Actually there are loads of these things and a guaranteed unknown amount more if the Incompleteness Theorem is right. And that's a good thing since it means science will never be done if that's true.

Amen to that.

The right side people (in the scale), like Physicists, Chemists, Biologist, Astronomers, etc are all in accordance that science is an evolving thing, that there are more questions to be made than answers already found. Most of these people call what they do science rather than a profession. My wife, for example, has a PhD in cellular biology and has just started her post-doctorate in odontology. She calls herself a scientist, not a dentist.

To the left of the scale, the more applied people, can be divided into 2 categories: those that consider it a profession and those very few that consider it a science. The professionals usually think that their knowledge is an already evovled thing, that whatever there is to know has already been written. I know SEVERAL medics/doctors that are like that. They refuse to acknowledge that medicine is a science as well, and are more likely to think that everything they need to know, now and in 50 years, is already in the books. The same goes for several psychologists, sociologists, etc.

To a certain extent, we can also call religion a science (I am intentionally not using the word teology), because whatever faith we follow, how we deal with it has changed over the last hundred of years, at least in the western religions. We aren`t as tight ass about religion as out ancestors were 100-200 or 300 years ago. People in Massachussets don't hunt witches anymore. The Pope doesn't have that much influence in governments. Only recently some churches (as in "institutions") have acknowledged that our relation to whatever Superior Being we believe in has changed.

A dog makes a good sensor.

I was about to post the same thing.

If the cat is Schrödinger's cat, you may need a Geiger Counter. Fortunately, there is already a shield for that.

Electronics is Math.

Isn't mostly everything?

Some forum user ask why they do not step up to the next level (Eagle). You already wrote the answer:

because I haven't had the time to tackle Eagle yet

My 2 cents:
The next level isn't Eagle, but some easier to learn package, like DipTrace. I learned DipTrace fairly quick, and currently I feel absolutely no need to invest (more) time learning Eagle.

By more time, I mean that I have tried to learn Eagle, only to find it counter-intuitive to use. I know it is extremely powerful and capable of doing a few things I still don't know how to do in DipTrace, but, neverthless, for someone to has electronics just as a hobby, DipTrace is more than enough. Even for most students, DipTrace will suffice.

What I REALLY miss, however, is an updated version of something like Electronics Workbench, which I used a lot back in college (in the 90s). I never took the time to learn SPICE. Too bad that NI's Multisim is too expensive.

So to start out you have a fan header on a motherboard which through its own software will regulate the voltage coming out of the line and defaults at 12V.

Not necessarily. The 4-pin fans will not variate voltage. Instead it will have a PWM signal in the 4th pin, that is basically a really fast turn-on/turn-off signal. That will make the fan's speed vary.

117  leds give or take. connected a 9v with no resistors and they all lit up nice and bright. I don't know what I learned but I like it.

If your 9V source wasn't a battery (that has a very limited current capacity), but instead was a bench supply, a wall wart or any other source of AC-DC adapter, you'd have learned what it means to divide V/R when R=0: you get inifinite current (well, not infinite, but very high). All of your leds would give a very bright glow, right before exploding or simply dying. If your LEDs had held the high current (very unlikely), you might have had a blown fuse in the power supply.

So you learned that 9V batteries have an internal resistance that limits its maximum current.

Graynomad, thank you, mate! +1 karma for you!

I'll tell you why:
I have developed a patent-pending product that uses 10x MAX7219. The problem is that the MAX7219 is VERY expensive (even when bought in thousands). Until yesterday, I had no idea that there were direct replacements for it, until you posted about the AS1108. I went on to learn more about AMS and the AS11xx series and I found an IC that is a direct replacement for the MAX7219, the AS1100, and it costs less than half the price of the Maxim IC.

I had been looking high and low for that, and thanks to this thread and this post I found it. I've ordered a few samples from AMS and I'll report back when I get them and test them.

Thank you very much once more.

