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46  Using Arduino / Installation & Troubleshooting / Re: Connecting Arduino Nano via USB [MAC] on: March 11, 2014, 02:18:39 pm
The "..." Part of the device name is the critical section.  Uno will show up as "usbmodem" and FTDI based devices will show up as "usbserial".

Assuming a genuine uno, there is no common USB hardware between a nano and Uno.   So one working really means nothing for the other.  They used different implementations.

If I your uno is connected and you see a "usbserial" device, either it is not the Uno or it is not a genuine uno.
47  Using Arduino / General Electronics / Re: What component is this, Arduino Nano v3 on: March 11, 2014, 02:06:16 pm
The diode provides a method to select either the on board 5v regulator or 5v coming from USB.  (Well it's more simplified than that.  If a voltage is present on both, it prevents the on board 5v from conducting to USB.)

One comment would be, if you don't know what smoked it the first time, it stands to reason you will likely make the same mistake again.

Second comment would be, never hook up an external 5v and USB at the same time, until you replace the diode.
48  Using Arduino / General Electronics / Re: What component is this, Arduino Nano v3 on: March 11, 2014, 10:30:48 am
If it is a true V3, using the photo from the product page:  and the EAGLE files available there, it does look like the diode majenko identified.

Probably blown by too much current flowing or reverse voltage?
49  Using Arduino / General Electronics / Re: guide of different circuits, anyone? on: March 11, 2014, 10:21:59 am
Too bad those don't have the suits/numbers, etc. to function as regular playing cards.  I'd buy a deck if they did.

Ace of Blue would probably have to be a 555 circuit?  Or maybe an astable multivibrator?  Dunno.   
They aren't the same size as playing cards and there aren't 50 (or 52) of them.

I like them better as trading cards.  They remind me of baseball cards, not poker cards.
50  Using Arduino / Installation & Troubleshooting / Re: 'serial port already in use'... on: March 09, 2014, 10:34:01 pm

Do the first step and see what else is using the serial port when it is claimed to be "in use."

OSX doesn't report it is in use, unless something claims it.
51  Using Arduino / Networking, Protocols, and Devices / Re: Cannot find Bluetooth Connection on Nexus 4 on: March 09, 2014, 10:31:44 pm
Probably need more details.  Your subject line mentions "Nexus 4", what's that have to do with anything?  What do you mean by "cannot find the connection"?  By where/what?
52  Using Arduino / General Electronics / Re: Electronics Book Suggestions? on: March 09, 2014, 10:26:52 pm
I'm having trouble with the electronics end of things.
Check out my video tutorials.

They're intended to sit between incomplete tutorials and deep-dive books.

how to I calculate the correct value for a resistor for a given circuit, or whether or not I need one?
The reason for a resistor is seemingly simple however the uses are extremely wide ranging.  Sometimes it's about pull to a certain voltage, sometimes it is about dividing, sometimes it is about limiting current.  You aren't going to find an all-in-one guide on how and why you use resistors.  It's better to understand how they work, so you can apply them when necessary.

how to I calculate the correct value for a resistor  getting the Arduino board to control 2 or 3 motors, and or stepper motors. Since the board doesn't put out enough amps to do so I imagine that I would need to either use the board to control some relays or transistors. Or perhaps better yet, use an add-on motor control board?
You already answered your own question on this one:  additional hardware

how to I calculate the correct value for a resistor 
3) getting the Arduino to control 20 or so LEDs. Answer probably similar to above?
Well similar to above if "additional hardware" applies.  It entirely depends on what you want to do with those LEDs to what you need to do.  Do you want individual control?  Do you want them all on at the same time?  Are you trying to make a flashlight?  A scrolling sign?  Lots of depends on that one.

General questions are good.  Project-specific questions are far better.
53  Using Arduino / General Electronics / Re: Arduino mega 2560 power input? on: March 07, 2014, 09:54:54 am
so Im going to use separate 2 batteries in series (24v)  with 7805 regulator. will it solve my problem ?
No!  The bigger the difference between the regulator's Input voltage and Output voltage, the hotter it will run!

