what would be convenient to use for my (asrs) dc ,stepper or servo motors

im trying to make an automated storage and retrieval machine of library SYSTEM using arduino. And that would be a huge help if any one guide's me through this. i have been studying it for 4 days on internet diging around all that stuff .all i have done is difference between unipolar and bipolar motor and we need some motor driver to drive our motors and need external voltage supply to run them efficiently.
here comes the questions
1.to drive 4 stepper motors(if required) . do i need 4(four) ULN2003 for it.
2.THERE ARE ALSO SOME ADAFRUIT SHEILDS I HAVE SEEN WHICH ARE REALLY EXPENSIVE AROUND 20$ FOR 2 MOTORS.
3 KINDLY GUIDE ME AS IM NEW IF YOU CAN PROVIDE ME A LINK OF A THREAD THAT CAN HELP . PLEASE DO SO AS WELL.
4. and DC motors can return the distance it has covered as i am using line following robot in my project . thank you :o :o :o :o

You need to tell us what stepper motors you propose to use. AFAIK the ULN2003 is a suitable driver for the small unipolar 28BYJ stepper motors - but I have no idea whether they would be suitable for your project.

If you are not using 28BYJ motors then post a link to the motor datasheet.

Driving 4 ULN2003s would require 16 I/O pins so you would need an Arduino Mega.

AFAIK the Adafruit shields are intended for DC motors - and I don't think they are suitable for unipolar stepper motors at all.

If you use bipolar stepper motors with specialized steppper motor drivers then each motor will just require 2 I/O pins for step and direction.

These links may help
Stepper Motor Basics
Simple Stepper Code

I don't understand your Question 4

If you want an answer to the question in your title (stepper vs servo) then you need to explain how the motors will be used. A diagram of the proposed mechanism would be a big help.

...R

thankyou robin for replying .i read your links and they are really informative .but i think i should explain my project more exclusively .p.s it would be hard for you to understand as my english isnt good .
project porpose
1.it is a LIBRARY BOOKS robot which runs by phenomena of line following robot.
2.it will carry around 2 books at a time to perform either of the actions (which are store book, retrieve book which has been picked from isolated pick and drop station AND VICE VERSA) .
3.so the question arises how would i do mapping of the 24(rowscolumns back to back wooden book racks). i came up with a idea ,to make robot reachable on the specified rack location position here it is ,i would sync or measure each rotation of motor with the length of the line which is supposed to be followed.
imean if 1 rotation is equal to 150 cm then the shelve on 300cm would need 2 full rotationsu[/u] and for every book i have stored a pre-calculated value in the database table.
4.so now here comes the tricky part !i dont know which motor is supposed to be used in your thread you told every thing about small stepper motor and i dont exactly know the options available. As you are a experienced person. tell me ,that which parameters should i take into acount in choosing a motor sir .
in my scenerio . the load of 2 books could be maximum 4kg(assume).and as it is wireless robot it will also require a audruino mega wifi interfaced module weight and battery and chasis weight . it would be around 9 to 10 kilogram robot.
5.to keep and retrieve a book from a shelve i need a palette . and that pallete itself require a motor
6.imsorry for taking that much of your time ,but im clueless.
7.as from my previous post (on 4rth question ) i was trying to ask that can i give position of strator to rotate upto that limit and feedback its value . i assume not because in ur thread you told that for position stepper motors are cool and servo for feed back purposes . but i think the surplus torque would not be much in my case as the robot will not move too fast,which will exclude any missing if the speed is accelerated and decelarated correctly to hold the correct position. :frowning: :frowning:

More than ever, a diagram of your proposed robot is required to make sense of your description - and, by the way, your English is fine, it is just that the subject is complex.

Photos of some simple pencil drawings of the proposed machine will be perfectly adequate, and don't worry if you are not an artist.

...R

Hi,
Welcome to the forum.

Can you tell us your electronics, programming, Arduino, hardware experience?

Thanks.. Tom.. :slight_smile:

ok i will try to sketch some and reply you soon ..