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What Micro-Controller Would You Use to Teach With?
Rukie asks: "I'm looking into starting some sort of robotics class for my high school, which severely lacks any sort of technological classes. I am now wondering what micro-controllers are best for an educational environment. I definitely want something more advanced than the Legos, but something that won't fly over people's heads. Are there cheap, scaleable micro-controllers for learning in a classroom or at home? I'm curious how my fellow readers have hacked up toys to make their own robotics at minimal cost."
Check out http://www.parallax.com/ and their Basic Stamp series. They have a wide range or processors and great educational programs based on them. The also have robots and robotics based programs based upon the Basic Stamp.
I like the Brainstem from Acroname. I haven't done any big projects with one, but I've played with a couple and they definitely hit the spot in terms of easeability, powerfulity and economicalness. I've used the SV203 from Pontech in the past and it's a solid & simple board. Great if you're keeping the board tethered to a computer and not doing any actual processing on board. Brainstem gives you a little/lot more high level power.
The 6808 micro-controller (long version of the name is M9S08GB60) would be excellent for teaching a class on robotics. As its been around since the dawn of time, there's a lot of support readily available for it. Complete, detailed reference manuals are freely available, Freescale will even ship printed copies to you for free. Compilers are available that allow you to program in your choice of assembly, C, or C+. The "M68DEMO908GB60" demo board is available from many online retailers for around $50 which makes it easier to use the microcontroller for prototyping as well as experimentation and class labs.
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What lends the 6808 microcontroller is its Pulse-Width-Modulation components (it has 2 modules, one with 5 channels and the other with 3 channels and all channels can be set up for either incoming our outgoing). In addition to all that it runs up to 40MHz without cooling and includes 4K of RAM and 60K of ROM all on-die, so no extra chips for those. It has more power than you could ever hope to use in a class-room.
A good example project is available here: http://home.comcast.net/~starwreck/FinalReport.pd
... and in the DRM, bind them.
As much as I love the open source Arduino board for my own personal use, and even though the basic STAMP is raher expensive (even with the education discount), Parallax has an extremely thourough set of documentation that is perfect for an educational environment. They have a fee book available for download called "What is a Microcontroller" that should fit all your needs. It contains a series of predesigned lessons that assume no technical experience for your students. All your lesson plans are done for you.
I don't know, I think he is going more for a "fun" angle. Lets face it, without even the basics of electronics, going to digital circuits is tricky at best.
That being said, I would recommend a Basic Stamp from http://www.parallax.com/. While their chips are not the fastest, cheapest, or fully featured they offer EXCLELENT learning tools, books as well as a wealth of free code. There are plenty of robot kits you can get and easy to plug in designs. You can quite possibly even get a bulk discount for a school.
To be honest, I would rather have a class where the first half of the semester is designing AND building your radio. (Preferably FM) I learned microcontrollers first before I learned anything about analog components and a radio is the best way to teach that.
I'd go with Atmel AVRs.
They are widely used, well documented and well supported.
There are a large range of chips with a consistent instruction set, so they can learn on a simple eight pin 1-Kbyte chip and then apply that knowledge the next day on a large 32-pin 16-Kbyte device.
They are extensively used in industry so students can feel like they are learning something practical.
Anybody even remotely interested in serious robotics at a high school level will have already completed Algebra in 8th grade. Everyone else is to busy talking about/having sex to care.
Extracurricular groups sound great, except no one ever has time for them. I cannot spend my time doing an extracurricular activity when I have 4 hours of homework each night. Again students interested in robotics will have significant homework each day. I agree with that, except that AP Physics C covers a great deal of the basics of circuits and EM.
AP Physics C should be offered at ALL high schools, if it is not then he shouldn't be trying to add another elective.
Teaching how a computer works is a GREAT idea. Frankly no one really gets it.
Internet resources for figuring out how computers work is great and all, but a real classroom experience cannot be beaten here.
