Stepper motor project?

Hi guys,

I wanted to buy a stepper motor and do some sort of a project. What other components do i need to come up with some sort of a project. I have the arduino Uno and want to potentially use the Kysan stepper motor..available for purchase from the arduino website.

Again I'm looking for a project that i could potentially do.

I know this isn't really project guidance but does anyone have any ideas?

Im kinda looking at trying to strengthen my knowledge with motors

You'll need some basic passive components, like resistors caps of various values, one additional IC motor, 14 seven segment displays (colour of your choosing, but green are the pretty ones), a DMC-12 (you can find used ones on ebay) and one flux capacitor.

Hi MrDropsy,
What about a robot, with stepper motors you can get precise movement, for each motor you will need a small driver module, like the ones that use the A4988 IC, etc. with these steppers are simple just 2 signals required STEP & DIR.

Or a Panograph, that is something to draw patterns with, two inter-connected arms both driven by a motor, the motors step at differnt speeds and/or direction. The end of the arm holds a pen/fine marker which draws on paper, etc..

Hope it helps.
Regards

Mel.

Start by doing some reading about stepper motors. They are very different from regular DC motors. Wikipedia has good stuff - but try to read more than that.

The simplest stepper motors to use are bipolar motors which can be controlled by a driver such as the A4988 that @Cactusface mentioned. The important specification for a stepper motor is the permitted current. The driver must be able to provide that current. It is usually best to drive a stepper with a high voltage. The A4988 can take up to 35 volts and it has a small potentiometer that you adjust to set the max current to suit your motor. The Pololu A4988 web page has a good wiring diagram and instructions about setting the current limit. If the A4988 can't supply the current for your motor you will need one of the more expensive "commercial" drivers - but the general principles will be the same.

This demo has some very simple code to illustrate how to control a stepper motor.

...R

for a simple project, I would put a laser pointer on a stand. then rotate it back and forth.
if you get two you can do a pan and tilt and then have more fun moving the pointer.

for a dead simple way to move the motor, use one transistor per lead (4 needed for a 6 wire motor.)

just a note about steppers, the only true accuracy is at full and half steps. the micro-stepping is more for speed and smooth operation. once you get one moving on the bench, you will see that full stepping is noisy. half and micro stepping really smooths out the vibration.

I did a stepper motor project, and it was published in Digital Machinist magazine. However, the gist of it is shown here, and the code is available to anyone from the DM site given on the webpage.

Hi guys,

Thanks for all your responses

I will be sure to read up about stepper motors

the one i want to get is this

http://store.arduino.cc/product/MK00742

Specifications:
Model number: 1124090
Holding Torque: 5.5Kg.cm
Rated Voltage: 4.2V
NO.of Phase: 2
Step Angle: 1.8° ± 5%
Resistance Per Phase: 2.8Ω± 10%
Inductance Per Phase: 4.8mH± 20%
Current Per Phase: 1.5A
Shaft: 5mm diameter w/ one flat
Insulation Class: Class B
Dielectric Strength: 100MOhm
Operation Temp Range: -20 ~ +40° C
Lead Wire: 22AWG / 750mm
4 pin 2.54mm connector

It says No. of phase is 2 - is that means its Bipolar?

I didnt realise i needed the driver module so ill look into those as well

where is the cheapest and most reliable place to get the A4988 as well those nice connectors

Hi,
That motor may have a low working voltage but 1.5Amps to drive it, you could up the voltage! The driver modules are widely available from retailers and cheap from China via eBay or Banggood, etc. also the dupont headers and jumper (Female) leads.

http://www.ebay.co.uk/itm/390924588268?_trksid=p2060778.m2749.l2648&ssPageName=STRK%3AMEBIDX%3AIT

http://www.ebay.co.uk/itm/361107960371?_trksid=p2060778.m2749.l2648&ssPageName=STRK%3AMEBIDX%3AIT

Sorry got to dash, be back later...

Regards

Mel.

MrDropsy:
the cheapest and most reliable

These don't necessarily go together.

I recommend you buy a genuine Pololu A4988 to start with. When you have one driver that you know works then you can buy cheap clones with the confidence that, if they don't work, you will KNOW it is the clone that is at fault and not your lack of knowledge.

And, as @Cactusface has said, drive the motor with a high voltage - the A4988 can take up to 35 volts. Just be sure to set the current limit to 1.5 amps.

...R

Thanks Robin2

Where can i purchase that genuine version - is that what you linked me before?

