unrelated stepper question

[magic]

I want to program a small stepper using a stamp, chip or other.

I have no idea where to get started as I also need to buy the parts. The stepper will turn a 2 inch pulley that lifts 5 ounces.

Thanks

[richards]

Driving a stepper motor is more complex than most people imagine.

The simplest method is to have the controller chip (Stamp, Atmel, Z-World, etc.) drive a stepper driver (Geckodrive G251, G201x, G203v, etc.). That would only require that you write a program that ramps the motor to get to the proper speed and that you pulse the stepper drive at the proper frequency with the correct number of steps.

A much more difficult method is to have the controller chip directly drive the FET chips that energize the motor's coils.

Keep in mind that programming a microcontroller can require a chip programmer and specialized software. The (obsolete) EMP-20 that I use to program Atmel 89Cxxx chips cost about $1,000 and the software that I use to write the programs cost another $1,000.

Building the circuit board can also be expensive. I use ExpressPCB, which is free, but it ties you to the board manufacturer. Their prices are reasonable, but expect to pay at least $90 for a small prototype and much more if the board is larger than 2" X 3".

There are a lot of stepper motor tutorials that you can Google. Once you've decided on the basic method that you want to use, if you're still convinced that you want to proceed, send me an email and I'll try to help.

[dana_swift]

Look at the site:

http://www.hobbyengineering.com/

for information on programming stepper motors yourself. There is a large community of people who work with robots as a hobby and they control steppers all the time. They have inexpensive and effective methods when the forces are small and the performance is modest.

A few web searches will result in all the information you need. Probably including source code examples and I/O circuits.

That should get you to the result you want with a reasonable amount of effort.

D

[myxpykalix]

knowing nothing about how to do what you want to do Mike and Dana seem to have a handle on it and the only thing that occured to me to ask is, will this stepper be something that works in concert with the stepper motors on the bot or is this for something totally seperate?

If it is in concert with the table wouldn't you have to have the same type/model to be in synch or compatible? Just something that occurred to me...

[jim_ludi]

Magic,

Take a look at this website http://www.taomc.com/home.html that Bill Young found years ago. This is a very interesting website that deals with, as the author says, "The Art of Motion Control" and how the author uses motion control to create art work for museums, etc.

Follow the link to "Educational Uses > From Bits to Bots Course" and see if this gives you some insight into using steppers for projects. And, take a look at some of the art projects/machines the author has created at "Educational Uses > Teaching Machines".

[Brady Watson]

Another option is to use a 'servo' from a radio-controlled car/plane etc. You can get them in many torque ratings, modify them for continuous rotation (intermittent duty) and control them precisely any number of ways.

Check out the Arduino Playground example: http://www.arduino.cc/playground/Learning/SingleServoExample

The Arduino is Make Magazine's universal electronic interface. It can do all sorts of good stuff. It's cheap - Less than $50 and there's lots of support out there to get you going. I believe that there is an interface or 'shield' for controlling a stepper motor as well, if you dig around a little.

-B

[bill.young]

Thanks for posting that Jim..I was just going to do it myself. Bruce Shapiro does some very neat things with steppers and will probably be at the San Mateo Maker Faire if you want to see what he does in person.

[magic]

Jack. This is for a magic trick. If I ever get off the internernet I can start making it.

Brady, I'll need it to rotate a number of times in both directions

I think my head is going to expode learning about this.

Thanks.

[Brady Watson]

Brady, I'll need it to rotate a number of times in both directions


A typical servo can be easily be modified for continuous rotation. They are very compact, have decent torque and if you go with the small arduino, the footprint of the entire package is much smaller than any stepper solution you are going to come up with...This is what you want if you want 'easy'.

-B

[jim_ludi]

Bill, now you've done it! I'd love to see what Bruce is doing. Is ShopBot going to be at San Mateo this year?

[billp]

Yup ! We'll do a Camp on the Friday ( May 21st) on the grounds of the San Mateo Fairgrounds, and then we'll also be doing the Maker Faire Sat/Sun May 22/23. More will be following soon as we still have a few Camps and the Jamboree between now and then...

[bill.young]

Hey Jim,

I haven't heard specifically that Bruce will be there, but he lives in the area and has been at every other one. So I'd be surprised if he wasn't there.

[magic]

I think I need to have someone else build what I want because I can't get a handle on all that info. It would be easier just to pay someone to tell me what parts to buy.... but someday in the future I can see many uses that I could learn about.

Thanks

[myxpykalix]

Not sure if this is relevent but it might be in the ballpark. If not you might make contact with someone who knows circuitry and motors and can help you.
BTW if anyone can identify the music on the video i'd appreciate it.

http://www.instructables.com/id/2-motor-control-joystick/#previewlink