Arduino?
 

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?

Re: Arduino?
 

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.

Re: Arduino?
 

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.

Re: Arduino?
 

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.

Re: Arduino?
 

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 :confused:.

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.

Re: Arduino?
 

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.

Re: Arduino?
 

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.

Re: Arduino?
 

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.

Re: Arduino?
 

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?

Re: Arduino?
 

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. :D

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

Re: Arduino?
 

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.

Re: Arduino?
 

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 :confused: (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.

Re: Arduino?
 

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

Re: Arduino?
 

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

Re: Arduino?
 

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.

Re: Arduino?
 

Ok, I'm waiting on my mentor to give me the product key for autocad and I will start working on a model. In inventor, since the trial does not give access to it.

Today one of our mentors gave me 6x 12" Cold Cathodes never opened from 2007's game, since we were cleaning out the shop/redoing it.

I was wondering how I can control these with an arduino/ how much this would affect battery life (one thing I haven't even thought about) Lets say I had 4-6x AA batteries powering this robot. Would it even be possible?


Also, what the heck do the little black boxes that the cathodes plug into do? I assume ground and 12v?

I've also got some plywood for testing the prototype on, and some plexi to mount the final product on.

Re: Arduino?
 

Normally, those cold cathodes were powered in groups of 4 off a single robot battery (or arena power). The black boxes are power and ground, IIRC. If you wanted to power them off an Arduino, you'd probably need to put in an extra power supply just for them--or have the Arduino trip a transistor as a switch.

Re: Arduino?
 

So here is the question at hand, should I bother with them? Or is it too much of a hassle

Re: Arduino?
 

The black boxes take 12 V DC and convert it to whatever the CCFLs use.
To control something that draws 'relatively large' power (more than a few milliamps) a transistor switch is cheap & easy, or use a small relay. IIRC the Arduino can sink or source about 20 mA on a Digital IO pin.

Re: Arduino?
 

The transistor would be the option I would pick. I've worked with transistors in powering a DC motor from a cd drive, so I have some small experience.

So now I know I can handle putting in a cathode.

The question remands what about battery life, would this basically kill off my battery life?

Re: Arduino?
 

Are you registered on the Autodesk Student Community? I believe you can get 3-year licenses of all their software titles.

Re: Arduino?
 

I haven't, what are the requirements?

Re: Arduino?
 

I believe any educator or FIRST Team mentor can register on the site, then send students a special link to register. students.autodesk.com

Re: Arduino?
 

WOO! Alright THANK YOU! This is amazing, I now have autocad mechanical activated, along with inventor activated.
Thanks!

Re: Arduino?
 

[excuse the double post here]
I need good suggestions for motors, besides vex. As I am a high school student with no job, please keep the price ranges low.
Good enough to power a 3 wheel 9" diameter kiwi drive robot.

Re: Arduino?
 

Seeing as you already have the CD-drive motors, you should be able to use those. Mounting and gearing, though, are for you to figure out (hint: glue might work pretty well for mounting, depending on type).

You could also check a local RadioShack to see if they have small motors--there are some decent ones, if you get the "hobbyist" type of RadioShack instead of the "consumer electronics" type.

Re: Arduino?
 

Your choice of motors depends on two factors: Speed and cost. Powerful (=fast_ motors are more expensive than less powerful (=slower) motors. CIMs are what I'd call "expensive" and the Denso window lifter motors can be had for much less.

CD drive motors are not a bad option.

I always keep my eyes open for sources of motors. On trash day look for things that might be useful. Most appliances have AC motors, not useful, but treadmills have large, powerful DC motors free for the taking. If you live in an area where they have cars, look for a salvage yard (aka Junkyard) - you can buy window motors for $5 each or less, maybe even free if you explain nicely what you're doing with them (the 'poor high school student building a robot' routine works well). Just learn how to get the door panels off a car, as they'd like for them to be in sellable condition when you leave...


You asked of the cold cathodes would kill your battery? Not much, they are not very power-hungry. Once you connect one, measure the current (you do have a multimeter, right? If not Harbor Freight sells then for $3)

Re: Arduino?
 

I have no idea how to gear them, but mounting wouldn't be that much of a problem. I have a radioshack near me, 5 minute walking distance I'll go tomorrow after school to check it out.

Your post gave me a great idea, I can go to a thrift store and check around for some rc cars without controllers or something of the sort. Thanks for the tips tho. I will go around and look for motors creatively.

I'm very skeptical about the cd drive motors working that big of a robot...
I'm all for it if you guys can provide me a little guidance. How would I gear up a cd drive motor?

As for the cold cathodes I decided that I will give it a shot once I get it to light up more than halfway using a transistor(still doing my research on it)

Re: Arduino?
 

Don't be too skeptical. ONE can drive an 8-inch, 3-wheel Arduino-controlled robot. http://www.youtube.com/user/SDSMTMec...28/hG9tZ9O60dA

How do I know it was a CD drive motor? I'm one of the guys who took a CD drive apart, raided the motors, and wound up using it for the robot drive.

Now, when you dig up that R/C car, raid the gearbox. The more R/C cars, the more gearboxes. Then you can tweak the powering/gearing to suit your motors.

Re: Arduino?
 

All I can say is wow. That's freakin' epic.

I'm really excited about this project now. I'll get crackin' soon, HOPEFULLY Tuesday I get to mill out a frame for this robot and get some kind of prototype running by the end of the week.

Re: Arduino?
 

Small update here. I've been really busy with AP tests. On Saturday after GEAR (my mentors' lego competition) (I'm refing there.) I'll be going out to goodwill and some thrift stores to see if I can find some old rc cars so I can harvest the motors.

I finally made v3 of my base. I know I haven't showed v2 at all but here's v3.



It needs some adjustments but I like the concept. I also have some handdrawn stuff too, but I'm too lazy to upload. I'll be documenting and keeping everything. I seem to be getting the hang of inventor. This project is awesome so far.

I've also been playing around with some variations with the cold cathode, I think I have away of powering it it fully, I just need to find a good 12v power source....

PS.. This is what my folder looks like http://i.imgur.com/i4pM3.png I have been working on it. Slowly but surely. Now that AP tests are over for me I'll start to speed things up

Suggestions on design?

Re: Arduino?
 

Provided you already have an Android phone, you might want to look into Google's new ADK as a method of programming, where you can physically hook the phone up to the board like a tether, or integrate it into the system itself. They say they have Bluetooth support coming soon as well, and if not, you can also use Amarino. Just food for thought.

Re: Arduino?
 

I don't want to pay 300bucks for the ADK. I'm going with Amarino. It's a bit outta my price range seeing as I'm going to thrift stores just to get old RC cars.

The adk is great and all, but no thanks.

Thanks for the suggestion tho

Re: Arduino?
 

http://cgi.ebay.com/Omniwheel-transw...ht_1081wt_1139

Are these good enough omniwheels? Or is there any better/cheaper ones I can buy?

Re: Arduino?
 

It reminds me of the end connector for the Tetra game pieces in the 2005 game Triple Play.
I'm assuming you understand those wheels are 1.2" (3 cm) in diameter. This won't be an outdoor bot... Other than that, those look fine for the price. Shipping's not cheap, but buy more than 3 'just in case'.

Re: Arduino?
 

I couldn't find anything cheaper :/ and I understand this isn't an outdoor bot.
I'll keep looking, but I'll buy more than 3 for sure.

Re: Arduino?
 

These are the motors I'm looking at:
http://www.fingertechrobotics.com/pr...rod=ft-spark16



and these are the motor mounts I'm looking at:
http://banebots.com/p/PB-M0031-BB



What do you guys think of these?