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976  Community / Bar Sport / Re: Your latest purchase on: February 09, 2012, 08:53:54 pm

Hey, I see what you mean! ...



I've been gypped! It's an outrage!

Either that, or your meter is a fluke. smiley  (sorry, I had to say it.)
977  Community / Bar Sport / Re: Your latest purchase on: February 09, 2012, 07:35:12 pm
So essentially, it's a piece of wire with some plastic molded over it and a single stripe painted over it.  Ah the good ol' days.
978  Community / Bar Sport / Re: Your latest purchase on: February 09, 2012, 06:32:36 pm
This begs the question Nick, what on earth would you use those for?  Build a sculpture? smiley
979  Community / Website and Forum / Re: Arduino web site very slow on: February 09, 2012, 06:31:11 pm
Yeah, unlike some others, I don't see any DB connection failures, or at least, I have not seen one a quite some time.  I do see many connection problems though, where the browser just sits there, trying to connect to arduino.cc.  It doesn't matter when during the day, I notice it all the time, at the early morning (mountain time) before I leave for the office I would notice it.  at the office, different network, different computer, I still notice it.  When I get home in the evening till the wee hours of the morning, I notice the connection issues.

Like I said, it would work fine for a few minutes, maybe ten at the most, then suddenly start to slow down and stop ... about a minute or two later it would "wake up" again ...
980  Community / Website and Forum / Re: Arduino web site very slow on: February 09, 2012, 05:42:12 pm
Same here ... it works fine for a little bit, then comes to a crawl to a complete stop.  It just sits there trying to contact arduino.cc ...  I see this happen rather often.
981  Community / Bar Sport / Re: Partitioning for speed on: February 09, 2012, 05:36:11 pm
And that would only work once, or if you consistently write the same exact size file back in after deleting another.  Otherwise welcome to the world of fragmentation where you get a single file scattered all over the place.  Single track files go to hell in a hand basket really fast that way.
982  Using Arduino / Microcontrollers / Re: Standalone Arduino on: February 09, 2012, 04:59:04 pm
I always leave the option available.  In other words, I will either lay out the necessary traces so that if I later need them, I can simply solder the components in place, or I will add the minimum parts (like the 10K) and leave the button out.  The pads will remain exposed till I decide to solder a button on.
983  Using Arduino / Project Guidance / Re: Fading three LEDs consecutively over three days. on: February 09, 2012, 04:23:43 pm
Got it.  A future idea then might be to add two levels of reset.  One that does a counter reset, so you're starting back up at 72 hours, and another soft reset which would start where it left off.  In case you accidentally unplug the thing, or the battery died in the middle.  But then you have two options when that happens, do you restart at the same state you were at last, or do you adjust to the elapsed time?  All ideas to work with.
984  Using Arduino / LEDs and Multiplexing / Re: Powering large quantities of LEDs and shift register fun on: February 09, 2012, 02:53:29 pm
Ok then, TY guys. (off to probably break stuff nonetheless)

That's the nature of experimenting.  Though with that also comes the possibility of creating/seeing the magic blue smoke.  I've only seen it once so far. smiley
985  Using Arduino / General Electronics / Re: XLamps - High V & High Amp on: February 09, 2012, 02:19:57 pm
This little guy (NTD5867NLT4G) is a 60V/20A, 39 mOhms N-Ch.  About 20 cents more than the one I currently have in the circuit, which is a 64 mOhms one.

So, what does the RDS value mean or what does it do?
986  Using Arduino / General Electronics / Re: XLamps - High V & High Amp on: February 09, 2012, 01:20:01 pm
Thanks jwatte.  Resistors can be changed to higher wattage of course.  The simple online calculator I used said they would be dissipating 900mW so that's why I picked a 1W resistor.  But I can certainly go higher to a 1.5W perhaps?
987  Using Arduino / Project Guidance / Re: Copter Automation on: February 09, 2012, 05:18:50 am
Datasheets will answer that question: the 5883 is a 3-axis module.  The 6352 is 2-axis.

Rangefinder is used in different ways.  Some folks use it for automated landings, where the vehicle will flare (motors power up to come to a hover) an inch or two above the ground before setting down.  In my case, I use it specifically for turning lights on or off when I fly at night.  At take-off, nav lights and beacons come on when the vehicle is turned on, high intensity LEDs come on when the motors kick in and stay on till the vehicle gets higher than a foot, then they shut off, nav and beacons stay on the whole time.  For landings, at about a foot off of the ground, I turn on some high intensity LEDs to see what the vehicle is landing on.   During the day, the high intensity LEDs don't turn on, and for now the rangefinder isn't used for anything else.  Eventually I will add automated landing but that's so far down the list ...

No video of it because the video camera is usually strapped to the vehicle's video platform.  The only times it's not on there is when I'm testing new code and I take the whole platform off of the motor assembly and just fly that.
988  Using Arduino / General Electronics / Re: XLamps - High V & High Amp on: February 09, 2012, 04:21:41 am
Yeah, I'm starting to realize no matter what, ultimately I'm looking at spending some serious dough.  Ok, slightly off track ... I'm putting these LEDs on the back burner for the time being.  The next set of testers I have are closer to voltages we're more used to fiddling with, 3V forward voltage, 350mA.

If I get a driver capable of 9V/3.3A (constant voltage), I can then power an Arduino, while also providing power to the LEDs themselves (so they don't pull current from the Arduino pin).  I'll use a resistor to control the current to the LED, and a mosfet to turn it on and off with the Arduino.  Yes?

Two questions:

- If I want to drive the LEDs at 300mA, and I want to have a pair per "string", would the attached schematic work, both as a single pair, as well as an expanded set of pairs?

- Can I use a PWM signal to the mosfet to fade the LEDs?  Any particular detail I need to be aware of when choosing a mosfet (other than voltage and amount of current)?

(edited to add the part number for the mosfet)
989  Community / Bar Sport / Re: Partitioning for speed on: February 09, 2012, 03:28:51 am
The point of partitioning isn't to protect data (although it can do this; recovery, though, may end up being expensive) - partitioning is useful in the instance where you want to keep your data (and possibly applications) separate from your system install; if you ever wanted to wipe your system and start fresh, you could just wipe the partition and start over.

Yes and no.  It depends on the operating system.  Under Win7, you will quickly discover that your files and folders are not accessible because the UUID is different.  There are ways to fix that, but it's still a pain to have to deal with it.  Been there, had to deal with it ... decided it wasn't worth and bought a $100 2TB drive (t'was on special.)
990  Community / Bar Sport / Re: Partitioning for speed on: February 08, 2012, 11:53:06 pm
I thought the disk slows down as the read/write head moves outwards to maintain a constant read speed. But if the spool was a constant speed the read times would be shorter on the outer parts of the platter.

This is only true of CD/DVD drives.  Magnetic drives spin at a constant speed.  Data is written from the center out (which is the same for CD/DVD).

And while read times are shorter on the outside ring, the lookup table is still on the inner circles, so the head will be traveling back and forth anyway.  When measured from the moment the request comes in to the time the data is send back, it's actually shorter to read the inner circles than it is to read the outside circles because the reading head isn't traveling that far.  However, that time difference is so freaking miniscule, it's not worth sweating over it.

As far as partitioning goes, the real reason here is why?  Consider that the same reading head has to travel across the same platter, regardless of what partition the data is in.  In some ways, partitioning a drive slows it down because the reading head is now traveling back and forth several times.  And partitioning really doesn't gain you any advantage anymore.  If the drive is going to fail, it's going to fail.  No amount of partitions will save your data.  Drives are cheap, get a second one.  Or if you're like me, a 7th one.
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