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4186  Using Arduino / Programming Questions / Re: DS1307 RTC library on: November 28, 2011, 10:51:03 am
" int minval = (now.minute(), DEC);"

This doesn't make sense.  The argument ", DEC" tells Serial.println what format to print the number as (DECimal, HEXadecimal, OCTal, etc).

Should be:
int minval = now.minute();
4187  Using Arduino / Programming Questions / Re: DS1307 RTC library on: November 28, 2011, 10:09:04 am
i looked at the library from here, but i can't find much documentation about it
You really shouldn't need much in the way of documentation.  The examples provided with the library and on Ada's tutorial page tell you how to set the time and read the time.  That's all you need to do.

Don't overcomplicate your design by trying to set alarms or anything.  Just write your code to check what time it is and if you should be turning lights on or off. 
4188  Using Arduino / Programming Questions / Re: Limits on size of String and using indexOf() ? on: November 27, 2011, 02:27:22 pm
Which Arduino board / ATmel processor are you using?

where data is the incoming character.  This creates a String of typically about 200 characters.
Keep in mind that when a String object is concatenated, a new buffer the size of the original string plus 1 is created.  Then the new result is copied into the original buffer.  This means you are using 2x the storage required during the operation.  So if you have 200 characters and add one, you at that moment, using 400 bytes.

I did some tests and found that using indexOf() on Strings of more than about 160 characters, will fail, returning -1.
How did you generate these 160 characters?  Was this by concatenating strings until you got 160 characters to search?  If so, you might be running out of RAM which means the String isn't actually storing what you expected which is why indexOf is failing. 

Also can anyone suggest perhaps a better approach to the problem?  Thanks!
If you know the maximum number of characters you are going to deal with, then just use a character array.
4189  Using Arduino / Programming Questions / Re: Simple Scheduler on: November 27, 2011, 11:11:35 am
You might also want to look at Metro:
4190  Using Arduino / General Electronics / Re: Looking for a Arduino Mega 2560 development shield... on: November 27, 2011, 10:39:21 am
I am looking for a board that will permit a "Arduino Mega 2560" and any standard/mega shield to be plugged into it, with the relevant connections, switch/link selectable.

Does anyone know of such a board?
4191  Using Arduino / General Electronics / Re: Soldering for the beginner. on: November 27, 2011, 10:37:18 am
This has probably been covered a million times, but i'll ask anyways.
Indeed.  Although using your topic title as the search only finds around 400,000 pages on Google.

Hakko FX-888  Good Price... Excellent Tool.
Agreed.  I moved to the FX-888 recently.  The color scheme is silly but the iron works very well for the price.
4192  Using Arduino / General Electronics / Re: used digital multimeter on: November 27, 2011, 12:26:30 am
My old analog multimeter broke this morning so does anyone know of a website that sells used digital multimeters.
4193  Using Arduino / Project Guidance / Re: Detect VGA signal on: November 26, 2011, 05:51:00 pm
I have no idea how to implement ic2. do you have a quick down and dirty schematic / code example? also this wouldn't interfere with the signal transmission?

I'd worry more about interfering with the controlled impedance of the VGA's signal lines than the relatively slow I2C bus. You don't have to actively participate, just watch for the data or clock signal to toggle.  That will tell you the monitor is trying to talk to the projector.
4194  Using Arduino / Project Guidance / Re: Streaming video with my project on: November 25, 2011, 11:06:20 pm
Use Ustream?
4195  Using Arduino / Project Guidance / Re: Detect VGA signal on: November 25, 2011, 11:05:38 pm
Don't bother with the VGA signals, which are 75ohm paths.   Pins 12 and 15 are i2c pins.  You could just watch for activity on those lines.
4196  General Category / General Discussion / Re: Bootloader and FLASH / PROGMEM on: November 25, 2011, 12:24:35 pm
Thanks.  Missed it by searching for "bootloader" instead of "boot loader". (I didn't look at the TOC either, which would have shortened the search.)
4197  Using Arduino / Project Guidance / Re: Hardware for the beginner. on: November 25, 2011, 10:24:43 am
(As a side note, can the Arduino be coded with VHDL? I've barely studied the stuff, but it'll be on my final exam and it'd be great to mess with it at home on my own hardware)
No, VHDL is a hardware description language.  The Arduino is a microcontroller which is a set hardware implementation. 

In theory, you could use VHDL to describe the ATmega328s hardware, but you would still need to write software to do anything with it.  (this is how ARM processors get embedded into ASICs and FPGAs).
4198  General Category / General Discussion / Bootloader and FLASH / PROGMEM on: November 25, 2011, 09:58:24 am
Often the answer to huge variable constants is moving them to PROGMEM.  Sometimes people then ask if they can modify the data at runtime.  Ignoring for just a moment if this should be done, I have wondered what is the bootloader doing (or enabling) at allows it to write to PROGMEM that other running programs can't?
4199  Using Arduino / Programming Questions / Re: Writing to Flash Memory on: November 24, 2011, 11:30:50 pm
No, the running program cannot write to PROGMEM.

You might want to look into an external RAM or EEPROM chip.
4200  Community / Bar Sport / Re: Pin layout preferences on breakout boards on: November 24, 2011, 11:28:18 pm

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