54  Using Arduino / General Electronics / Re: Arduino and Electrical Engineering on: March 07, 2014, 09:30:10 am
Which is very unusual for kids from my generation; I'm 21.
You aren't alone.   The maker movement is full of people your (our?) age doing exactly what you are.  You should try to find a nearby Hackerspace or attend a MakerFaire to meet others like minded.  Or even sit in Adafruit's "Show and Tell" Google Hangout.

I found books on Arduino, electronics, and electrical engineering but I didn't understand a word they said, so I figured I'd ask people who had "been there and done that."
First, one pass will never be enough.  You'll need to do some reading, some experimenting, then some reading again.

Also, don't be discouraged if the materials are "over your head" (today).  Many engineering tutorials are written by engineers.  Who often believe the only way to learn something is how they learned it.  You know, understand the molecular theory of how transistors work, before you use it to turn on a relay.  Which doesn't work for everyone.

You might find my series of electronics videos interesting:  I try to take a more high-level approach with the intent to at least arm you with the right words and phrases to do deeper searches.  I also try to add "more in depth" stuff on the show notes pages (linked in the descriptions).

Try not to be so rude.
Sadly there are a couple of members of the forum who think belittling new (to Arduino, Programming, and Electronics) users is a requirement of the forum.  This is sad because that small number has convinced a larger number it's okay to act that way on occasion.
55  Using Arduino / General Electronics / Re: guide of different circuits, anyone? on: March 07, 2014, 09:21:37 am
These circuit pattern cards are a nice set of basic circuits.
56  Using Arduino / Project Guidance / Re: Serial Communication on: February 26, 2014, 08:24:03 am
One post you mention using only print() the code with float is println().

Did you change two things at once?  Because you really don't want to be using float.
57  Using Arduino / Programming Questions / Re: Advanced strings in HTML on: February 25, 2014, 06:55:59 am
I'm thinking of using a for loop, but I need to know:
That's a simplistic approach to solving the problem.  I'm glad you're thinking of the direction "what do I need to know?"  However, "using a for loop" is a little too deep dive to be useful.  You're going to need a number of skills, including basic control structures like for loops.

How to append strings, how to interpret them, etc.
Yes, you need to spend time on how C handles strings.  I would do this separate of your HTML work.  Learn how to send and receive characters over serial and then append them to strings.   Hint:  you do *not* want to use the Arduino "String" object.

Learn how C++ handles strings.  For example, == doesn't work on a string.

I would love Python's for loop right now
I'm really not sure what you mean by this.  All programming languages have loop structures.  That's just a basic component of the language.
58  Using Arduino / General Electronics / Re: atmega328 pin20 on: February 25, 2014, 06:48:48 am
From the ATmega328 datasheet.

Section 1.1.7
AVCC is the supply voltage pin for the A/D Converter, PC3:0, and ADC7:6. It should be externally connected to VCC, even if the ADC is not used. If the ADC is used, it should be connected to VCC through a low-pass filter. Note that PC6...4 use digital supply voltage, VCC.

Section 24.2
The ADC has a separate analog supply voltage pin, AVCC. AVCC must not differ more than ±0.3V from VCC. See the paragraph ”ADC Noise Canceler” on page 248 on how to connect this pin.
59  Using Arduino / Installation & Troubleshooting / Re: Serial port already in use_error message on: February 24, 2014, 05:03:54 pm
avrdude: stk500_getsync(): not in sync: resp=0x00
Is a generic error which is probably caused by 100 things (okay maybe a dozen, but whatever).  Nosingle definitive response can be given to solve it.
60  Using Arduino / General Electronics / Re: Arduino Nano + ENC28J60 wiring on: February 24, 2014, 03:47:01 pm
there's also this diagram from the datasheet;

For a generic application note, of course they will suggest using a level shifter.

However in this specific case with the ATmega328, a shifter is not necessary.  The threshold for a HIGH is sufficient for both 3V3 and 5V logic.
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