? (Also, just for now, can someone tell me which ones to buy? I want to order them ASAP, even though I dono what they even are yet)

I think i'll build and test the first solution, and once that's working, also build and test the second solution. I have a bit of time before I'm ready to cough up the $300 for the other parts of the build. (Which is REALLY cheap, by the way, looking through old threads, people were spending $2000 doing the same thing I'm doing now only a few years ago... I'm sidetracking...) If I power the Arduino with a 10v, does that 10v come out of the board somewhere (Vin?)? If I can't find a good 10v supply (seems they're hard to come across) and i need to use 12v, how would I work that out? I guess I really don't know how to power this, and I could ask a billion questions right here, but I'm sure one of you geniuses just knows the answer.

I know this is a lot for my first post, but I'd be really thankful for some help. I've been having a ton of fun messing with this board ofr the past few days, it's so easy to use, and there's so much documentation. Thanks a ton!



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