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2341  Community / Bar Sport / Re: People hate resistors for their LEDs on: January 21, 2013, 10:30:15 am
EVP; I bookmarked that page twice and Karma'd you once.

Crossroads, I never tried but can I get Vf using a meter on the led?

One way I can get at least close is get the led in bright light and see the V it generates.
2342  Using Arduino / Programming Questions / Re: GPS Coordinates and Float precision on: January 21, 2013, 04:44:17 am
You could use 64-bit long long to store/manipulate coordinates down to the meter.

2343  Using Arduino / Programming Questions / Re: A quick reference please sei() on: January 21, 2013, 04:39:53 am
reference from AVR LibC

http://www.nongnu.org/avr-libc/user-manual/group__avr__interrupts.html
Quote
#define sei    (       )    

Enables interrupts by setting the global interrupt mask. This function actually compiles into a single line of assembly, so there is no function call overhead. However, the macro also implies a memory barrier which can cause additional loss of optimization.

In order to implement atomic access to multi-byte objects, consider using the macros from <util/atomic.h>, rather than implementing them manually with cli() and sei().
2344  Community / Bar Sport / Re: Open-source government on: January 21, 2013, 04:27:32 am
Just vote greed and wonder why you're getting poorer.


2345  Community / Bar Sport / Re: People hate resistors for their LEDs on: January 21, 2013, 04:14:04 am
I had a UV led on a pot and made the mistake of turning the pot too low. Weird smell.

Hardest part for me is trying to remember how to determine the resistor value, which I have to go search on to re-check even if I do think I remember just to be sure which I'm not. So I aim high as I don't like leds hurt-my-eyes bright anyway.
I run 340+ ohms at 5V with standard 5mm reds for indoor use. Maybe they'll live longer, certainly they use less power.

2346  Community / Bar Sport / Re: Aaron Swartz sucide on: January 21, 2013, 03:39:06 am
Swartz tweaked powerful noses. And who knows what he might do next?

Loose cannon and all that, threat to the comfort of his betters, someone get a hound on his tail, grumble-grumble where's my tea? And my oxy?

2347  Community / Bar Sport / Re: So what (grin) resistor should i use for this LED then? :D on: January 21, 2013, 03:31:15 am
There's voltage regulators and there's current regulators.

Quote
Characterizing the Thermal Resistance Coefficient of LEDs
http://www.lrc.rpi.edu/programs/solidstate/cr_thermalresistance.asp

Quote
Do LED bubls weaken/lose brightness over time?
http://www.candlepowerforums.com/vb/showthread.php?132057-Do-LED-bubls-weaken-lose-brightness-over-time

But why ask people who have spent more than a little time actually checking these things when you can simply misinterpret a datasheet?

Hmmmm, led brightness drops off over the lifetime (50,000 - 80,000 hours?) by perhaps 30% before it dies. Then the loss is 100%.

So getting old sucks for leds too.
2348  Using Arduino / Programming Questions / Re: Reading values from an array on: January 20, 2013, 06:17:15 pm
ooops! you found a bug, LOL!

Maybe I was wrong about being wrong....

highest: 16 8 4 2 1 -- exits on zero
level: 5 4 3 2 1 -- and if 0 then none match

And all the pins can be read in ... if I have this correct, maybe 1 or 2 cycles.

2349  Community / Bar Sport / Re: Aaron Swartz sucide on: January 20, 2013, 05:30:11 pm
There is no correcting those people. None whatsoever. They live in fact-proof bubbles.
2350  Using Arduino / Programming Questions / Re: Reading values from an array on: January 20, 2013, 05:26:29 pm
ooops! you found a bug, LOL!

It needs a bit more in case they're all zero. Maybe I spelled that kat?

2351  Using Arduino / Programming Questions / Re: what input pin is it using? on: January 20, 2013, 05:23:27 pm
I would use an Arduino to read 1 sensor on 1 pin to maybe fill an array at the tap of a button with timestamps showing state change times **just to see if I get useful data**.

If I didn't have a laptop to save those to then maybe I'd have them go to SD or EEPROM for later retrieval. Perhaps I'd think of a way to get speedometer data in there or just write that on paper.

You could have it read a pin and light up one of a row of leds to show data within different ranges. You don't have to be exact, just look for a suitable match to what you need.

What have you tested already? Do you need more complete or better data?
What can I say? I still don't know what this is for anyway.
2352  Using Arduino / Programming Questions / Re: Reading values from an array on: January 20, 2013, 04:53:57 pm
untested, and I probably spell cat wrong too

Code:
// Say this array contains {1, 0, 0, 1, 0}

byte bitArray = 0b01001; // low order bit is on the right here

byte highest = 16;
byte level = 5;

while ( highest ) // same as while ( highest > 0 )
{
  if ( bitArray >= highest )  break; // exits the loop, your answer is in 'level'
  highest /= 2;
  level--;
}

Serial.print( "The highest is #" );
Serial.println( level, DEC );


Choose your pins with care and you could load bitArray with a single Port read.
2353  Using Arduino / Programming Questions / Re: math problem on: January 20, 2013, 04:42:59 pm
Is HSL floating point?

2354  Using Arduino / Programming Questions / Re: what input pin is it using? on: January 20, 2013, 04:34:42 pm
That first link --- anyone who pays that much for a Hall sensor has more money than knowledge. Holy cow, what a ripoff!

You have sensors in place though I'm not clear what you want the data for... is it to know speed?

Again, I would gather data and see which is suitable before even starting to design a final package.
2355  Community / Bar Sport / Re: Aaron Swartz sucide on: January 20, 2013, 04:26:44 pm
It has everything to do with presumption of innocence; you probably don't understand what that actually means.

Good luck with that. Since the Police State took over, innocent until proven guilty doesn't happen until you hit court and they're working on fixing that too.

Get deep in tard-con country and you'll hear gems like "He didn't EARN his rights!". That gets Amens. Yup, and they're all patriots too. Here's to the Evangelist States of America, everyone else Howdy Now Git!

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