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4186  Using Arduino / Programming Questions / Re: Read time differences in nanoseconds on: December 06, 2011, 10:55:30 pm
millis() and micros() are time stamps of how many milliseconds and microseconds the processor has been running.

pseudo-code:
Code:
  long firstStamp = millis();
  // whatever happens
  long secondStamp = millis();
  long elapsedTime = SecondStamp - firstStamp;
4187  Community / Bar Sport / Re: Something to do with those extra PCBs on: December 06, 2011, 10:33:55 pm
Great idea!

I have a batch that came back with a power and ground plane shorted together.  I re-worked one but was about to just throw out the rest.
4188  Community / Bar Sport / Re: Arduino DUE, some thoughts on: December 06, 2011, 10:20:12 pm
Tell that to the thousands of PC's with single core CPU's. I know they aren't running literally at the same time. But it's going to do a helluvalot better job of faking it than an 8bit CPU could.
PCs are also running an operating system which supervises the multitasking.

ADC - There are a total of 16 analogue inputs, same as the Mega but better in that there are two 8-ch ADCs, one is high speed (1Msps) and high(er) res (12-bit), and the other is more like the Mega (10-bit, 384ksps)
Any insight if both A/Ds can be used at the same time?  Or at all 16 inputs MUXed into a single A/D?
4189  Using Arduino / General Electronics / Re: Simulation software on: December 06, 2011, 09:57:13 pm
I use this one: http://www.falstad.com/circuit/

And it's iOS cousin, iCircuit.
4190  Using Arduino / General Electronics / Re: Staying organized? on: December 06, 2011, 07:53:47 pm
Wow.  I never tried the phrase "SMT component box" on eBay.  I tried variants on box, case, snap, etc.  It wasn't until I used "SMT" that I found them in bulk.  Thanks.

Quote
I melt my dividers in place. 
Good idea...
4191  Using Arduino / Installation & Troubleshooting / Re: Arduino power distribution? on: December 06, 2011, 07:45:27 pm
Quote
You don't have a jumper to select DC or USB power ?
The Decillia was the last Arduino to have a header.

Since then, an auto selector circuit determines USB or Vin/Barrel.

Quote
What are the details on the power distribution for the Uno? If USB and the DC-in power is connected, which is preferred?
If both are connected, and DC-in is about 7.5V or higher then the DC-barrel/Vin will be selected.  As for why having both connected allows for operation?  Not clear why that would be the case.  Maybe as current draw goes up, voltage on the rails drops and the MOSFET keeps switching back and forth?

What else do you have connected?  An Arduino and just the Ethernet shield should operate fine over USB.
4192  Using Arduino / Programming Questions / Re: OpenCV? on: December 06, 2011, 07:37:58 pm
Because i want to create an application that involves a camera, and motion tracking, any points of wisdom on how to intergrate Open CV?

Don't use an Arduino.  It is a microcontroller, not a microprocessor.
4193  Using Arduino / General Electronics / Re: Staying organized? on: December 06, 2011, 07:27:22 pm
The removable divider boxes bother me because the dividers tend to move up and let parts mix together.

I like these because they are individual boxes.  There are different sizes available.  Plus they are esd safe.  I wish I could find where she buys them.

https://www.adafruit.com/products/427
4194  Using Arduino / Programming Questions / Re: 1.7" OLED Display Shield and Arduino 1.0 on: December 06, 2011, 06:19:36 pm
If you are just getting started, roll back to 0022 or 0023.  1.0 has only been, officially, out for a couple of days.

A few weeks on the older branch probably makes more sense.  Just about all tutorials and code examples available right now will work just fine.  The experience you gain will transition nicely to 1.0 (or maybe by that time, 1.1).
4195  Using Arduino / Installation & Troubleshooting / Re: Serial communication Arduino on: December 06, 2011, 03:52:20 pm
The DC voltage for a high (1) is 5V. 

However, if the pin is transmitting it means the signal is toggling 0 to 5 to 0.  On average, this means you would measure a DC voltage of 2.5V.  It is not surprising you see 2.7V.

You really an oscilloscope to see the full voltage.
4196  Using Arduino / Installation & Troubleshooting / Re: Is the driver for windows unable to set certain baud rates on: December 06, 2011, 03:50:19 pm
The problem is probably not with the PC side but with the Arduino itself.  The baud rate is a multiple of the 8u2's clock.  So some baud rates might not divide out in a way that works well.
4197  Using Arduino / Microcontrollers / Re: ATMega 168 Vs 328 on: December 06, 2011, 02:30:22 pm
What are the major differences between these 2 beside the flash side  and ram i?
That's the only difference.

RAM:  1k vs 2k
FLASH:  16k vs 32k
EEPROM:  512bytes vs 1k
4198  General Category / General Discussion / Re: Arduino Uno and Motorola Xoom on: December 06, 2011, 02:22:53 pm
All I would like to do
Keep in mind that there are many (many) layers of software, drivers, firmware, and even hardware at play to make an Arduino work with a PC.  Many of those layers have over 10 years of legacy attached to them.  Tablet operating systems don't necessarily carry of that legacy with them.

connect  my Uno to my Motorola Xoom (via usb , as I have the attachment with the USB port on the end, like the camera attachement).
If your Xoom doesn't have drivers for a USB to Serial device (which is what the Arduino appears as to a host) then connecting it won't do any good.  It is possible it does, but I don't know enough about the Xoom's implementation of Android to know that answer.  Besides, unless you are running an application that takes to the serial port, what would you expect your Xoom to do when an Arduino is connected?

Once connected I just need my "Android App" to turn on and turn off a relay connected to my UNO. I thought it would be possible to do all of this WITHOUT a USB host shield!...
I'm not sure I understand where a host shield comes into play?  A host shield would be used so that you could connect USB devices to an Arduino.   In this case your Arduino is the device and the Xoom is the host.
4199  Using Arduino / Programming Questions / Re: 1.7" OLED Display Shield and Arduino 1.0 on: December 06, 2011, 01:30:58 pm
Quote
The code works in Arduino 0.22 but not 1.0.
Can anyone tell me why please?
Yes, 1.0 has major changes compared to 0022. 

You can try adding "#include <Arduino.h>" to the top of your sketch.  However, since the library makes use of the Serial library you probably need to contain the library's author to see if they are working on a version compatible with 1.0.
4200  Using Arduino / Programming Questions / Re: LED display for web data on: December 06, 2011, 01:09:25 pm
and functions aren't used.  I will look into storing variables as program memory. I'm currently using a Duemilanove 382 with an ethernet shield, but would like to use the integrated AruinoEthernet.

You mean a Duemilanove which uses a ATmega328.  That only has 2K of RAM.  Every global variable declared will consume memory as well as each String, such as:
Code:
    client.println("GET #########");
will also consume RAM.

This array:  "char defaultText[numLines][40]"  takes up 120 bytes.  That's 12% of your total available SRAM on a single array, not to mention all of the other stuff you are doing.
Then you have this string:  "String charLookup  = " 0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ!@#$%^&*(),-.?></\\|[]_=+:'\"{}";"
That's another 100 bytes, so now 20% of the RAM is gone and your program hasn't even started doing anything yet!

You need to move all of your Strings to PROGMEM (link already provided.)

Every LCD or Serial print needs to come out of PROGMEM, other wise, the string will use up RAM.
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