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961  Using Arduino / Project Guidance / Re: analog input alters voltage... doesn't read properly on: May 03, 2013, 07:42:58 am
Hopefully this solves the issues I was having initially w/ the analog input voltage being skewed once plugged into my bike.

The analog trouble's solution will be changing the source/"Vin" to 9V.
962  Using Arduino / Project Guidance / Re: analog input alters voltage... doesn't read properly on: May 02, 2013, 08:23:23 pm
Get 100Ω (brown-black-brown) resistors - or my head will explode.

"How can I test that the resistors are working?"
The only way to KNOW is with a voltmeter.
+5 to CA, one lead of one resistor to any segment (cathode) with the other lead to Gnd.
There will be approx 1.5V across that resistor.

If the "spare" LED is a blue LED, you can use that.
If the "spare" LED is another colour then it will have a different forward voltage and skew the results.
963  Using Arduino / General Electronics / Re: Can my Arduino burn up if my voltage regulator overheats? on: May 02, 2013, 07:59:34 pm
I am using something like the LM317.  Its a three pin 9V regulator.  I think its a LM7809CT.  I'm not 100% sure though.  I have it hooked up through the input jack.  My arduino originally came with a 9V battery pack to power the arduino so could someone explain to me why that would work but the voltage regulator could possibly burn up the arduino???

In theory, it ought to be OK.
But statements like "I am using something like the LM317.  Its a three pin 9V regulator.  I think its a LM7809CT.  I'm not 100% sure though" don't make me want to leap up and shout, "Yes, Do It!" 
964  Using Arduino / Project Guidance / Re: analog input alters voltage... doesn't read properly on: May 02, 2013, 07:36:14 pm
You have to connect the CA to +5, and NO, doing so will NOT "overvolt and damage them" - unless you don't use a resistor!
When the LED is ON it's its forward voltage is "3.5V"
So, the balance of the 5V will be across the resistor - 1.5V
That 1.5V across the resistor will determine the LED current
1.5V / 100Ω = 15mA

> > > I spelled all of that out in Reply#37.  You're not reading.


965  Using Arduino / Project Guidance / Re: analog input alters voltage... doesn't read properly on: May 02, 2013, 06:29:34 pm
Grumpy_Mike,
pcguru has an Uno (it's there in his big darned PNG), there's 5V available on it - which I noted in my Reply_#37: "Anyway, you should have the CA wired to +5."
He was putting the 7-segment's CA to 3V in the belief, howbeit mistaken, that that would obviate any need for resistors.

966  Using Arduino / Project Guidance / Re: analog input alters voltage... doesn't read properly on: May 02, 2013, 07:58:18 am
So you project needs to be even more complex than just adding a resistor, you need a boost constant current LED driver.

Absurd.
967  Using Arduino / LEDs and Multiplexing / Re: pls help me on my skitch on: May 01, 2013, 08:31:49 pm
Not sure what you really want.
You can look up "Port Manipulation" if you want to do them all at once.
The Arduino thing to do, though, is to write them in succession.

Code:
int ledDelay = 50; // delay by 50ms
byte redPin1 = 6
byte redPin2 = 7;
byte redPin3 = 8;
byte redPin4 = 9;
byte bluePin1 = 10;
byte bluePin2 = 11;
byte bluePin3 = 12;
byte bluePin4 = 13;


void setup() {
pinMode(redPin1, OUTPUT);
pinMode(redPin2, OUTPUT);
pinMode(redPin3, OUTPUT);
pinMode(redPin4, OUTPUT);
pinMode(bluePin1, OUTPUT);
pinMode(bluePin2, OUTPUT);
pinMode(bluePin3, OUTPUT);
pinMode(bluePin4, OUTPUT);
}

void loop()
{
  digitalWrite(redPin1, HIGH);
  digitalWrite(redPin2, HIGH);
  digitalWrite(redPin3, HIGH);
  digitalWrite(redPin4, HIGH);
  delay(ledDelay); // wait 50 ms

  digitalWrite(redPin1, LOW);
  digitalWrite(redPin2, LOW);
  digitalWrite(redPin3, LOW);
  digitalWrite(redPin4, LOW);
  delay(ledDelay);
}

If you want to turn on several LEDs, the same LEDs, with one pin, then there are ways to do that (time to get a transistor.)
968  Using Arduino / Installation & Troubleshooting / Re: no Rx/Tx activity on: May 01, 2013, 08:15:52 pm

http://arduino.cc/en/Main/ArduinoBoardMega2560
http://atmega32-avr.com/wp-content/uploads/2012/06/arduino_mega_2560_schematic.gif

Maybe there's lack of continuity with the USB connector (broken solder, bad contacts)?
[Running out of ideas...]

I don't have any info on re-flashing the 16U2, if that's required.
(Sorry.)
969  Using Arduino / Installation & Troubleshooting / Re: Arduino UNO overheating when ethernet shield is connected on: May 01, 2013, 07:58:29 pm
How about reducing the input voltage to 9V (i.e. an alternate battery pack or try using a lab suppply set to 9V to try it out)?
970  Using Arduino / Project Guidance / Re: analog input alters voltage... doesn't read properly on: May 01, 2013, 06:27:58 pm
Two things-
What is meant by "mux'ing"?

Yes the LEDS are blue- I am using this: https://www.sparkfun.com/products/9191
-These are running at 3.3v- but am I understanding now that they could pull 3.5 somehow?

"Mux'ing", short for multiplexing.  If you can have two or more segments on at once, then they aren't mux'ed.  If your sketch strobed quickly through them repeatedly, only one possibly on at any time, then they'd be mux'ed.
Anyway, you should have the CA wired to +5.  If you use a 100Ω resistor for each segment they'll pull around 15mA [as (5-3.5) / 100 = 0.015], with 220Ω resistors they'll pull 6mA [as (5-3.5) / 220 = 0.006].  100Ω and 220Ω are "standard value" resistors.  

> > > [I'm sure you get it, but with CA, the LED is on when its corresponding Arduino pin gets a digitalWrite LOW.]
971  Using Arduino / Installation & Troubleshooting / Re: Killed Arduino by following BlinkingLED tutorial from arduino.cc on: May 01, 2013, 01:53:10 pm
Now we just need that page to correctly say:
"Most Arduino do not boards already have an LED attached to pin 13 on the board itself."

Put that way? 
I hope not.
972  Using Arduino / Installation & Troubleshooting / Re: no Rx/Tx activity on: May 01, 2013, 01:49:26 pm
Loop-back test dos not work.
No Rx/Tx Led activity.

That's a telling thing.

When Flip works, tehere is Rx/Tx activity

What is "Flip"?

Is this a genuine Arduino "Mega" or is it a "clone"?
Is it New or did you get it from somebody else (Used)?
973  Using Arduino / General Electronics / Re: Wheatstone bridge on: May 01, 2013, 01:45:00 pm
As it is or was for a sketch, I figured I ought to stay inside that machine paradigm.
I probably should have posted a pic of my solution.
Anyway.

Quote
"I apologize if you are very troublesome,..."
You know me only too well.
974  Using Arduino / General Electronics / Re: Wheatstone bridge on: May 01, 2013, 08:04:59 am
As far as having "too many parentheses"... I forgot to insert that darned smiley!

Well, I think that I rearranged the expression for RG right.
If that doesn't produce the desired result then what is the question (again)?

I did not know that we can use { } and [ ], too.  (I know that we do in Algebra class, but, anyway.)
975  Using Arduino / General Electronics / Re: Wheatstone bridge on: April 30, 2013, 10:57:52 pm
An expression can't have too many parentheses, can it?
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