Arduino choices

seem to be nearly the same.

and place" robotics arm. School has a 3D printer and a laser cutter. We also have lots of motors and servos from VEX robotics kits. We could use the VEX controllers but I would like the students to learn an "open source" platform. Process will included sketching, designing parts using Auto Cad Inventor, printing the base, arms, knuckles, motor supports, gears, etc. with the 3D printers, winding a coil to create an electro-magnet as the pick up. Goal will be to autonomously and with joy sticks pick and place small metal discs.

purchase. Also what tutorials (books) would you recommend.

You should be able to get all the info you need from the Arduino Web site. It might be the most interesting for the students to build their own "Arduino" by mounting an Atmel Mega 328 chip and xtal on some vero board or similar (Look for "bare bones Arduino"). If you will need a lot of inputs and outputs perhaps the Atmel Mega 1280 would be a better choice but it comes as a surface mount chip so it's more practical to buy those as a completed board. I find the "Arduino Cookbook" by Argolis to cover all one might need to get started and more !!

Cheers ........ Rheilly P

Short answer: Arduino Uno

You only really need an Arduino Mega if you're going to write big programs. For everything else the Uno is better - more support, more shields, more code...

The extra I/O pins on the Mega aren't as big an advantage as they might appear, it's trivial to add more I/O to an Uno via shift registers, etc.

The mega is also very difficult to repair if you blow the chip by connecting up something you shouldn't. With an Uno it takes a few seconds to drop in a $3 replacement.

The best place for Arduino info is the Arduino web site.

For everything else the Uno is better - more support, more shields, more code...

appear, it's trivial to add more I/O to an Uno via shift registers, etc.

up something you shouldn't. With an Uno it takes a few seconds to drop in a $3 replacement.

One thing to remember is that Arduino gets harder to use the bigger the program is, because there's no in-circuit debugging: you have to use burn-and-crash.

The library is a big win for small stuff, and for getting something sort-of working quickly. For anything complicated, though, it's less work overall to code in C and use Eclipse.

If anybody has an Arduino-ish system with nice libraries and ICD, I'd be interested to know about it.

Cheers

Phil Hobbs

Yes there is...all the recent Atmel chips have "debugWIRE" debugging

The Arduino IDE doesn't do it, but it's possible.

Or just do what everybody else does and dump data to the PC via the serial port (or via Bluetooth, which is less intrusive)

Add a small two-wire screen to it:

Add a VGA monitor:

Or whatever... :-)

That's the point I was making. The Arduino hardware doesn't do it either.

Sure, I've done some of that--my son was interning with me this summer, learning gizmo-building and firmware. Burn-and-crash plus printf to serial is nowhere near as fast or useful as JTAG (or even DebugWire) plus Eclipse.

The library's nice, but it's not what you want for any serious sort of development.

Cheers

Phil Hobbs

s all seem to be nearly the same.

"pick and place" robotics arm. School has a 3D printer and a laser cutter. We also have lots of motors and servos from VEX robotics kits. We could use the VEX controllers but I would like the students to learn an "open sou rce" platform. Process will included sketching, designing parts using Auto Cad Inventor, printing the base, arms, knuckles, motor supports, gears, et c. with the 3D printers, winding a coil to create an electro-magnet as the pick up. Goal will be to autonomously and with joy sticks pick and place s mall metal discs.

o to purchase. Also what tutorials (books) would you recommend.

Thanks everybody, will go with the UNO. Already ordered it. Great group!! !!

It's all done via the reset pin so it's difficult for any hardware to NOT support it...you'd have to snip the pin off the chip.

I know how it's done--I've designed several ATmega gizmos in the last couple of years, one of which used a bidirectional level shifter on the reset pin. There's even an ISP header on the Arduino Uno board.

Since the Arduino development system doesn't support ISP, though, you have to go through all the pain of porting the library over to an Eclipse project, and once you've done that, what's the point of the Arduino-specific stuff anyway? You might as well save the code space used by the bootloader.

Having a standard interface pinout is nice and all, but the lack of source-level debugging really makes it more of a toy.

Cheers

Phil Hobbs

Yes it does. Arduino at its core is an ATMega328. Anything that chip supports, you can make Arduino do.

Arduino does ISP programming since v1.0. I use it all the time to program bare AVR chips on breadboards.

It has an ISP header, yes. Which works fine with Eclipse, yes. Which requires you to port the entire Arduino library to an Eclipse project, yuck.

Arduino is a toy.

Cheers

Phil Hobbs

If you polish it and apply a metal coating, you can use it as a make-up mirror too.

I've done several ATMega-based gizmos in the last couple of years, as I said already in this thread, so I'm familiar with both approaches.

From a hardware/software hacker POV, Arduino is a nice library and a set of standard interface pinouts, plus a stone-age development system. A serial port and blinkenlights? In 2012? You've got to be kidding me. They give away far more powerful tools than that for free, and what's more, I can use them on any processor family I like, rather than being limited to ATmegas.

I'm all for open-source hardware in its place, but for instrument development work, the lack of source-level hardware debug makes Arduino completely unsuitable. (Most of my stuff is sufficiently specialized that it wouldn't be of much interest to a very wide audience, so OSH doesn't come up much for me.)

My son interned with me this summer, learning how to build gizmos and write firmware. He started with Arduino, and then a barefoot ATmega board he built himself, switching to AVR Studio with a sigh of relief, although he did miss the nice Arduino library.

He wound up using the Eclipse-based LPCxpresso system for ARM Cortex M3s, which cost $30 all-up, and is a 120-MHz 32-bit processor with hardware divides and deterministic 12-cycle interrupts. It implements a full JTAG debug probe as well, so you can use the same h/w to develop stand-alone products.

It was a lot for a beginner to handle, but he got there eventually, and was able to prototype a reasonable chunk of the self-calibration code for an instrument. (It'll have to be rewritten some to reach a commercial standard, of course, but the final version will still owe a lot to his work.)

So IMO Arduino is great for sufficiently small projects, where having the community support, shield boards, and the nice library outweigh the

Cheers

Phil Hobbs

I bought these boards, for a couple Atmel based projects:

Yes, the point I was making, however, was that Arduino hardware does indeed support debugWIRE, contrary to your claim. None of the other points you made after that change that fact, even if they are otherwise valid and useful points.

You won't get any argument about the Arduino IDE being rubbish for debugging.

It's unlikely to change though. Writing a source-level debugger is HARD and I don't think there's anybody out there with enough motivation/resources to do it.

The Arduino people seem to be concentrating more on libraries for common hardware which are easy for inexperienced people to use.

Which seems unfortunate to me. Wiring seems useful for beginners, but it doesn't seem like it was really designed with portability in mind. It also doesn't build up abstractions, but simply creates a high level abstraction. I could easily see several mid-level abstractions that could have been created, so that more advanced programmers could create different high-level abstractions easily.

Then again, I haven't actually done what they've done, so who am I to judge ;-) I do appreciate Arduino, for without them, I probably wouldn't have embarked on my journey into Digital Electronics exploration the way that I have.

Wow, $5. Pretty tough to make a living at that rate!

Cheers

Phil Hobbs

But they don't need to write one, any more than they needed to write their own compiler from scratch (which is a bigger project than a debugger). What I don't understand is the lack of gdb/Eclipse support, or even a project for AVR Studio. The Dragon board is okay for light duty use, for instance, and costs $50.

It's a pity, because the Arduino library has a lot of nice features, but not enough for me to want to take on the porting job.

Cheers

Phil Hobbs

The Arduino scripts are in C. They are compiled & uploaded to the board. What does the Eclipse use?