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4666  Forum 2005-2010 (read only) / Frequently-Asked Questions / Re: Making a needle glow (1000°C) by Battery on: June 18, 2010, 12:44:55 pm
jazzar, you are playing around with things that have a high potential for harm (potentially death); be careful.

You may want to research the "high voltage" community for tips, tricks, and techniques. Probably the area most relevant to what you are trying to do would be "quarter shrinkers", "water exploding", and "coil guns" - all three of these in the "high voltage" community involve shorting large capacitor banks into coils or spark gaps. There would be details on how to "switch" such banks properly.

There are tons of web sites dealing with the subject of "high voltage", and plenty of discussion forums, too. You may be able to get more information and discussion on how to do what you want to do from them (then, when you are able to do things in that case, you can come back here to learn how to hook up the Arduino to it and control it).

Good luck with your glowing/exploding needle project (and please, be careful - wear goggles, and one hand in pocket at all times)...

4667  Forum 2005-2010 (read only) / Frequently-Asked Questions / Re: Stepper Motor Rating on: November 15, 2010, 07:51:40 pm
You can't drive anything more than 40mA directly using any digital/analog pins, excessive current draw will likely damage your chip.

Maybe he means the output from the regulator?

Even so, this is really not something that should be done; it is likely that the motor could draw enough current to cause the Arduino to reset or possibly damage the regulator. The motor should be powered separately with its own power supply (just remember to tie its ground together with the Arduino's ground).

4668  Forum 2005-2010 (read only) / Frequently-Asked Questions / Re: OOP (object oriented programming) on: November 16, 2010, 10:57:19 am
First off, OOP is more of a programming methodology than something that requires intrinsic language support (though don't get me wrong - having such support is usually needed for successfully implementing the OOP methodology in a particular language).

The Arduino system is based off of C/C++, and since C++ is OOP, then yes "Arduino supports OOP".

With that said, you won't see many people using C++ and OOP outside of libraries with the Arduino; I am not sure why that is, but I suspect it has mostly to do with the level of most user's experience with programming, the fact that functional programming can solve 99% of problems the Arduino is used for, and the "straightforwardness" of functional programming (making it easier for beginners).

You tend to see OOP used for libraries because it provides for an easier end-user experience, plus most (all?) of the tutorials on making a library revolve around doing it in C++/OPP fashion.

There is no reason why you couldn't do the same with the rest of the system (however, setup() and loop() would have to remain functions outside of a class - but you could conceivably do everything else inside custom classes instantiated and called from those two functions); at least, I don't think there is (but I have never tried myself)...

Maybe someone else here can give more insight...?

4669  Forum 2005-2010 (read only) / Frequently-Asked Questions / Re: Newcomer to Arduino. Point me in right direction? on: November 04, 2010, 06:02:02 pm
You might want to take a look at this project - while it may be larger than what you need, the principles are the same:
4670  Forum 2005-2010 (read only) / Frequently-Asked Questions / Re: Sparkfun Free Day on: July 18, 2010, 04:29:44 pm
Somehow I doubt there will be another one and I am also glad of that.

I agree - that was one maddening morning.

What I found really funny is that the whole reason for the "free day" was to act as a load test for their new server system; given the number of people who just plain couldn't order or even see the site on that day, I personally think it was a failure.
4671  Forum 2005-2010 (read only) / Frequently-Asked Questions / Re: New Icon? on: September 26, 2010, 11:54:58 pm
Well - I have to say that I like the new icon; it would probably look good on the taskbar, as the IDE icon, etc. I was worried it was going to stay that "teal" dot...

4672  Forum 2005-2010 (read only) / Frequently-Asked Questions / Re: New Icon? on: September 13, 2010, 04:18:07 pm
I just hope, whatever the new hardware or software does, that they change the icon - that has to be one of the most boring favicons I've seen (heck, my website favicon is more exciting, and I think its pretty bad, too). Hopefully its a placeholder for something better when they release.

Also - why wasn't there ever any 16 bit microcontrollers; "they" completely skipped a generation.  ;D
4673  Forum 2005-2010 (read only) / Frequently-Asked Questions / Re: New Icon? on: September 11, 2010, 04:08:36 pm
And on a totally random side note, guess what song I have stuck in my head!:
hint:  Ra-urrh,rah,rah-urrh ,Rah,ja-urh-ur-ra!!!!!!

Lady Gaga, Bad Romance?

4674  Forum 2005-2010 (read only) / Frequently-Asked Questions / Re: New Icon? on: September 09, 2010, 06:00:36 pm
Ok, it isn't green - seems closest to "teal"...?

4675  Forum 2005-2010 (read only) / Frequently-Asked Questions / Re: New Icon? on: September 09, 2010, 12:06:37 pm
I'm gonna venture to guess that it is related...

