Robotics 'half' beginner. Any help appreciated

Hi there
I'm a software developer delving into robotics, something I've always been interested in. I would be interested in any of your help or
experiences in this journey of expense....:-). Any help is greatly appreciated.Are you sitting comfortably?
1) The bits I know about....
I have a VIA ITX m10000 board, with PW60 DC-DC converter and a nice 12v battery. This is running win98 with .net framework off a Compact flash card. I can write any C# software needed to run guidance etc.
2) What I'd like to do. I'm considering buying a Rogue ATR Base unit to base my 'robot' on. (http://www.roguerobotics.com/index.php?module=pagemaster&PAGE_user_op=view_page&PAGE_id ). Once mounted i'd like initially for my ITX to be able to drive the beast, with perhaps the addition of some 'sensors' for collison. Later on maybe a webcam for fun etc.
3) What I don't know... I know very little about electronics but am a keen learner.
a)I want to understand how I can get my ITX board to communicate with 'motors' and 'sensors' etc. I've read a little about 'H-bridges' but haven't a clue about such things!
b)If I have motors that require 6volts, and my Battery is 12V, do I need a 'resistor' or something to cut the voltage in half? (sorry for my ignorance). If so how do I calculate the 'ohms' etc :-)
c)Has anyone any experience with this ATR BAse kit or is there another alternative
As I mentioned, any help appreciated
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The base you've selected seems way too small. I didn't notice that they provide dimensions, but as the base is built on Tamiya's Track-and-Wheel set, it's probably around 4" wide by maybe 7" long, Your Mini-ITX board is close to 7" square, and you still have to find room for a 12 volt battery, the DC-DC converter, and any other electronics and sensors. Weight adds up quickly.
Jay Newman, who posts here, has extensive experience with building robots using Mini-ITX boards. Check out his posts. He keeps a blog of sorts of his building trials, and the mechanics he's used. His tracked bases are 4-5 times larger than this one.
Personally, I'd go with a base of at least 10" square, and IMO forget the tracks unless they are rigid. As weight increases, rubber-only tracks can stretch, then pop off the drive sprocket in a turn.
Before buying any hardware I'd suggest:
1. Get a good all-around book on robotics basics. I wrote one, and there are some others, like David Cook's Robot Building for Beginners, and Gareth Branwyn's Absolute Beginner's Guide to Robotics. Thumb through the books at a bookstore to see which one(s) suit your needs. Mine probably has the most about interfacing to PC electronics (though via a parallel port mostly), and I'll say now it's limited to just a couple chapters, because it covers several other electronics approaches as well.
2. Look into USB-serial and USB-parallel converters. You can then buy or build interfaces from these converters, as needed. These are easier to use under Windows, especially if you use a simple DLL in your C program.
3. Bone up on general electronics with a good book, or use Google to find the *numerous* Web page tutorials. You may only have one or two questions now, but as you get into this, you'll have dozens, and it's just better to educate yourself first with the basics.
4. Keep doing lots of searches on Google to see what others have done. It'll save you lots of time in not reinventing the wheel. More and more folks are using Mini-ITX boards for robots. Check out VIA's Web pages for their robot initiative stuff. They include some links to companies trying to make this approach commercially viable.
5. And most important: start with a low-cost ($100-150) basic robot kit that is programmed using a microcontroller. Get some experience with the smaller form factor. You may want to get a controller you can program in C. Check out Brian Dean's MAVRIC boards at bdmicro.com. His are based on the Atmel AVR chips, which can be programmed using free versions of C (gcc, and several others).
-- Gordon Author: Robot Builder's Bonanza Budget Robotics: http://www.budgetrobotics.com
rw wrote:

(http://www.roguerobotics.com/index.php?module=pagemaster&PAGE_user_op=view_page&PAGE_id ).
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Gordon, thanks for taking the time to reply. All comments are very useful.

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Gordon McComb wrote:

Well, yes. However, it doesn't seem that Walmart carries that 1/5th scale M5 Stuart tank any more. :(

Agreed.
Gordon's _The Robot Builder's Bonanza_ is still the bible for this hobby.

I don't think that they are shipping yet, but White Box Robotics are made for the Mini-ITX boards.
http://www.whiteboxrobotics.com/

I second this. It will be much less expensive and you'll be up and running faster. You'll also get experience with the basics. -- D. Jay Newman http://enerd.ws/robots /
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Sounds like you've got a good handle on the number cruncher for your robot. I'm about to buy an ITX board for my web-controlled robot.
You will need to get into microcontrollers for motor control, sensor feedback, etc. I prefer PICs (www.microchip.com) but Motorola and Atmel also make good micros. I program my PICs with C using the CCS C compiler. I think this may be the way to go for you since you already program in C. You will be amazed at what you can do with a $6 microcontroller chip.
I plan to interface my ITX board to my main PIC with RS232 serial comm.
BRW
On 22 Aug 2004 10:43:21 -0700, snipped-for-privacy@stringx.com (rw) wrote:

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Hi Bennet. Thanks for your reply
I have read about the 'PIC' controllers. I understand you have to write code for them and load this code onto the chip. However, as I already have a 'brain' (My ITX board), do I really need to get another smaller 'brain' to control the robot. Can I not do this direct? Any comments greatly appreciated.
Bennet Williams <> wrote in message (rw) wrote:

>(http://www.roguerobotics.com/index.php?module=pagemaster&PAGE_user_op=view_page&PAGE_id ).
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The PIC will give you some very important things that the PC cannot. For example: Dual PWM output for variable speed motor control Extremely fast I/O control - e.g. determine distance and speed from an encoder and control the motor with a PID loop. Accurate time measurement and generation.
After you get some experience with robotics, you will see that the above things are very important.
BRW
On 23 Aug 2004 12:46:02 -0700, snipped-for-privacy@stringx.com (rw) wrote:

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(http://www.roguerobotics.com/index.php?module=pagemaster&PAGE_user_op=view_ page&PAGE_id).
Then is is best to use ready made circuits that come with instructions how to control them from your software.

