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1  Using Arduino / General Electronics / Re: External power supply and Serial communication? on: July 27, 2014, 03:11:31 pm
I read the following online: If you plug in both USB power (say from a pc) and external power via the 2.1mm jack, the Arduino chooses power source automatically.

If the external 2.1mm DC is providing greater than 6.6V, the Arduino will take power from it instead of the USB.

Firstly, is this accurate?

Yes.

But you'll need more than 6.6V to get 5V out of the Arduino regulator.


Secondly, my real question: If I am powering my Arduino via external DC, can I still communicate with my Raspberry Pi using serial via the USB?

Yes.


2  Using Arduino / General Electronics / Re: Arduino Timer on: July 27, 2014, 01:28:36 pm
For reference, here is the code I used.
Code:
int speaker = 12;
void setup() {
  pinMode(speaker, OUTPUT);
}
void loop() {
  digitalWrite(speaker, HIGH);
  delay(2.272);
  digitalWrite(speaker, LOW);
  delay(2.272);
}
Code:
int speaker = 12;
void setup() {
  pinMode(speaker, OUTPUT);
}
void loop() {
  digitalWrite(speaker, HIGH);
  delay(1.136);
  digitalWrite(speaker, LOW);
  delay(1.136);
}

delay() doesn't accept floating point values...

3  Using Arduino / General Electronics / Re: Ground loops / High-Low frequencies on: July 27, 2014, 01:25:26 pm
There's lots of places I'd rework.

eg. On the capacitor below, go from Vcc to the capacitor and then on to the chip (light blue line). Don't make that weird 'h' shape in the track.

Some of the decoupling capacitors are much too far from their chips. eg. C22, C18...


4  Using Arduino / LEDs and Multiplexing / Re: seven segment display help on: July 27, 2014, 10:19:44 am
i can upload a schematic but i didnt think i needed cause i stated all pins go directly into the arduino ..

"schematic ... or your sketch"
5  Using Arduino / General Electronics / Re: Connecting Lm2904P on: July 27, 2014, 08:58:06 am
Hello!
I Have problem with lm2904p op amp.
I connected it using this schema:
As i know, output should be -3.3V in this case, but I have 0.81V...
What I am doing wrong?
(2, 3, 8, GND - lm2904 pins)

Simple:

a) You have it configured as an inverting amplifier so it went low when you expected it to go high
b) It isn't a "rail to rail" opamp so 0.8V is as low as it can go.
6  Using Arduino / Microcontrollers / Re: Intel Galileo has integrated linux OS on: July 27, 2014, 08:30:06 am
Quote
I guess they're relying on the "Intel" name to sell it to American corporations/educational institutions.
No, it is not a product in the normal Intel sense of the word. It came about because the new CEO of Intel was at a presentation from someone prototyping something with an Arduino. He offered this person special prices on the processor if he would switch to an Intel one, he refused. Then the offer was for millions off prices, then at cost price, and then for free. The person wanted to stick with the Arduino because of the "support community" around it. The CEO wanted "in to this" hence the Galileo which he described as "just the first in a series of like offerings".

Sounds plausible a Pointy Haired Boss trying to pound a blunt $60 peg into a $3 hole..

PS: I see they're already announcing "Galileo 2"

Quote
As a hobbyist it doesn't seem to offer much compared to (eg.) a Raspberry Pi at half the price.
I got mine for free at the Maker Fair, they had 400 they were handing out. I think I payed too much for it.  smiley

I was about to say "send it to me", but...

PS: There's people on eBay selling them for $125.
7  Using Arduino / Microcontrollers / Re: Intel Galileo has integrated linux OS on: July 27, 2014, 08:17:13 am
The Galileo does have the air of a very bodged rush job, even though done by a team with lots of resources.

Yep. There's no way Intel couldn't have made  a proper, memory mapped I/O chip for this.

It seems like they're only using the "Arduino compatible" thing for marketing purposes. It's the worst "Arduino" I can imagine.

I read somewhere that Microsoft will be doing Galileos with Windows running on them, their attempt to get into IoT.

Microsoft makes a lot of announcements.

As for Linux sources and documentation, good luck with that!

Amen.


yocto

From what I've seen Galileo uses some Linux distribution with a daemon (or whatever) to execute Arduino sketches whenever the IDE sends one.

I don't know what AndreyS is imagining he's going to find.
8  Using Arduino / Microcontrollers / Re: Serial baud rate on: July 27, 2014, 08:02:41 am
Aditionally i was also wondering what are the clock requirements to do so.  Lets immagine I use the built in oscillator on the mega328, running at 8Mhz:

.. in which case it's unlikely to work. Serial data needs very accurate timing.

Why do you need serial? There's lots of better, faster, more reliable ways to transmit data.

9  Using Arduino / General Electronics / Re: Ground loops / High-Low frequencies on: July 27, 2014, 07:50:27 am
There might be a problem, there might not.

It all depends on what you connect to your 74hc595 shift registers (which you're keeping a secret...)

10  Using Arduino / General Electronics / Re: Where to find pluggable 2.54mm terminal blocks? on: July 27, 2014, 06:55:27 am
Any more tips? Perhaps it doesn't exist?

I don't know what you're really after.
11  Using Arduino / General Electronics / Re: Are mobilephone LCDs useful for Arduino ? on: July 27, 2014, 06:48:54 am
Some are, some aren't. The older/simpler it is, the more chance you have of it working.

If you have a particular one in mind, ask in the "displays" section.
12  Using Arduino / Microcontrollers / Re: Intel Galileo has integrated linux OS on: July 27, 2014, 04:57:03 am
Quote
And then decide to buy Galileo or not.
Decide not.
The I/O on the Galileo is stupidly slow on all but two pins, so it rather limits what you can do with it.

It also takes 45 seconds to start running a sketch you previously uploaded from power up.

Yep. Makes me wonder what use it is. What are the people at Intel thinking?

I guess they're relying on the "Intel" name to sell it to American corporations/educational institutions.

As a hobbyist it doesn't seem to offer much compared to (eg.) a Raspberry Pi at half the price.
13  Using Arduino / Microcontrollers / Re: Intel Galileo has integrated linux OS on: July 27, 2014, 04:52:23 am
There is no documentation.

That wasn't what you asked for. You asked for "sources".

I've just gone through that 7z file. I saw lots of .patch files in "quark_linux_v3.8.7+v1.0.0.tar.gz", I have no clue what to do with them. No documentation. Maybe you know, dont you?
lots of code stuff here "Quark_EDKII_v1.0.0.tar.gz" but none linux related stuff.

There's more than one 7z file on that page I linked to...


14  Using Arduino / Microcontrollers / Re: Intel Galileo has integrated linux OS on: July 26, 2014, 01:59:42 pm
Anyone knows where I can download source for that embedded kernel with bootloader?

It's here: http://bit.ly/1lGTeHQ

lol, nice try bro,
If it was such simple I wouldn't ask for help

Huh?

The third result is "IntelĀ® Galileo software package" and it leads here: https://downloadcenter.intel.com/Detail_Desc.aspx?DwnldID=23171

Took me all of 15 seconds to find it.

15  Using Arduino / Microcontrollers / Re: Intel Galileo has integrated linux OS on: July 26, 2014, 10:09:04 am
Anyone knows where I can download source for that embedded kernel with bootloader?

It's here: http://bit.ly/1lGTeHQ
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