As a side note:
Most people have absolutely no idea how a computer works. I don't care. No they don't need to know. No I'm not going to tell them they are stupid. I don't know how to do a French manicure, does that mean I'm stupid? didn't think so
I'd recommend Atmel AVRs without a moment's hesitation.
The PIC and 8051 grew from architectures that were considered spartan and stripped to the bone a generation ago, and got a foothold only because (compared the "real" CPUs) they were somewhat affordable. They've matured, of course... but people who start on PICs almost inevitably get saddled with all the legacy baggage. In contrast, people whose first exposure is to Atmel or Motorola take one look at the PIC's legacy stuff, say "eeeewwww!", skip the first 20 chapters of the book, and go right to the good (modern) stuff.
The Motorola/Freescale MCUs are powerful, but they're NOT for newbies.
The nice thing about AVRs is that they're fairly robust and hard to permanently kill. I've abused AVRs pretty badly, and I've NEVER had one permanently die on me. There were a few I'd thought were dead, but ultimately they were all resurrected via high-voltage programming or by supplying an external clock signal to them. I've grossly exceeded the i/o pins' current-draw capabilities, connected power backwards, created pin-to-pin shorts, and still lived to tell about it. From what I've read, other platforms aren't quite as forgiving and wantonly abusable as AVRs. I know people who've driven 5v-relays straight from AVR i/o pins.
AVRs also have a great resource -- avrfreaks.net
AVR development tools are fairly cheap. An ISP-only programmer costs around $30-35. The Dragon costs $50, but adds support for high-voltage programming (handy for fixing messed up fusebits and reviving chips that otherwise appear to be dead) and Debugwire (think of it as single-wire JTAG for debugging). Unless you actually care about compatibility with Atmel's old chips, I'd recommend a Dragon over the STK500, if only for the Dragon's Debugwire capabilities.
AVR Studio is a free IDE (Windows only, though... but I think there's a Linux alternative) that natively supports assembly, but also integrates seamlessly with WinAVR for C/C99/C++ (of the 3, C99 is the one I find the most useful... it basically gives you the linguistic niceties of C++, like parametric polymorphism, without the huge libraries and resource requirements normally required for full-blown C++).
One major tip: if you want to use C (or eventually C99 or C++), buy John Pardue's book ("C Programming for Microcontrollers) and a Butterfly. He sells it directly from his website (smileymicros.com) for less than it costs from Amazon, and you can pick up the relevant hardware from him for less than you'd spend buying it all from Digikey. No, it's not the greatest book on C programming ever written... but it's the single best book you can get for learning C as it applies to AVR microcontrollers. Remember, 99% of C is learning how to use its libraries. Let's just say that time spent learning to use stdio in a generic C programming book isn't going to do much for your AVR programming skills...
Architecturally, AVRs are fairly well-behaved. The biggest problem I've had is the fact that they're SO well-behaved, it's easy to get a false sense of security and overlook details that are different between them. Unfortunately, Atmel's datasheets seem to have the same general editorial philosophy as the first O'Reilly books (say it once, never repeat anything, and bury important details in the middle of otherwise nondescript paragraphs on page 183, without so much as a gray box or sidebar to call attention to it). However, everyone at avrfreaks.net is painfully aware of those documentation shortcomings, and when somebody gets snared by one of them, someone else usually notices within 5 minutes, sighs, yawns, and politely points them in the right direction. It's exceptionally rare for anyone to get flamed.
As far as robots go, AVRs definitely seem to be just about everyone's favorite 8-bit processor. 6809s are popular with some more advanced users (though many of them freely admit that they aren't quite sure why they used a 6809 instead of an AVR), and the 68332 is a longtime favorite at the high en
If you really wanna dive into AVR programming, you could also check out the Arduino.
It uses an AVR for the controller and doesn't require a PIC programmer, connects over USB to the computer, has support for Windows, Linux and OSX, and comes ready for working when you get it. The only part that is kinda limiting to people unfamiliar with programming is that it uses C++ as the language, but has a very simple instruction set, so the learning curve may be slightly steep for beginner programmers.
...spike
Ewwwwww, coconut...