Resistor (brake pads) voltage (accelerator position). This would be like controlling your cars speed by applying the brake without releasing the accelerator pedal. There are circuits that will drop the voltage efficiently. No major loss of energy in the resistor (brake pads).

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Hi John
Thanks for your reply. Do you have any info on 'recommended circuits' ?

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(http://www.roguerobotics.com/index.php?module=pagemaster&PAGE_user_op=view_
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rw wrote:

Likewise for the most part.

OK, I have the M10000 and PW60, but I run Gentoo Linux on it. I like to use Java for robotic control.

(http://www.roguerobotics.com/index.php?module=pagemaster&PAGE_user_op=view_page&PAGE_id ).
I think that this base might be a bit small for the Mini-ITX system.
Zagros Robotics makes some bases that are large enough.
I warn you that batteries are either going to be heavy or expensive.

You'll also need some sort of I/O processor for dealing with real-time systems (motors, sensors, etc.).
Phidgets have some interesting USB devices.
http://www.phidgets.com /

If you don't want to build your own H-Bridge, you can use R/C Electronic Speed Controllers. You'll still need a device to sit between the computer and the motors/sensors.

You can try the motors at 12 V. Sometimes you can use extra voltage safely.
One thing I've learned: if the motors you have don't work, it's often cheaper to buy new motors. -- D. Jay Newman http://enerd.ws/robots /
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Thanks Jay and for everyone else for taking the time to reply
Yes I have just purchased a 12v 7.2ah battery. 2.5Kilo is a hefty lump! And I imagine that even this may not run things for too long. I've bought an ammeter just learned how to work out how to use it to determine current drain! I'm hoping my move to ommit a hard drive and use CF will help things somewhat.
I've had a look at Zagros Robotics. Very interesting, and I'm starting to think that a robot without tracks may be the answer for my first attempt. (Shame as I think the tracked robots look very cool, is there not an alternative tracked kit someone can recommend? Perhaps with many levels and one that can handle a few kilos of weight without springing off it's tracks :-) ). Otherwise I'll go for a wheeled one.
I looked at http://www.phidgets.com /. Great stuff! I like the look of this... http://www.phidgets.com/index.php?module=pncommerce&func=itemview&KID 93330060194.106.46.79&IID1
Gordon, can I assume that that item will more likely work with these http://www.budgetrobotics.com/shop/index.php?shop=1&cart9944&catW&
I hope so, as then I can drive my wheels more easily than I thought.
Thanks.
Jay. Do you have a website detailing your experiments? Gordon mentioned a Blog.
Thanks again

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Also, Gordon, I like the look of your Octobot II. Very good value, and I'm thinking with it's multilevels, I might squeeze my ITX on one level, and battery, camera and sensors on the others?
Your thoughts appreciated.
snipped-for-privacy@stringx.com (rw) wrote in message

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rw wrote:

I don't think that it is big enough.
I have the original Octobot.
There seems to be about a 4 lb payload and your battery alone is more than that.
Plus the Mini-ITX board is 7.5 inches by 7.5 inches aquare and is bigger than the Octobot base.
Now, if you were to get a Nano-ITX board and use higher density batteries you might get it to work. -- D. Jay Newman
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D. Jay Newman wrote:

This is correct. The Octabot is suggested at no more than four pounds total weight, and the base itself weight one pound. RW's battery alone is 5.5 pounds.
-- Gordon Author: Robot Builder's Bonanza Budget Robotics: http://www.budgetrobotics.com
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rw wrote:

I get a couple of hours from a 9 volt SLA battery. This runs all my electronics.

Qute a bit. I'm mvoing to a 70 amp-hour battery when I go for a real hard-drive.
I will admit that I have to mount some of my development directories via NFS.

I like tracked robots also but as Gordon says, large tracks are non-trivial. The R/C tank I'm using has tracks which are composed of small individual segments.

http://www.phidgets.com/index.php?module=pncommerce&func=itemview&KID 93330060194.106.46.79&IID1
Yes. I have tested this on one of Gordon's kits, but the PhidgetServo4 only provides power to only a single servo, unless you provide the extra power.
The "blog" is my URL at the end of this post. -- D. Jay Newman http://enerd.ws/robots /
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Thanks again Jay and Gordon.
Ok so it looks like I'll have to lay out some cash and go for the Zargos beast for my first attempt. Better get saving! (unless of course Gordon expands his excellent range for a larger based kit for ITX users? hint hint :-) )
Anyway, I realise you guys are into your linux, but just for info for others I've managed to get win98 on a 512 CF card with 350mb to spare. Check this http://www.litepc.com/98lite.html . Plenty of space for my .Net app, gonna try using Speech SDK see if I can get the blighter talking before I can afford him moving.
Also I think I'll play around with the USB stuff and grab a copy of Gordons book.
I enjoyed reading your blog Jay, good luck with Stuart. I think a tracked vehicle may be a my second or third robot perhaps?

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