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These folk:

http://www.parallax.com/

are in the business of making small microcontroller projects easy, quick and fun. Something like a member of their Basic-stamp family would be pleasantly overkill for your needs. They can convert your temperature readings, valve closures, infra-red readings and such to a time-stamped serial data stream that your computers can collect. There's a large number of good books on how to make the Basic Stamps do all sorts of cool stuff. So if you spend the money there, you'll be building a working system from cookbook instructions.

With externally actuated valves my favorite sensor is the hall-effect sensor (available at the site above). It's corrosion resistant, doesn't wear and is not angle sensitive. You glue the cute little magnet where it will fit, and the sensor where it will be close to the magnet in the on-position and Viola!

When you want a low cost solution, and to make thousands of them it's hard to beat the Atmel ATtiny series of microcontrollers for low power/cost and high reliability.

Agreed then!

I'm glad you know your ICs, that's very useful. I'm not familiar with what's out there, but I have a handle on using them. This one looks really good. The price is going up now though...
-- HM55B ($30)
-- Basic 2 Microcontroller ($50)
-- Carrier Board to test the circuit (either Serial or USB) ($65)
-- Other equipment (USB or serial cable + wires + 9Vs) (~$20?)
** Total Estimate: $165

Even though it's a lot pricier, this setup looks the best to me. The 55B comes with detailed instructions, a downloadable configuration program, and a free graphical interface to check it.

Once it's configured, the programming should be simple. Sample the angle from the board, and use a series of IF statements to turn on the correct motor:
IF Angle (less than) 20 Then
___HIGH 6 (puts the vibrator on pin 6 on)
___LOW (everything else)
ELSEIF Angle (less than) 40 Then
___HIGH 7
___LOW (everything else)
and so on...

Shouldn't be too hard... (famous last words?). ;)

Agreed then!

I'm glad you know your ICs, that's very useful. I'm not familiar with what's out there, but I have a handle on using them. This one looks really good. The price is going up now though...
-- HM55B ($30)
-- Basic 2 Microcontroller ($50)
-- Carrier Board to test the circuit (either Serial or USB) ($65)
-- Other equipment (USB or serial cable + wires + 9Vs) (~$20?)
** Total Estimate: $165

Even though it's a lot pricier, this setup looks the best to me. The 55B comes with detailed instructions, a downloadable configuration program, and a free graphical interface to check it.

Once it's configured, the programming should be simple. Sample the angle from the board, and use a series of IF statements to turn on the correct motor:
IF Angle (less than) 20 Then
___HIGH 6 (puts the vibrator on pin 6 on)
___LOW (everything else)
ELSEIF Angle (less than) 40 Then
___HIGH 7
___LOW (everything else)
and so on...

Shouldn't be too hard... (famous last words?). ;)

Agreed then!

I'm glad you know your ICs, that's very useful. I'm not familiar with what's out there, but I have a handle on using them. This one looks really good. The price is going up now though...
-- HM55B ($30)
-- Basic 2 Microcontroller ($50)
-- Carrier Board to test the circuit (either Serial or USB) ($65)
-- Other equipment (USB or serial cable + wires + 9Vs) (~$20?)
** Total Estimate: $165

Even though it's a lot pricier, this setup looks the best to me. The 55B comes with detailed instructions, a downloadable configuration program, and a free graphical interface to check it.

Once it's configured, the programming should be simple. Sample the angle from the board, and use a series of IF statements to turn on the correct motor:
IF Angle (less than) 20 Then
___HIGH 6 (puts the vibrator on pin 6 on)
___LOW (everything else)
ELSEIF Angle (less than) 40 Then
___HIGH 7
___LOW (everything else)
and so on...

Shouldn't be too hard... (famous last words?). ;)

This isn't a basic electronics kit, but Parallax sells some starter kits with their BASIC Stamp microcontroller. They have a built in breadboard and some basic components. They have a large number of excellent manuals online which can be downloaded for free. Download some of the manuals and/or school curriculum to see if it might meet your needs.

This isn't a basic electronics kit, but Parallax sells some starter kits with their BASIC Stamp microcontroller. They have a built in breadboard and some basic components. They have a large number of excellent manuals online which can be downloaded for free. Download some of the manuals and/or school curriculum to see if it might meet your needs.

