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4681  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...

4682  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
4683  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?

4684  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"...?

4685  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?

4686  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)?

4687  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

4688  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).
4689  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
4690  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).

4691  Forum 2005-2010 (read only) / Frequently-Asked Questions / Re: Power Supply With Battery Packs on: November 10, 2010, 01:58:08 pm
The only thing is that the power distribution might be a little complicated for my "robot", which is pretty much 2 modded servos and soon a ping sensor in the front, but I'll keep this in mind for later projects.

Nonsense. The power distribution system of a robot is one of the most important items! Don't neglect it!

You are likely going to need a separate power source for your servos and probably the PING sensor anyhow. Set up a larger battery as I noted: Go to a hobby shop, and they should have pigtails/splitters to allow you to split the output of a pack into two. Feed one of the outputs into the barrel jack of the Arduino. Hook the other output up to another 7805 regulator (plenty of examples on the internet as to how to do this properly - you could also look at the schematic for the Arduino) to supply power to the other servos and the PING. Alternatively, you could hook up another regulator - a 7806 - to supply 6 VDC to the servos, while the 7805 supplies the PING.

Finally - if you can find them - go for low-dropout regulators (the 78xx/79xx series are not low-dropout) if you can; there are near drop-in replacements available for the more popular 78xx series regulators, but you have to do some searching.

Good luck in your project, though - whatever method you use (if you wanted to simplify things - if the above is over your head - then use two battery packs - an R/C pack for the Arduino, and a separate 4.8-6.0 VDC 4-cell AA pack for the servos, and run the PING off the Arduino's regulator (that will likely be about all you can run off the Arduino's regulator - you don't really want to do this, but it can work).

4692  Forum 2005-2010 (read only) / Frequently-Asked Questions / Re: Power Supply With Battery Packs on: November 10, 2010, 12:31:31 pm
As long as you replace the battery with some kind of jumper.  Most battery holders expect a continuous circuit.  An alternative might be to use rechargeable batteries.  They tend to run around 1.2V per battery, so four of those would be very close to 5V.

Depending on what is meant by mattloto for the term "robotics", it might be best to simply use 7.2 or 9.6 VDC rechargeable packs that are used in the radio-control hobby. They are plentiful, fairly inexpensive, and lightweight. They will supply more than enough voltage for the regulator, as well as plenty of current to run the Arduino as well as extra peripherals (servos, drive motors, etc).

In order to use them in this capacity, you would want to create some form of "power distribution" system, where the battery can plug in using a standard mating plug for the pack, and has an output plug that will plug into the Arduino's barrel jack, as well as extra leads or plugs to power any other devices. Ideally this would all be implemented on a separate PCB, and there would be regulators implemented on-board to supply the voltages to the extra devices as needed, as well as perhaps a "raw" voltage source (clearly marked and positioned, of course).

4693  Forum 2005-2010 (read only) / Frequently-Asked Questions / Re: Looking for a complete labeled Lilypad diagram on: April 20, 2010, 04:10:34 pm
I -think- this is how things are, based on the image and the schematic:

Starting from 12 o'clock on the LilyPad image, the first pad is Pin 0-RX/D0. Moving counter-clockwise are:

Pin 1 - TX/D1
Pins 2,3,4 - D2, D3, D4
Pin 5 - GND or "-" (ground)
Pin 6 - VCC or "+" (power)
Pins 7,8,9,10,11,12,13,14,15 - D5 thru D13
Pins 16,17,18,19,20,21 - A0 thru A5 (analog pins)

J2, viewing the pins as oriented in the photo, is more tricky - I am basing this pinout on the fact that pin 6 appears to be connected to some SMT part, which I think is a decoupling cap on the schematic (to ground), so pin 1 on J2 would be on the left hand side of that photo:

Pin 1 - DTR
Pin 2 - RX1
Pin 3 - TX0
Pin 4 - VCC
Pin 5 - CTS (pulled LOW to ground)
Pin 6 - GND

Once again, this is all an "educated" guess based on what I can see in the diagram and the photo; take it for what it is worth, which isn't much (if I had one in hand, or a larger photo front and back of the board, it would be easier).

Hope this helps - double check everything I wrote above before using (I really don't trust my guess due to lack of information and not having ever used a LilyPad). Maybe someone else can verify this guess?

4694  Forum 2005-2010 (read only) / Frequently-Asked Questions / Re: Bot Steering Question on: November 06, 2010, 06:56:58 pm
You would steer the same way you would a treaded vehicle like a tank.  To turn left, you would go forward with the right 2 wheels and in reverse with the left 2 wheels.  It is less of a turn and more like a rotation.


In addition, if you want to do a gradual turn with a differentially steered robot chassis, you vary the speed of the treads by different amounts while they are going in the same direction. This can be done using the PWM speed selection mode of your controller for each motor.

What is really interesting about this platform though, is the fact that you have in actuality four independent "wheels" in a differential arrangement, but that are independently controlled; this is unlike a standard tank-tread differential steered vehicle, since such a vehicle only has two "wheels" to control (each tread). Perhaps by varying the speed and direction of the independent wheels, some other control/steering mode may be available? Sounds like something to experiment with!

Also - if you can actively brake the motors, that would be best, but those gearmotors might not backdrive well, so braking may be unnecessary.

4695  Forum 2005-2010 (read only) / Frequently-Asked Questions / Re: Arduino Without Board on: November 05, 2010, 04:30:31 pm
Ok - so you now know you can do a standalone Arduino - great! However, this statement of yours:

One of my mental barriers with the Arduino is the idea that any project will cost me at least $30 for the board.

While I can understand it, I have to inject a bit of perspective here:

When I started with the Ardunio, I did so because my OS platform I had switched to (64-bit Ubuntu) no longer supported the byte-code compiler for the Parallax Basic Stamp 2 (due to statically linked 32-bit libraries - ugh!); the compiler was binary only, and Parallax was no longer supporting it, nor did they have the source code or know where the original programmer ran off to. I was stuck.

Looking around, somehow I ran across the Arduino! Here was a system that even from one of the more expensive vendors (say, SparkFun) - was only going to cost $30.00 for the entire board!

The Parallax Basic Stamp 2 in the 0.600 DIP format cost about $50.00 at the time. I though the Arduino was a bargain. After I had done a bit of browsing the site, looking at the schematics, and reading about the standalone version (and price shopping the ATMega168) - I was really sold on it.

So - long story short - it could be worse - a lot worse. While in practice you could easily do a "standalone" PIC system, you would still have to purchase a compiler for it (C or BASIC), as the only open-source compiler for C on the PIC only supports a small subset of the PIC lineup - and those compilers aren't too cheap (I won't lie - they won't break the bank, either), plus they only run on Windows.

Good luck with building a standalone!

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