@petere10

I've bough stuff from DX for a long time and never had trouble with them. Actually most of the arduino-related stuff I have is from DX. They are that cheap. The only downside is that packages from them take forever to arrive, with a 30-35 days delivery time being quite normal.

Another suggestion I make to you is products based on the TM1638, specially this one. It has 8x 7segs + 8 bi-color leds + 8 buttons, everything controlled by a single TM1638, for which there are very good, working libraries for Arduino.

Recently I got an entirely new, inspiring, view of what reCAPTCHAs really are, after watching the TED Talk below:

Luis von Ahn: Massive-scale online collaboration
http://www.ted.com/talks/luis_von_ahn_massive_scale_online_collaboration.html

Until then, I used to find CAPTCHAs a real PITA, an annoyance. Now I find them inspiring, and the tecnology behind it to be awesome. I am so amazed with it that I felt like sharing that with you.

I won't spoil the surprise... please watch the video above and we'll talk after the break.

One thing is sure: I'll never fell annoyed by reCAPTCHAs again!

It seems like you have a 328-PU (normal power) and NOT a 328P-PU (low power);

They have different signatures, and that seems to be the root of your problems.

Open avrdude.conf, look for the 328P-PU signature and change it to match the 328-PU.

I don't have the Arduino IDE installed in the computer I am using right now, otherwise I could tell you exactly what line to change. With a 30 seconds search on these forums, you'll be able to do that, 'though.

I made the adafruit shield but I modified it so that I could plug the 6 pin ISP cable into any ISP connector and program the chip from my shield...

I've done the exact same thing! My shield has an ICSP header and a jumper, which determines if the MCU being flashed gets its RESET signal from the ICSP header or from the shield. I also used a clone of the Ada Arduino Protoboard as a basis for my build, and I added a couple bypass caps to the board as well, just to be safe.

I suggest the MAX7219 or MAX7221

Each MAX7219/7221 can drive up to 8 digits of 7-segment display. They are easy to work with (SPI, 3-wire) and daisy-chainable. They also come in 24-pin DIP packages AND there is an automotive version available (which I think might suit you better than the regular version).

There is plenty of examples out there that uses the MAX7219 with Arduinos, driving either led matrices or 7-sd's

[:]

Try this:

copy com5: file.txt

Note the ":" after the COM port specification

Minha dúvida é: realmente vale a pena utilizar este transistor a mais? Estou ganhando algo em termo de qualidade ou segurança?

Objetivamente: NÃO!

Não vale a pena. Use ou um ou outro. Usar os 2 é preciosismo demais, e aumenta não apenas a complexidade do circuito, mas o custo do projeto. É mais uma coisa para dar errado.

Acho que 99% dos circuitos que relé usando Arduino que conheço, usam apenas 1 das duas formas de acionamento (ou Opto ou transistor)

The on-board Serial-To-USB adapter in most Arduinos (includig the Mega and UNO) is connected to Serial0.

In the Mega2560, in order to see the output of the other serial ports, you need to connect other serial devices to it.

I am not sure if I have to keep maintaining this mod anymore  because I recently noticed that Arduino team finally added a Windows installer for the official version http://arduino.cc/en/Main/Software also soon official version will have scroll, and other goodness.

I haven't checked yet if they fixed all the small details like the icons and so, but it seems they finally took action on some of the complains over the Windows version, and that is certainly good but makes this version a bit pointless.

Well, buddy, I hope you DON'T stop improving your version. It is so much better than the official IDE in so many aspects....

For example, whoever develops the official IDE, is unable to fix the bluetooth compatibility problem, and everytime the official IDE has to enumerate serial ports, it hangs it the bluetooth is on. On my notebook, for example, I have to disable bluetooth, and therefore the Wi-fi card, just to start the ofcicial IDE. That is one bug that pisses me off.

I know you are working on a way to upload just the HEX files to the Arduino (I suggested that too!), so and that will be a very valuable addition to the enhanced IDE.

In other words, your IDE is years ahead of the official IDE. Please don't stop.

If it as matter of lack of Pepsi, please let us know!