This isn't a basic electronics kit, but Parallax sells some starter kits with their BASIC Stamp microcontroller. They have a built in breadboard and some basic components. They have a large number of excellent manuals online which can be downloaded for free. Download some of the manuals and/or school curriculum to see if it might meet your needs.

---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.

Too true, though I was thinking more on the lines of basic circuits, usage of a serial port, parallel port, and other simple older computer functions. I can think of some nifty projects for parallel and serial: Make your own game controller, sending text to those propeller-led text devices (and making it), designing from schematic a mp3 player for an altoids tin. And just look at all the projects that are rat shack part listed so it's easy to order and build.

And to mention building boards, how about teaching soldering technique? My dad can microsolder with a standard iron and a small tip. For a while, he was modding PSX's (yep, the little cpu pads)

---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.

Thats the problem, I tend to think these are too complex for high schoolers, at first. If the school doesnt have any tech classes like this, going into microcontrollers would be a mistake. Legos would be a good start, and then you could teach analog, then perhaps in the next year, digital. There's just soo much stuff you could concentrate on that has much value. Analog would teach these kids about signal and how it flows and is modified. Figuring it out would also require use of a oscilloscope, and would take quite some time.

---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.

No, teaching basic EM theory would be best, in that they could tether any means of communication to talk to their circuits. Once you have an input path, all neato things are possible. We can do 1-wire, serial, usb, radio, ir/photoresistor, led, and a few more types on the cheap.

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've also used the Parallax boards and I have to agree that they are the best for simple robotics and teaching low level computing in the classroom.

Personally, I would suggest using their Java based Stamp, only because your students would not only be learning robotics and electronics, but also a standard language in use everywhere today.

Their other controllers use a language much like BASIC but is unique to the Parallax hardware, not much value there.

Cheers!

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.

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.

On an egg...

the PIC's not bad if you use the right C compiler (you can use Asm too, if you're a stud), but for the beginner, there's nothing like the BASIC Stamp.

yeah, it costs $50 compared to the $2-10 you'd spend on a PIC. you'll get that $40 back after you do something in 15 minutes that would have taken a couple of hours in PIC asm. (I have nothing against assembly language but the PIC's instruction set is very, very slim -- you can't even compare two bytes without having to compare two bits, eight times.)

anyway, get a BS and get going. the rest of electronics can be summed up as V=IR; 70% of electrical engineering is just learning how to apply that equation everywhere you look.

While Z80s are cool, some people prefer microcomputers with RAM, ROM and I/O integrated on the IC. For example:

Microchip or
Atmel

or a small board level device like:

The Basic Stamp

A very cool supplier of microcontrollers and accessories is:

Sparkfun

And the usual suppliers:

Digikey
Newark
Arrow
Mouser

The Parallax Boe-Bot kit and included book is a good kit for the beginner. The kit is about $150 USD.

Who ever wrote this article sure chose his words to make it sound expensive. He made it sound as if you have to buy that Pioneer robot for $40,000 in order to use it.

That's simply not the case. You can develop for a wide range of robots with this from the Parallax Boe-Bot, Lego Mindstorm NXT and Roomba all the way up to those expensive robots for $40,000 or more. You can even build it for custom robots based on little pics like the BASIC Stamp computer and others similar to it.

The beauty of this package is that you can program it visually (using the Visual Programming Langauage) or in C# or VB - depending on your skill level.

Bill

Who ever wrote this article sure chose his words to make it sound expensive. He made it sound as if you have to buy that Pioneer robot for $40,000 in order to use it.

That's simply not the case. You can develop for a wide range of robots with this from the Parallax Boe-Bot, Lego Mindstorm NXT and Roomba all the way up to those expensive robots for $40,000 or more. You can even build it for custom robots based on little pics like the BASIC Stamp computer and others similar to it.

The beauty of this package is that you can program it visually (using the Visual Programming Langauage) or in C# or VB - depending on your skill level.

Bill

I started with the . It's not perfect, but the 2nd edition helped a lot, and the projects are decidedly garage oriented.

Lego Technics sets got me started with mechanics at a young age, and the book (my yellow covered, dog eared, marked up 1st edition) pushed me the rest of the way. I grabbed the books on the Rug Warrior from the MIT crew as a second step, though I didn't pursue them.

The Parallax BOEBot is wonderful too. it's a lot more expensive, but it's an all in one kit that can get you a light reactive robot in an afternoon.