Hmm - I guess you're right.

Which brings up another question - how many people on these forums go to the front page of the site? I know I rarely do; one would think the "A-Team" would at least announce site changes (and I don't know - things like the release of a new version of the Arduino IDE, as so recently happened) in the News section of this forum.

But they don't. What's the point of even having a News section, then?

4676  Forum 2005-2010 (read only) / Frequently-Asked Questions / New Icon? on: September 09, 2010, 11:27:51 am
Last night I noticed that the site's icon changed - when and why was this decided (and why a green dot)?

4677  Forum 2005-2010 (read only) / Frequently-Asked Questions / Re: Arduino pin cheat sheet? on: November 12, 2010, 11:52:37 am
There's also a -free- app for the Android platform called "Electronica" that recently had an update to include a picture of the Arduino board with pinout labels. It identifies which pins are what (but not the port groupings, unfortunately).

The author is fairly responsive, though - so if you like the app (it has a bunch of other useful features - resistor codes, capacitor values, pinouts for other things, LED calculator, etc), you can tell him and he'll look into updates (its from

4678  Forum 2005-2010 (read only) / Frequently-Asked Questions / Re: Creating a Component Video, IR controlled switch? on: February 09, 2010, 01:07:30 am

Yes, you could use relays - you would only need a single IR remote receiver module (not one per set of relays) to control it, plus the code sequences, etc.

If you used relays, it would probably be best to use 4PDT relays (one line per connector, plus common signal ground), and keep all connections to the I/O jacks as close and short as possible to the relays (plus incorporate ground planes, etc on the board if using a PCB) to keep noise and crosstalk in the signals to a minimum (this is a good idea regardless of whether you are using ICs or relays to switch).

If you couldn't find 4PDT relays, two DPDT relays could work, too (plus you can find smaller 5V DIP versions if space is a concern).
4679  Forum 2005-2010 (read only) / Frequently-Asked Questions / Re: Creating a Component Video, IR controlled switch? on: January 31, 2010, 04:44:11 pm
BTW, Component video is the one with the Re, Green ,and Blue connectors. Composite is the one that uses the Yellow, Red, and White connectors.

Well, actually Mike, composite video is only the yellow RCA connector; the red and white connectors are right and left audio, respectively (just got done hooking up a new LCD TV - on a break right now!).

topho, you're going to need however many of those component switch ICs as you have inputs (those chips are pretty nifty!), of course, but they're probably not too expensive, then your Arduino would select the enable lines via the digital outputs, of course.

Now, something else: are you just trying to make a cheap remote controlled switch, or is the Arduino there to allow (for instance) a computer connected via the USB serial port to switch the inputs, too (say, for a computer-controlled CCTV camera switcher)? Because if your goal is -only- a cheap switch (well, cheaper than you may be able to buy), then using an Arduino for the remote-control conversion is a kinda pricey way to go about doing it.

If your goal, though, is to have the Arduino do the switching based on external inputs (say a sensor, or commands from USB), then this is a perfect way to do it (and if you can use EagleCAD, it would be an awesome Arduino-based product that people would probably buy, especially if it were in kit form).

Good luck, and don't forget to let us see the results!  smiley
4680  Forum 2005-2010 (read only) / Frequently-Asked Questions / Re: program's weight in card ? on: November 10, 2010, 12:45:36 pm
However the problem is that while you can add external memory you can't make the processor "see it" as part of it's system so it is of limited use.

Natively, it couldn't.

However, if you implemented a small RTOS on top of the ATMega, with its own custom "scripting" engine, you could in theory set things up to utilize extra memory (anything from serial EEPROMS to SD cards, etc) in a transparent manner (similar to how old 8-bit operating systems, like OS-9 for the TRS-80 Color Computer, used the floppy drive to emulate a form of virtual memory).

Of course, in the end you would have all the overhead of the operating system, and less real memory to play with (and 2K on the 328 still might not be enough to implement the RTOS plus virtual memory, etc), and your scripting engine wouldn't run its code as fast as native code, of course.

But you would gain the ability to have larger programs (with bits swapped in and out as needed - modules, in a way), as well as multi-tasking (of a sort), and the possibility of an on-board command line/interpreter/programming environment.

I know there have been a few small RTOS systems created for the ATMega168/328 (some targeted for the Arduino); I've never looked at just how sophisticated they were, so while I know that some of the few I've seen support some of the above, I don't know if they support all of it.

Finally - while I can appreciate the "hack" value of implementing such a system on a microcontroller like the ATMega, in some way I also feel its a solution searching for problem: When you need that kind of sophistication, cramming the functionality into a small microcontroller may not be the best solution, considering the abundant availability of other solutions more suitable to the task (most of them are fairly inexpensive, and some at the top end of the range can even run full-size operating systems if that's a need).

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