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Help for a Step Motor Drive

Thread starter #1
Hello All...

I am trying to make a Pan and Tilt Head for my Handy Cam Sony HDR-PJ240E. I have already made it one Unit. Its work Perfect at minimum zoom. My cam have 320X digital zoom. If I am set it with 230x OZ, the change is very high when it PAN. I have used DC motor and a small Gear System.

Now I deside to make another unit with Step Motor. I tried many circuit. I need one Step Motor Driver with Forward and Reverse with speed Controll, with a minimum components.

any suggession and a circuit with full schematic and code will help me.

Thanks in adavance.

Manoj Soorya
 

jpanhalt

Well-Known Member
Most Helpful Member
#3
I can't open rar files and couldn't tell whether any of your links include that. As for the schematic, it looks pretty conventional.
 

jpanhalt

Well-Known Member
Most Helpful Member
#6
There is plenty of code for driving stepper motors and several application notes from the various chip suppliers. I followed Microchip and ran a small motor. Basically, I just defined the states and called them as needed based on input from an encoder . The motor followed the encoder.

That might be applicable to your use, but I think you would be well served to work from the source code rather than try to depend on just the hex file.

John
 
Thread starter #7
Hi all,

I got another link......But how incres its speed ? this is the link : http://ccspicc.blogspot.in/2016/05/...-control-uln2003-l293d-circuit-ccs-pic-c.html

I have some doubts.

1. How to achive the maximum speed of the stepper motor ?
2. I just make a circuit what I want. But when I touch the motor, Its Stopped. I think stepper motors are so powerful. Is it?
3. I make it with 89C51 and ULN2003. as its minimum and maximum speed, its not run smooth. I feel some vibrations or like a jumping when its run. what the reason for that?

Thank so so much for your valuable time and Reply.

Manoj Soorya
 

MaxHeadRoom78

Well-Known Member
#10
is it possible to increase its speed?
The important thing with a stepper motor is to maintain the rated current, due to the current decrease as the inductive reactance increases with rpm, the power supply to the PWM or drive is increased considerably above the rated stepper voltage in order to maintain this current.
This now is normally done with a PWM style drive.
Max.
 
Thread starter #11
Thanks For your replys

I have some doubts.

1. How to achive the maximum speed of the stepper motor ?
2. I just make a circuit what I want. But when I touch the motor, Its Stopped. I think stepper motors are so powerful. Is it?
3. I make it with 89C51 and ULN2003. As its minimum and maximum speed, its not run smooth. I feel some vibrations or like a jumping when its run. what the reason for that?
Regards Manoj
 

jpanhalt

Well-Known Member
Most Helpful Member
#13
It looks like you are using a design for a unipolar motor. My work was with a bipolar motor. There are of course, similarities. To get smaller steps and less jerky movements, you can go to half-stepping, quarter-stepping to microstepping.

Of all the application notes I saved, this one one most valuable to me. It discusses the motor types as well as different ways to get smaller steps:
http://ww1.microchip.com/downloads/en/AppNotes/00907a.pdf

This was my second most used application note: http://ww1.microchip.com/downloads/en/AppNotes/00822a.pdf

The down side of microstepping is loss of torque and as Max pointed out, that can be compensated for to an extent.

John
 
Last edited:

atferrari

Well-Known Member
#14
Hola Manooj

I suggest you to google "Jones stepper motors". The tutorial, maybe a little long for your taste, will help you to get a pretty reasonable grasp of the matter.

To control a stepper, you could do it manually so it advances one step every time you bring one pin of a micro low. Do not worry; too-basic as it looks, is the best. After doing that test, I programmed a micro able to accelerate, going back a forth as required and of course, stop as well. I even used garden variety transistors.

I recall "seeing" you before. Kind of a Ritesh-like recollection.
 
Thread starter #15
Hello All

Thank you so much for your valuable time.

Thank you so much for the PDF referance, Jpanhalt. Thank you so much for the attention about in my post. Its most valuable for me too the PDF.

and

atferrari,
Great suggession. I cheack the "Jones stepper motors", Its pretty Good and I think its most suitable for me. I just get this circuit form Internet.

what is your oppenion?



Thank you so much all for your attenssion in my post.
 

jpanhalt

Well-Known Member
Most Helpful Member
#17
Have you chosen your stepper motors yet? The drives for the different types are different. Can you give us the model number?

If not, have you considered using inexpensive model servos? There have been big improvement not only in positioning accuracy but in power over the past 5 years. They are quite easy to drive and have the advantage of "absolute" positioning. That is, even if you move the shaft position when they are not powered, they will still seek the same position with the same input.

Stepper motors are not that way. You need to know or be able to find the shaft position when powering them up.
 
Thread starter #19
Proteus Simulation not work due to 74LS86- No model specification Problem. Need to try with real hardware. Will post here the result latter. may be after 2 or 3 hours latter.

Thank you all...Have a nice day.
 

jpanhalt

Well-Known Member
Most Helpful Member
#20
I was using "shaft" to mean the moving part inside the stator, i.e., what is called the rotor in the Microchip documents. I guess in theory, the rotor could have integral internal or external gear teeth and drive a gear rack or ring gear directly with a "shaft" per se. But, I suspect such designs are expensive. I did the google search you suggested and found some pan and tilt designs that are servo based -- in fact, this link was the first hit on my machine. The servo being used has a shaft and is a typical hobby servo.

https://www.robotshop.com/media/cat.../pan-tilt-kit-pixy-cmucam5-image-sensor_1.jpg

What would you call the clear area at the center of the motor in the illustration you posted?
upload_2018-1-29_16-19-49.png

John
 

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