I am a parent of a 10 year old boy and 7 year old girl. My son and I coded our first BASIC stamp robot (Parallax Boe-Bot) last year. He has since taken an interest in his 300-in-1 electronics kit, and modifying the games he plays on his Knoppix for Kids distribution (he often runs that over the Fedora and Ubuntu distros also available in the house). A few days ago he asked me how a web site works, so I am going to teach him a little html this weekend.

My daughter plays the piano and has access to a MIDI keyboard. She and I have had a couple conversations about MIDI and was fascinated by the paper pipe organ we built. I just started designing a small, networked, pipe organ with the hope of demonstrating some programming and networking concepts to her.

We have also built rockets, a trebuchet, and even kept bees together. I plan on dusting off my homebrew equipment soon.

Children are never bored by the possibilities of technology. They need only to be exposed to something more than closed and highly polished consumer products. Even THAT is a wonderful lesson in repurposing if there is a hack around who cares to show them.

http://www.parallax.com/detail.asp?product_id=2882 3 and http://www.mini-box.com/VIA-NL-10000E-Nano-ITX-Mot herboard and http://gcc.gnu.org/.

I played with the Mindstorms kits for a while in one of my EE courses. It was fun and fairly simple, but, as tends to be the case, cut out a lot of the low-level stuff that makes robotics and engineering so fun. I have been planning on picking up the BASIC stamp kit sometime, so that I can play with a bit more, have greater control, and probably spend more time debugging my projects. Mindstorms is great, NXT sounds pretty cool, but I will take my BASIC kit, I do believe.

If you enclose your gear in an airtight box it still might get colder than you would like. You can just put a light bulb in the box (wattage would vary depending on the size of the box) attached to a thermostat. Light bulbs work just as well as a heating coil, and you can use photoresisters to instrument the box and tell you when the bulb burns out.

You can even run the thing with a digital thermometer, BASICstamp (and board) and photo-resister, you can run the whole thing
from an embedded system and be comfortable with the reliability, even. And you get a neat project.

http://www.parallax.com/html_pages/products/compon entshop/sensors.asp

I mean, seriously - it can't be the servos, sensors, mechanical linkages, or plastic "body parts". Lynxmotion's Robonova only costs $1000.00 for a kit, and that includes digital feedback servos. I know for a fact that the accellerometers, force sensors, and electronic gyros don't cost that much, we could probably safely say another $1000.00 (and that would likely be a high estimate, although I haven't been able to find pricing on miniature 3-axis force sensors, but they are nothing more than fancy small strain gauges). If you wanted vision, you could add on a cheap CMUCam system from Parallax - something which doesn't seem to be a part of the HRP-2m. For an SBC of the size and power quoted (240MHz SH-4 processor, 32MB of RAM, business card sized, linux capable), I was able to find a few examples after a bit of googling for dev kits (of similar spec) for around $1200.00 (personally, I would stick with a cheapo desktop communicating with the 'bot via bluetooth or a similar wireless link, coupled to a servo controller, and maybe a Parallax Stamp or Propeller for management). Software is "open" (though not really "open source" - you need to license it), and free to download (for non-commercial use), so there isn't any cost there (unless, as another poster pointed out, there is a firmware issue - which I didn't research).

I just don't see how there could be justification for $7000.00, let alone $14000.00! As I attempted to describe, a similar robot with similar capabilities can be picked up almost "off-the-shelf" (albeit, from a few different vendors instead of just one) for almost half the price of the "low" estimate, while being generous with my estimated pricing. Likely, you could do even better - for example, using Lynxmotion's servo brackets plus lower-cost non-digital servos, you might able to build something like the Robonova for about 2/3's or so of the cost. If you made your own brackets from cheap alluminum, you could knock even more off the cost (though you will still pay for it in time to machine those brackets).

You ultimately "get what you pay for", so I wouldn't go too cheap - the Lynxmotion servo brackets and cheaper non-digital hi-tec servos would probably be the lowest cost (in terms of money, time, and aggravation) that I would be willing to spend, personally. However, there comes a point where you are just spending money to spend money - and for something like this, that point is about $3000.00 (give or take a few hundred), unless your biped is a fair amount taller than 14 inches or so. So, where is the price increase coming from for this machine? The answer is right in the article:

Much of the technology behind Choromet was originally developed for the HRP-2 Promet (pictured at right), a life-sized research robot marketed by Kawada, and costing tens of millions of yen (upwards of $170,000).

Can you say "recovery of invested funds" (by overcharging buyers of a 'toy')?

I mean, seriously - it can't be the servos, sensors, mechanical linkages, or plastic "body parts". Lynxmotion's Robonova only costs $1000.00 for a kit, and that includes digital feedback servos. I know for a fact that the accellerometers, force sensors, and electronic gyros don't cost that much, we could probably safely say another $1000.00 (and that would likely be a high estimate, although I haven't been able to find pricing on miniature 3-axis force sensors, but they are nothing more than fancy small strain gauges). If you wanted vision, you could add on a cheap CMUCam system from Parallax - something which doesn't seem to be a part of the HRP-2m. For an SBC of the size and power quoted (240MHz SH-4 processor, 32MB of RAM, business card sized, linux capable), I was able to find a few examples after a bit of googling for dev kits (of similar spec) for around $1200.00 (personally, I would stick with a cheapo desktop communicating with the 'bot via bluetooth or a similar wireless link, coupled to a servo controller, and maybe a Parallax Stamp or Propeller for management). Software is "open" (though not really "open source" - you need to license it), and free to download (for non-commercial use), so there isn't any cost there (unless, as another poster pointed out, there is a firmware issue - which I didn't research).

I just don't see how there could be justification for $7000.00, let alone $14000.00! As I attempted to describe, a similar robot with similar capabilities can be picked up almost "off-the-shelf" (albeit, from a few different vendors instead of just one) for almost half the price of the "low" estimate, while being generous with my estimated pricing. Likely, you could do even better - for example, using Lynxmotion's servo brackets plus lower-cost non-digital servos, you might able to build something like the Robonova for about 2/3's or so of the cost. If you made your own brackets from cheap alluminum, you could knock even more off the cost (though you will still pay for it in time to machine those brackets).

You ultimately "get what you pay for", so I wouldn't go too cheap - the Lynxmotion servo brackets and cheaper non-digital hi-tec servos would probably be the lowest cost (in terms of money, time, and aggravation) that I would be willing to spend, personally. However, there comes a point where you are just spending money to spend money - and for something like this, that point is about $3000.00 (give or take a few hundred), unless your biped is a fair amount taller than 14 inches or so. So, where is the price increase coming from for this machine? The answer is right in the article:

Much of the technology behind Choromet was originally developed for the HRP-2 Promet (pictured at right), a life-sized research robot marketed by Kawada, and costing tens of millions of yen (upwards of $170,000).

Can you say "recovery of invested funds" (by overcharging buyers of a 'toy')?

Nintedo could hold little development competitions (Sony did that once with the Yahorzee, I remember playing the games on a PlayStation Underground CD) which fosters talent, good will, etc.

I don't understand why these companies don't do this. Why not do it for the older consoles? Now that the PS3 is out (hypothetical), release a dev-kit for $100 that lets you make PS2 games (I know you can do it with the Linux kit, but they need better libraries instead of "here is the chip manual, figure it out" which is where I understand the Linux kit puts you).

And if they don't sell the console at a loss (or sell a "developer" version for an extra $50 or something) then they will only make money off the people who buy the console to develop for it.

All I'm left with right now is waiting for Parallax's Propeller chip (read about it here) which looks like a great little console on a chip to me.

Well, weather balloons are only meant for initial testing phases of the robots and ribbons and such. Also, weather balloons can go ~21 miles up. While that's significantly less than the total 62,000 miles, 21 miles still provides significant challenges for current technology to overcome.

What you need is a device like a Basic Stamp which you can connect to the Mac (possibly using a USB->Serial adapter). You can then connect that to a relay board that can switch high voltages such as this. Now you install a pair of flat metal plates on the seat your kids sit on when using the computer and hook them up to a relay on the relay board. Now you can write a simple app that gives your kids a 110V shock after a designated time. My kids complained at first because they said it didn't give them much warning. So later I added a pair of step down transformers to give them shocks at 30V and 60V before going for the big one. Let me tell you: I've had no problem with computer overuse.

What you need is a device like a Basic Stamp which you can connect to the Mac (possibly using a USB->Serial adapter). You can then connect that to a relay board that can switch high voltages such as this. Now you install a pair of flat metal plates on the seat your kids sit on when using the computer and hook them up to a relay on the relay board. Now you can write a simple app that gives your kids a 110V shock after a designated time. My kids complained at first because they said it didn't give them much warning. So later I added a pair of step down transformers to give them shocks at 30V and 60V before going for the big one. Let me tell you: I've had no problem with computer overuse.

