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46  Using Arduino / Programming Questions / Re: Visual C# Serial Communication Question on: March 19, 2014, 04:07:38 pm
I got the code to work with the serial monitor from the arduino software which makes no since to me.
Serial is an asynchronous communication method.  So you can't expect characters to arrive within a given time frame.

The serial monitor is sending characters fast enough that the serial buffer gets both characters before you check it.  In the case of the C# program, it must not be sending the characters fast enough so that your code executes, and only sees one character at a time.

There are two solutions:
1.  Always send the same number of characters and only check what's in the serial buffer when that many characters are received.  (E.g. Serial.Available() > 2).  of course, you have to be careful and only read two characters at a time (what if there are 4?)

2.  Use a delimiter like NL or CR to let your program know when a string is done being received.  In that case you process the characters on at a time until the delimiter comes in.
47  Using Arduino / Programming Questions / Re: class String has no memeber named 'toFloat' on: March 19, 2014, 03:02:33 pm
Any Ideas????
The String object doesn't have a toFloat() method.

http://arduino.cc/en/Reference/StringObject#.Uyn6Fa1dUz0
48  Using Arduino / Programming Questions / Re: Problem with Arduino mega 2560 serial port on: March 18, 2014, 09:51:23 am
Are you changing the to the appropriate com port in Processing?
49  Using Arduino / Installation & Troubleshooting / Re: how join dialout group? on: March 13, 2014, 05:07:09 pm
sudo gpasswd -a edilon dialout
50  Using Arduino / Programming Questions / Re: Problem with Arduino mega 2560 serial port on: March 13, 2014, 05:06:26 pm
Thank you... The program is  long...
Without code is going to be extremely difficult to help you debug a problem with your code.
51  Using Arduino / General Electronics / Re: Are these oscilloscope readings right? on: March 11, 2014, 11:11:00 pm
If any other newbie like me is reading this and considering buying an oscilloscope,
If I could only have one piece of test equipment in a lab, it would be a two channel scope.  If you get desperate enough, you can even measure current with it (using a small shunt resistor.)
52  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.
53  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.
54  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:  http://arduino.cc/en/uploads/Main/ArduinoNanoBack_3_lg.jpg  and the EAGLE files available there, it does look like the diode majenko identified.



Probably blown by too much current flowing or reverse voltage?
55  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.
56  Using Arduino / Installation & Troubleshooting / Re: 'serial port already in use'... on: March 09, 2014, 10:34:01 pm
http://www.baldengineer.com/blog/2012/10/08/arduino-fixing-serial-port-in-use/

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.
57  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?
58  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.  http://youtube.com/addohms

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.
59  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!

60  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:  http://www.youtube.com/addohms.  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.
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