Motors for the robot in the tutorial

[Arislan]

It's a pain being here away from civilisation and wanting to build a robot. My question is, if I can't specifically buy motors for a robot, can I safely remove the motors from electric screwdrivers or windshield wipers and use that? All I want at the moment is to built that simple robot talked about on this site's first tutorial.
There is a store here that sells tiny step motors, but I don't understand them at all yet. They have two models:

Model 1 (Japanese made by OKI) for $45, step angle: 7.5º
feed: 24V
Torque: 0.03 Nm  (No idea what Nm is)

Model 2 for $35, step angle: 18º
feed: 6V
Torque: 0.5 cNm  (No idea what that is either)

For model 1 I can also buy an optional "power driver" whatever that is. Which one do I get?

I suppose I can get the wheels from some old toy.

Some people also say to get motors from floppy drives or vcrs, but aren't those supposed to be AC?

[Admin]

well a 24V motor wont work, cause putting 24V on a robot is a pain (a lot of battery weight)

the 6V one is ok, but somewhat weak (cNm is centi-newton meters, or newton meters divided by 100). the 18º step is poor resolution though, meaning it will work but be jerky.

one day ill write a good stepper motor tutorial, but the place holder page will sorta explain how they work . . .

the motors from electric screwdrivers and windshield wipers will work fine, but may draw a lot of power so you may have problems finding a motor driver. windsheild wiper motors run aroun 12-13.5V, and draw like 4A of current. your best bet will be the screwdriver motor.

floppy drives and vcrs, although they get power from AC mains, convert the power to DC to run. they probably wont be geared motors, and will be weak, so not very useful.

i would say hook up two powered screwdrivers by hacking the power wires to your bot.

[Arislan]

I will look tomorrow for a suitable motor, then, even if it turns out to be from a toy car. I want 2 motors and only have one electric screwdriver. Since electric screwdrivers are a luxury item here in the Land of the Lost, I will not take my only one apart...I thought I'd find more here for sale but they dont have them.

On the other hand, wiper motors are easy to find, and so are power windows motors. The problem is they are usually used and in need of some cleaning....

[Arislan]

Also, took apart a electric pencil sharpener...the motor turned out to be AC....sigh

[Arislan]

Today I took apart a dead scanner and salvaged some junk from it, including a motor.

The motor has a few gears on it, and a 4-wire small white ribbon cable with the topmost being light blue.

Behind the motor is a sticker that says:
EM-408
2090 1G.
SLC-42D004
Shinano Kenshi Co. Ltd. China

Is this a DC motor?

Anyway, I had enough to buy one stepper motor, a 23LM-C004. So that is coming in the mail this month.... said there the torque was 5kg.cm which I hope is a good thing.

[Handmixer.com]

The motor you described is a stepper motor.

[Arislan]

I emailed the company about it and got this:

Hello Arislan,

Unfortunately the motor you are requesting information about is
proprietary. We cannot release any information regarding this motor.
Please for give any inconvenience this may cause you.

Thanks!
*****
Shinano Kenshi Corp
Tel: 310-636-2214
Fax: 310-915-7304

Dang!!!

[Admin]

odd . . . how do they expect to sell a motor if they dont release simple information like torque or rpm? its not like we can just steal the torque or anything . . .

[Arislan]

I can only think it was custom made by them for Epson and they don't want Epson on their case.

That said, how do I supply power to it? There are 4 wires...and I have no idea on the pinouts...

[Admin]

Ehhh if you dont have a pinout, then just guess by randomly hooking up power/ground wires. You will notice a specific pattern will get it to rotate in a particular direction. Write up a chart of combinations. You can do this with a direct connection from a battery. I would guess it would have the same pattern as other steppers they sell . . .

To control it electronically you will need a stepper driver . . .

[Arislan]

Do i risk burning the motor? What voltage should I use? AA battery? 9v?

I'm trying with the battery of a portable drill, 9.6v.. connecting wires 2 and 4 cause sparks to come from the battery but no rotation. The other combinations using two wire do nothing. Should I be using more wires?

[Admin]

nope it wont burn out, zero harm will be done. unless it has control circuitry already attached to it, which i doubt . . .

6V battery should be fine, anything that can apply maybe ~300mA of current. when you do a connection, the motor rotates the resolution, then stops. if resolution is 1.8 degrees, then it rotates that then stops. then you need to do another combination for the next step.

so one wire should be ground, the others are power. sparks probably mean you are shorting the battery somehow . . . ehhh im definitely no stepper expert tho . . .

[Arislan]

shorts (sparks) happen when i supply power to 1 and 3 or 2 and 4.  Nothing happens with power supplied to 2 and 3 or 1 and 4 or 4 and 3.

This explains a little about all their motors:
http://www.shinano.com/xampp/docs/Stepper%20Motor%20Operation%20&%20Theory.pdf

Do you see anything that could help me? I'd appreciate it.