The Gumstix would be the most robust option but that's a few hundred dollars.

You could consider the SitePlayer which is put together by a company that also does basic stamp clones, or a Parallax PINK.

These development kits run about $100. The SitePlayer would be a good option if you want to make more than 1 because the actual module is only $30, however if you are only going to build one of these tools I would suggest spending the extra $100-$200 and get a Gumstix because you can simply do so much more (and Bluetooth and WiFi over CF is are options as well, which could be useful later on).

Yeah, I did read it. The part that stuck out to me was that the new sats were about 60 pounds heavier than the old ones. Now I understand that they couldn't have gotten all the new features in for only 60 pounds without modern technology. Still, I can't help but think that it could have been a lot smaller than that.

Then again, I'd like to see a day when we can create useful PongSats, for this stuff but I supposed that won't be happening anytime soon. (Especially not when you need a large tranceiver!)

Why don't we go with instantly....

I picked one up a couple of weeks ago when the store was donating their gross income for the day to a Katrina fund. It's advertised in Make vol 3.

Ebay is your friend.

Also consider going with PICs, Basic Stamp, SitePlayer (a webserver on a chip), the BugBook books and hardware, 8085-based systems, or some other simplistic frameworks.

A year or so ago, I was lamenting how complicated (and unapproachable) systems had gotten, and a friend proved me wrong when he pointed toward some similar set of suggestions. There are a zillion interesting ways to learn practical/basic digital electronics now, rather than fewer. And the results can be delightfully cheap: simple atmel pic's sell for a buck or 2, can be programmed by some funny homebrew parallel/serial port interfaces that are equally cheap, etc.

And then there's USB, digital A/V, etc.

Depending on what aspect of pc design (memory, buffering, hardware I/O, signals/timing, computation, real-time circuits, homebrew SCADA, animatronic/smart toys, robotics, or whatever), you can either go retro using modern equivalents to old hardware or do enough to learn concepts and then fast-forward to the newer tools.

Sounds like a good course... I wish I had something like that when i was in highschool :). Anyways, for parts, http://digikey.com/ is probably the best. You might also want to check out http://jameco.com/. If you're teaching robotics, you'll probably want some simple MCUs to teach basic microcontroller concepts with. I would suggest a simple PIC micro from http://microchip.com/ or better yet a BASIC stamp from http://www.parallax.com/

The FTDI FT232BM is what you're looking for. RS232 to USB, with drivers for Windows, Mac, and a linux usbserial driver to boot. $5/chip in one-offs. Great chip for interfacing with any serial device, microcontroller, etc. Mouser sells this chip on a nice backpack board with all the external logic you need -- just connect the power, tx, and rx, and you're done!

Mouser won't sell it to you, but Parallax will sell you the chip itself. If you want a commercialized version, the Belkin USB-Serial converters are based off of this chip (and though the parts cost $CDN15, minus assembly and casing, somehow they retail for $CDN45!)

Check out the Basic Stamp from Parallax. There are kits that use it to teach logic, programming, electricity/electronics, etc. Price is good (radio shack has the whole kit for $79 bucks - it's called the "What's a microcontroller" and it comes with everything you need to do a bunch of nifty experiments). User forum support is pretty good too: http://www.parallax.com/ Dan

It actually sounds like quite a nice little embedded system, a kind of grown-up Basic STAMP.

• 384K of SRAM, single cycle access
• 27 MHz ARM7TDMI
• FBGA chip form
• ~450,000 instructions per second
• 4MB non volatile flash
• 1.8-volt core, 3.3-volt I/O
• 32768 Hz real-time clock
• 32-pin pinout, including 24 GPIO ports multiplexed with other functions (8 VTU ports, dual serial ports, SPI, and USB port)
• SPI and I2C interfaces

I assume FBGA is a typo for FPGA. This thing sounds suspiciously similar to one of those standard FPGAs with a built-in ARM7 core.

It actually sounds like quite a nice little embedded system, a kind of grown-up Basic STAMP. I expect that the .net VM is in ROM; on start-up the FPGA is probably bootstrapped from it. I wonder if it would be possible to replace it with a real operating system?

