Pages: [1]   Go Down
Author Topic: Salvaged from Scanner: What kind of motor is this?  (Read 1012 times)
0 Members and 1 Guest are viewing this topic.
Los Angeles, CA
Offline Offline
Newbie
*
Karma: 0
Posts: 5
View Profile
WWW
 Bigger Bigger  Smaller Smaller  Reset Reset

Hi Everyone,

Just took apart a Canon LIDE scanner and am trying to identify the motor. Being a scanner, one assumes that it is a stepper, but beyond that, how can one tell if it is a unipolar or bipolar motor? I searched online for image references to differentiate but couldnt come up with anything.

Beyond that, is it possible to control this with the arduino without an intermediate driver? Checked the libraries on the arduino site and they seem to indicate the need for a "H-Bridge" (bipolar) or a "Darlington" (unipolar) . Is there any work around for this, or why is it necessary?

And forgive this last simple question: alot of posts say it is best to have an external power supply for the motor, but also that too much power will fry it. What would one use to modulate the power being fed to it? I mean this in the simplest way: in my mind, external power supply means hooking it up to a 9v battery or simply plugging it into the wall (this sounds like a bad idea...)

Logged

-lenn

Global Moderator
Boston area, metrowest
Offline Offline
Brattain Member
*****
Karma: 533
Posts: 26951
Author of "Arduino for Teens". Available for Design & Build services. Now with Unlimited Eagle board sizes!
View Profile
WWW
 Bigger Bigger  Smaller Smaller  Reset Reset

Can you read any markings on the battery at all? Does it just have 3 connections, or a 4th that is not visible in this picture?
Logged

Designing & building electrical circuits for over 25 years. Check out the ATMega1284P based Bobuino and other '328P & '1284P creations & offerings at  www.crossroadsfencing.com/BobuinoRev17.
Arduino for Teens available at Amazon.com.

Los Angeles, CA
Offline Offline
Newbie
*
Karma: 0
Posts: 5
View Profile
WWW
 Bigger Bigger  Smaller Smaller  Reset Reset

It has 4 connections. Does that mean its a bipolar?
Logged

-lenn

Dubuque, Iowa, USA
Offline Offline
Faraday Member
**
Karma: 46
Posts: 2501
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset

With four wires it has to be bipolar.

First step would be to find the continuity between the four wires. That should break it into two pairs (two coils).

If the resistance in each pair is 125 ohms or more (5V / 40ma max per pin = 125) then you can drive it directly from the Arduino's pins. If not you'd need to set up a basic transistor circuit so you can use more than 40ma or add a resistor to one of the lines of each of the coils.

The Stepper library would handle the rest for you. If the stepper doesn't turn properly then reverse the connections for one of the coils.

Logged

Topsham, Vermont USA
Offline Offline
Edison Member
*
Karma: 33
Posts: 1906
... in The Woods In Vermont
View Profile
WWW
 Bigger Bigger  Smaller Smaller  Reset Reset

Hi, With a bipolar motor you need to be able to reverse the direction of current flow in each winding.

Some stepper and motor info here:  http://arduino-info.wikispaces.com/TUTORIALS
Logged

Regards, Terry King terry@yourduino.com  - Check great prices, devices and Arduino-related boards at http://YourDuino.com
HOW-TO: http://ArduinoInfo.Info

0
Offline Offline
Shannon Member
****
Karma: 206
Posts: 12062
Arduino rocks
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset

I certainly wouldn't run it directly from the Arduino pins, its an inductive load.
Logged

[ I won't respond to messages, use the forum please ]

Pages: [1]   Go Up
Jump to: