Arduino?

[Kusha]

Well, I'm a sophomore and a month back I bought my first arduino after reading up about it at 2am since I couldn't sleep.

I've been designing a robot that would be a 3 motor 3 omni wheel, kiwi drive in cad.

My question is, is this a good starting point for me? I've played around with it with some old dc motors I took out of some CD drives. Learned how transistors and capacitors work. I'm currently looking for a good bluetooth module to attempt to get the robot I'm building controlled via android. Along with 3 good motors, some omniwheels and a ultrasonic sensor that will be mounted on an servo.


Am I putting too much on my plate, or is this a good goal and a good starting place for me?

[davidthefat]

I would say that it is a great project. I say go for it, what do you have to lose? Even if you "fail", you would have learned so much along the way.

[Kusha]

Originally Posted by davidthefat

I would say that it is a great project. I say go for it, what do you have to lose? Even if you "fail", you would have learned so much along the way.

You're right. But I just didn't want to get on a project that would
A) Never get done
B) Fail because I lacked the skills needed to finish the project.

But you're right, so far just experimenting with leds and motors and such has given me so much experience.

I guess the next step is to find some motors.

[EricH]

CD drive motors aren't good motors? News to me. Gear 'em right and they'll be pretty darn good. (Trust me on this. ONE CD drive motor geared down a little bit can get a 52-second time over a 20' course. That was at about 1/3 speed.)

I think a kiwi drive is a decent option for some offseason programming. It's a challenge, but there is some code around, I think, that can help you figure out
what you need to know.

[Kusha]

Originally Posted by EricH

CD drive motors aren't good motors? News to me. Gear 'em right and they'll be pretty darn good. (Trust me on this. ONE CD drive motor geared down a little bit can get a 52-second time over a 20' course. That was at about 1/3 speed.)

I think a kiwi drive is a decent option for some offseason programming. It's a challenge, but there is some code around, I think, that can help you figure out
what you need to know.

It doesn't seem to me that I can drive the design I want with cd motors.
I was planning to get some time with our mill and mill some plexi out in the form of two circles, one on top of each other and everything else wedged inside of there like a sandwich.

PLUS, I wouldn't know where to start with gearring a cd motor .

If I can find some good motors on amazon and get them shipped with prime, I could have an amazing weekend ahead of me. Besides the fact that there is a robotics meeting this weekend.

[EricH]

I'm not certain how it was done, but a small R/C type gearbox had the motor directly attached to it. I *think* the ratio was 16:1. Wheel on the output shaft. This was the extension/retraction motor, BTW. If I had to guess, the pulley was removed from the motor and a gear put on. You might also be able to pulley into the gearbox.

For a kiwi drive, you might want to consider a triangular base instead of a circular one.

As another option, go with VEX. Those motors look like small servos. It's also possible to use continuous-rotation servos.

[Kusha]

Originally Posted by EricH

I'm not certain how it was done, but a small R/C type gearbox had the motor directly attached to it. I *think* the ratio was 16:1. Wheel on the output shaft. This was the extension/retraction motor, BTW. If I had to guess, the pulley was removed from the motor and a gear put on. You might also be able to pulley into the gearbox.

For a kiwi drive, you might want to consider a triangular base instead of a circular one.

As another option, go with VEX. Those motors look like small servos. It's also possible to use continuous-rotation servos.

I was thinking about a triangular base with arms on each corner
each arm holds a motor, or I can just go with a regular triangle, I haven't made my mind up yet about the complete design.

Vex motors? Got a link?

And I have NO idea what you mean by continuous-rotation servos.

I'm still a newbie, this is how I want to get even MORE involved in robotics in general.

EDIT:
Are these the ones you're talking about:
http://www.vexrobotics.com/products/.../276-2181.html

Would they be powerful enough to do what I need them to do?


I'm going to sleep. Tomorrow I'll update with pictures of my cad designing. Hopefully Saturday I'll have some freshly milled parts ready and possibly some motors waiting for me to play with.

[EricH]

We'll start with the easy stuff.

Continuous-rotation servos: Servos are motors that will go to a given position and do their best to stay there. However, some folks make continuous-rotation versions, which look the same but rotate continuously.

Go with a regular triangle; the mechanical work will probably be easier. Also, look in CD-Media for some pictures of kiwi drives.

VEX motors: The VEX website is http://www.vexrobotics.com/; motors are under the "motion" category. Also note the omniwheels and other miscellaneous items...

Edit: Yep, those or their cousins in the same line.

[Kusha]

Originally Posted by EricH

We'll start with the easy stuff.

Continuous-rotation servos: Servos are motors that will go to a given position and do their best to stay there. However, some folks make continuous-rotation versions, which look the same but rotate continuously.

Go with a regular triangle; the mechanical work will probably be easier. Also, look in CD-Media for some pictures of kiwi drives.

VEX motors: The VEX website is http://www.vexrobotics.com/; motors are under the "motion" category. Also note the omniwheels and other miscellaneous items...

Edit: Yep, those or their cousins in the same line.

Ok, thanks for the help how about I update this thread tomorrow once I have some time thinking about the design and to see what you think?

[sanddrag]

It'll never work. I think you should just pack up all the hardware and send it to me for proper disposal. I'll send you a box with a prepaid label to put it in.

All jokes aside, it sounds like a great project. Be sure to post back letting us know how it goes.

[DonRotolo]

If you hit a roadblock - something that stops your progress - I advise taking whatever that subsystem is, and just default to some other solution that you know you can implement but is less than "ideal". Get it working with the lesser solution, and eventually you'll find a way to implement a better solution.

In other words: When you stall, default to "anything that'll work" until later.

Good luck, ask questions when you need to.

[Kusha]

Just thought this deserved a small update:

I went out to home depot and brought some plexi glass and some 3/8 plywood.

I'm going to build a prototype on a piece of plywood and then transfer it onto plexi glass.

Here's the base so far. I just started, and I'm trying to get .step files to import to autocad (For vex motors and such for prototyping purposes.)
(found an add-on that imports .step, but i can't get it to work)
After I can get .step to import I can get a proper prototype, for now this'll have to do.


Any suggestions?


I need suggestions for the motors, I need 3. Right now I'm looking at buying the vex motors mentioned earlier in the thread. I was wondering if anyone else has a better suggestion.

[sanddrag]

Originally Posted by Kusha

Any suggestions?

Download and install Autodesk Inventor. Much easier/better than AutoCAD.

[Kusha]

Originally Posted by sanddrag

Download and install Autodesk Inventor. Much easier/better than AutoCAD.

Ok, I'll download the trial and play around with it. I was downloading AutoDesk inventor fusion anyway for converting .step to .dwg

[Molten]

Originally Posted by sanddrag

Download and install Autodesk Inventor. Much easier/better than AutoCAD.

It really depends on the application. For some things, AutoCAD is better. It really depends on the situation. That said, Inventor is easier to learn if you are new to drafting.