Lego Mindstorms can be a great way to start. But it can be limiting. It comes with only 2 motors. It can control only 3 motors and have 3 sensors. The programming environment can be limiting too, but there are other options on the web to help.

If you think your friend would be interested in something a little more complex, I can point you to some other resources...

There are some robot kits on the market. A pretty good one is: SumoBot Robot ~$150

Or you could get a platform and controller board seperately:
Tracked Motorized Platform ~$60
Controllers The OOPIC II Starter package ~$70 is a decient starter

A number of hobby clubs in Colorado like the Atmel Atmega Microcontrollers for building custom robot board such as the DARC Board.

The Portland Robot Group has a lot of great information for people starting out with hobby robotics.

My robot blog with lots of pictures.

Lego Mindstorms is a neat way to start, but it can be a very limiting platform. For the most part you are limited to 3 sensors and 3 motors - and the base kit only comes with 2 motors.

If your friend would be happy with Lego robots, that would be a good choice. If you want to look at some kits that allow a lot more interation on more of the complexities, check out:
Parallax - SumoBot Robot ~$150

Also you could look at mixing and matching:
Budget Robotics - Tracked platform
Acroname - Controllers

There are other options, especially if you friend would be interested it doing more work from scratch.

-- Keith - My: Robot Blog Main Blog

Trusty 'ol HandyBoard
68HC12
Lego Mindstorm
8051 development board
Good 'ol Parallax

There are also chips/development boards from Microchip (manufacturers of PIC series of ucontrollers) and Atmel.

Most of the above DO NOT come with motors, sensors, base, wheels etc. However, these are not difficult to find at a nearby hobby shop.

For a little more challenge, get a DSP board (TI, Motorola, Analog devices etc). You can get a good new/used one for pretty cheap from eBay

That said, you can get a cheaper one. They are not as good, but... they're cheaper. Lynxmotion's Biped, or the less fancy Parallax Todler.

Think of your lawnmower as a BattleBot. You've got a drive system (wheels) and a "weapon" (the blade). Okay, it's not the greatest analogy, but we're talking about components of the same caliber, and I know a little bit about this type of robotics.

Building your mower from scratch would be something fun and geeky and not *too* difficult if you know how to weld and such. If you take this route, consider using battery power for the drive train and a small engine for the blade. I recommend electric power because it is easier to interface with a navigation computer and allows for easy reverse if you get stuck up against an obstacle. You could even use another electric motor for the blade. In any case, a good source of electric motors is NPC Robotics. They also have wheels you could use. I think a remote control system would be neat, even if you don't want to drive it around all the time. You could use it to guide the mower if it's "lost" or as an emergency shutoff from inside the house. A manual override feature would be cool to just drive it around for fun, too. Of course, this makes things expensive. But a neat way to do this would be to use an IFI Robotics Isaac 16. This system includes a radio and transmitter plus a BASIC Stamp computer that is easily programmable and allows the reading of 4 analog inputs and 8 digital inputs (sensors on the mower). This would allow you to have, for example, an "RC startup" button inside your house that would remotely trigger the mower to begin running, then use the programming features for automated mowing. It could be both RC and autonomous, really. With that system, you could use a couple of Victor 883 speed controllers to regulate your drive motors. There's also a spin controller that would be perfect for your blade if that were electric powered. Otherwise, a simple gas engine with a servo on the carburetor throttle would suffice for control of that.

If you don't choose to go with this (very expensive but neat) RC setup, you could use a much simpler BASIC Stamp. This is the "brain" of the Isaac 16, but minus the radio and PWM signal drivers (for speed controllers, servos, etc.). They run a lot cheaper ($150 for a basic setup) and are still very easy to program (a modified BASIC syntax) but you would have to wire your own interfaces to speed controllers. This can be done, but I have no experience with it. In any case, the BASIC Stamp would allow you to connect various types of sensors that you could use to gather data and then modify your path accordingly. The Stamp is probably a better choice than a Mini-ITX or similar because it is cheap, not overkill :-P and has all the programming tools set up, ready to go, and designed almost specifically for robotic applications.

So check some of that out. I hope that helps if you're looking to build something from scratch.

Oh yeah, if you're concerned about powering an electrical system for long enough to mow your lawn, a few 12 volt lead-acid batteries of the type used in motorcycles or smaller car ones will likely suffice. I believe they can deliver around 14 Amp-hours or so.

I'm surprised no one has suggested a Basic Stamp. Personally I have stopped using them because I started needing more power on my projects, but for simple robot platforms, they are a pretty good teaching tool. If you get a BS2 kit with one of the books to go a long with it, you'll basically have everything you need to get started. You wont have laptop control, but if you are interested in controlling it with a laptop I would try rentron and get some transmitters/receivers and play with making it wireless. The basic stamp is limited in it's ability, but its hard to find any other kind of robot kit that comes with an entire curriculum like anything from parallax does.

A 1.8Ghz Duron ($44) at pricewatch.com contains more complicated electronics than . . . say a . . . basic stamp 2 microcontroller ($49). Why is the more complicated elctronic device more expensive? Economies of scale, market size, and competition, all weigh in on the pricing system . . . And all this can be boiled down to supply and demand.

Simplicity of electronics is one factor, but not a single determining factor in price.

I've been using the BASIC Stamp Tools for Linux for a while now. It uses the (unfortunately) beerfree parallax pbasic tokenizer so. If you don't want to use the BS, the Atmel AVR series is well supported by open source software, and really fast as well (native code vs. interpreted).

So which Atari hacking are we talking about? Arcade PCBs, 2600s, home computers, Atari Calculators, Atari UNIX boxes [!]. what?

Regarding hardware hacking in general, I think one of the best ways to get started is with a BASIC Stamp, like from parallax. It really lets you expore the interface between software and hardware.

I kind of wish the review gave me a better feel for the book. I'm getting better in my hardware, but I'm not beyond a good textbook to lean on for some things.

The site is already down but there is an example of it in a VW: here

TIP: If you buy these through Parallax there's a volume discount that cuts the price down to about $170.

So here's the story: We are three nerds (Isaac, Damon, and Reid). Upon Damon's return from MIT to our native quaint mountain village of Ashland, Oregon during winter break, he decided that the BASIC micro-controller he had just procured should be used in a high-speed flash photography lab. This was something Damon and Isaac had considered before, but not very seriously. Anyway, for this we also needed something moving or changing very fast, so we decided to build a bolt gun. Of course, bolt guns aren't very fun unless you can see, in great detail, the object they are hitting explode, so these two projects seemed like a match made in nerd heaven. With the aforementioned micro-controller, we simply had no choice but to build a flash timing mechanism to capture images of hot bolt-on-food action.

The mechanism works something like this: An air compressor is used to build up pressure behind a sprinkler valve. This valve is attached to a long PVC pipe which acts as the barrel of our gun. A button is hit, telling the micro-controller to open the valve, thus releasing the pressure and sending the waiting bolt hurdling forth at around 150 m/sec towards its suculent victim. When the bolt exits the barrel, it dislodges a piece of paper (thanks, Reid for the idea) which is blocking a beam of light. Once the paper is gone the light hits a photo-resistor, thus lowering the voltage output of a voltage divider, and triggering a binary input pin on the micro-controller. At this point the micro-controller counts to a number dictated to it by some DIP switches. We used a delay of 5 ms in most of our pictures. After this delay, the flash is triggered through a high-current relay. We simply set a couple of nice digital cameras (thanks, Damon's mom and Isaac!) to long exposures while the lab was completely dark, so all the cameras captured was the image at the time of the flash. This timing worked out so well in our lab sessions that we could determine where we wanted the bolt to be in relation to the unfortunate edible object in the shot by simply moving the morsel forward or backwards a few inches. The flash we used was a disposable camera that Damon gutted and soldered a relay into. Considering the speed of the bolt when it exited the barrel, the flash performed quite respectably for a disposable. Anyway, that's about all there is to it, so have a look at the pictures. In some of them you can see the piece of cardboard used to block the photo-resistor flying by in the background. All pictures were taken in Damon's garage-lab (thanks, Damon's garage!)

Note: even though we're absent minded, we (gasp!) did consider our safety in doing this. We put a slab of old carpet behind the fruit we were shooting, in the path of the bolt. This way the bolt didn't go across the room, bounce off of various objects, and become swiftly lodged into our soft brains. If you try something like this, we highly suggest you block the path of your projectile in a similar manner, wear goggles, and don't sit too close to the end of the barrel, like Isaac did.

If you want any of these pictures in a larger format, take a look here.