Can i set the current limit on the driver or do i do that using ohms law with a resistor

and how do i know that the motor is bipolar,

also i think id need a heat sink with 1.5 Amp

Google pololu a4988.

I don't know where you live but there are quite a few online suppliers of Pololu parts, as well as direct from them.

...R

Thanks robin , it is a bipolar driver

but im not sure what the kysan is and whether its compatible

also, how would i mount something on the shaft?

How can i prevent overheating

Sorry, I did what I regularly complain about and forgot to answer all your questions.

Going back to Reply #9
The Pololu web page explains how to set the current limit using the on-board potentiometer
That motor should work fine with the A4988
A heat sink would be a good idea but may not be essential. Be aware that the driver chip can get very hot - hot enough to burn your finger - while working normally.

Mounting to the shaft is another issue altogether. I guess a common way would be a wheel or gear with a boss with a grub-screw that is tightened to hold the boss onto the shaft. It will be important to get a boss that is the correct 5mm diameter for the shaft. I note that your motor has a flat on the shaft. The grub screw would screw down onto that. (My different brand motors don't have flats on the shaft).

...R

Thanks Robin, I guess ill have to find a wheel to buy from somewhere.

How can i attach a heatsink to the driver?

Not sure there is anything available for that

EDIT:

Also I'm looking at the motor drivers and there are so many devices with the same model number i don't really know which one i need, haha. One with the least amount of soldering would be nice.

MrDropsy:
How can i attach a heatsink to the driver?

I have never done that. I believe there is special paste but others may have better information.

...R

if you are looking to learn about steppers, make your own driver with transistors to get it to move. buying a driver will only teach you about connecting the parts.

by all means, do buy the driver, you WILL want to use it.

as for heat, do no use high voltage. the equation is simple.
if the motor cannot move the device fast enough, increase the voltage.
increased voltage will give the motor more power and generate more heat.
there are a lot of applications that allow you to use 3 volts. or 5 or 12.
if your device needs more speed, increase the voltage. the higher the voltage, the faster the device can charge the coils. the higher the voltage, the faster the coils are charged, and the hotter the motor gets when not moving. so, for many applications, the motor needs 3 volts, the power supply delivers 12 and the 9 volts is delivered as heat.

The motor’s output power is proportional to the power supply voltage divided by the square root of the motor inductance.
every time you double voltage, you deliver 4 times more heat. so, if you need 3 volts, and use 36, ........

steppers driven at high voltages will run too hot to touch with your hand. but it is rare hobbiests need that much power.
Robin2 mentioned that you can drive a that driver up to 35 volts, but did not mention that at 36V in might burn up. nor that the back emf of the motor will increase the voltage by about 20% in a rapid speed deceleration.

voltage should be based on the application.

now, some have a 500 hp car in the driveway and keep the pedal to the metal and adjust speed with the brakes, but I do not recommend that is a good design approach, certainly not for learning about using a stepper.

on the other hand, if you are running that metal cutting CNC mill, you need the power.

http://www.geckodrive.com/app-notes.html

The little heatsinks you can buy to put on PC graphics card ram chips are about the right size to put on the pololu driver chips and they come with a suitable adhesive on them - just peel off the backing paper.

Running a PC fan to blow over the heatsinks may help too. Most effective though is to use the little pots on the driver boards to turn the current down to the minimum needed for your application. Don't adjust them while you have power applied though.

Thanks dave - that is some really useful information for me, ill be sure to read through the link you sent me as well.

The one I'm getting has range between 8-35V. So since voltage is what matters here, do i adjust to current to say 1.5 A and just leave that while i adjust voltage how i need it?

Ill also look into using transistors to get the motor to move, I've got no idea how to do that, so that will be fun :slight_smile:

@wild bill

The little heatsinks you can buy to put on PC graphics card ram chips are about the right size to put on the pololu driver chips and they come with a suitable adhesive on them - just peel off the backing paper.

Where can i get them?

MrDropsy:
do i adjust to current to say 1.5 A and just leave that while i adjust voltage how i need it?

Set the current to match your motor. You don't need to adjust it if you change to a different voltage supply.

I'm not sure if you mean you have an adjustable-voltage power supply. I get the impression from other Threads that they may not work well with stepper motor controllers.

...R

Set the current to match your motor

Yea im pretty sure the allowed current is 1.5A

Well i have a power supply which i can control from 0 to like 30V. Would i be better off using say a 9V or 12V battery?