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Topic: DC 5V 28YBJ-48 Stepper Motor Question (Read 2 times) previous topic - next topic

t0kmak

I bought a DC 5V 28YBJ-48 Stepper Motor for Arduino ((Works with Official Arduino Boards /2 PCS) (from here: http://dx.com/p/dc-5v-28ybj-48-stepper-motor-for-arduino-2-pcs-148819)

Here are the specs:
Diameter: 28mm; Voltage: 5V; Step Angle: 5.625 x 1/64; Reduction Ratio: 1/64; Can use uln2003 chip as driver

Now, i'm totally new at this, and from the test examples i could find this thing is really slow.
Is that what the 1/64 stands for?

And if that's true, than what's a good motor to drive a robot?

LarryD

#1
Jul 07, 2013, 03:28 am Last Edit: Jul 07, 2013, 03:30 am by LarryD Reason: 1
Look here:

http://arduino-info.wikispaces.com/SmallSteppers

Also, search for '28YBJ-48 on the forum.
The way you have it in your schematic isn't the same as how you have it wired up!

MarkT



Now, i'm totally new at this, and from the test examples i could find this thing is really slow.
Is that what the 1/64 stands for?

And if that's true, than what's a good motor to drive a robot?


That motor is for controlling air-vanes in car air-conditioning systems, it is neither fast,
efficient or powerful.

What sort of robot? How big/heavy/fast?  Is this for traction? - stepper motors are not efficient for traction, they are
for positional control.
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t0kmak

I'd like to build a robot that would wonder the room avoiding obstacles. Nothing fancy.

t0kmak

@LarryD Well that explain why it was cheap :) Sometimes being cheap gets the better of me, as i always pay twice.
Ok, so now that i know what it's for, what can i use for the robot?

jmknapp

If you want fine positioning they're pretty good (about 4000 half-steps per revolution, so < 0.1 degree), although there are a few degrees of play (backlash) on the shaft, so some accommodation would be needed to address that. The spec sheet gives a max 1000pps at no load, so that amounts to about 15rpm max.

MarkT


I'd like to build a robot that would wonder the room avoiding obstacles. Nothing fancy.


You need to work out some sort of size / weight as a starting point - everything follows from that - a tiny
micro robot could use the 28YBJ's, but would probably have Arduino Mini, 3 AAA's for batteries, and be
very "light duty".  I was possibly a little dismissive of them in retrospect.
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jmknapp

I've been experimenting with the 28BYJ-48 5V stepper to see what kind of application it might fit into--other than operating air conditioner louvers!

The torque is not very large. In a rough measurement I get about 250 g-cm. That's using an Arduino Uno to drive it, powered by USB, with the ULN2003 driver board that comes with the motor. The spec sheet says >300 g-cm, so it's in the ballpark.

The torque is unsurprisingly strongly dependent on the supply voltage to the driver board. With USB providing power, I see on a scope that the voltage drops from 5.0V to about 4.2V when the coils are energized, so it probably loses a little there. I tried driving it with 6.0V from another supply and the torque about doubled, to ~500 g-cm, but at 6V the motor gets pretty hot after about a minute or so, so that's probably not recommended, unless the use is very intermittent.

It's probably best to connect a separate regulated power supply to the driver board rather than using the Arduino-regulated +5V or USB.

terryking228

#8
Nov 30, 2013, 10:02 pm Last Edit: Dec 01, 2013, 07:10 am by terryking228 Reason: 1
Hi, I have updated the page on the ArduinoInfo.Info WIKI HERE: with more up to date information and two new Test Sketches for this stepper motor and driver board.

There is also an example of running two of these steppers, accelerating and decelerating in opposite directions, using AccelStepper library.
Regards, Terry King terry@yourduino.com  - Check great prices, devices and Arduino-related boards at http://YourDuino.com
HOW-TO: http://ArduinoInfo.Info

Bajdi

#9
Nov 30, 2013, 11:34 pm Last Edit: Nov 30, 2013, 11:38 pm by Bajdi Reason: 1
Those motors can be used for a robot, but it will be a slow robot...  I've done it :)

http://www.youtube.com/watch?v=aLozZ_RYIRE

I was using a 3S Lipo (+-12V), makes the motors run pretty hot. I haven't killed them yet. They are dirt cheap so can take the risk :)
I did need to write code to slowly ramp up the speed else I could not let them run that fast.  And I used 2 74HC595 shift registers to control the 4 ULN2003 boards. So I only needed 3 pins to control the 4 steppers  :D
www.bajdi.com

MarkT

Mmmm, slow, but I like the configuration with rotating motor mounts, very adaptable.
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