Stepper Motors not turning very quickly

[Flancrust]

so i bought a pair of these
http://www.ebay.co.uk/itm/5V-Stepper-Mo ... 2ebb662977

So I have it working with a couple of different versions of python code the one im using at the minute is the following
http://patrickcambria.com/downloads/stepper.py
heres a youtube video of the movement of this fellas motors
http://patrickcambria.com/downloads/stepper.py

now using the ones i bought from ebay i get a MUCH slower turn. it only turns about a third of the way round if that.

any ideas?? theres a few videos of people having smooth motion where it turns round several times.

[joan]

That stepper has an internal 1 to 64 gear chain. It also has 64 steps per (internal) revolution. To get one external revoloution you'll need 64*64 or 4096 steps. In practice I think 13 revs per minutes is good going.

[pygmy_giant]

I got one and they are slow - you get what you pay for.

[PS1981]

Yes this is unfortunately completely normal for this sort of motor. Unfortunately, they are only any good for trying out to see if you get the thing running at all. Check out videos in youtube - anyone using such a motor has no better results than you got.

My tip would be to search for something used in ebay (old printer motors for example) if you want to actually use them for something. I got a set of 3 there for about 20 quid not so long ago. You'll need a driver IC though to source the power for most bigger motors.

[pygmy_giant]

That little driver board you got with it however is fantastic as a ULN2003 breakout - you can connect it directly to the Pi and use it for loads of other things.

[PS1981]

theres a few videos of people having smooth motion where it turns round several times.

There is also a very similar looking 12V version which may give the better impression.

And by the way, steppers are not quick in general, they offer more control though compared to most other motor types.

[SN]

sssslowwwwww is good for my project - I don't want to mess with python, is it fairly trivial (and I should know this I know ) to wire this to a couple of GPIO pins and poke it from C code?

[joan]

I think it's easiest to drive it with 4 gpios. I suppose 2 might work if you split each signal and invert one of the resulting pair.

That particular motor has very little torque.

[Flancrust]

thanks for the responses. to be honest i picked them up as they were super cheap and the board with the ULN 2003 built in was a nice bonus.

It was kinda more a proof of concept before I spent any real money. I guess I have proved I can use them but need to consider something more pricey if i really want any results.

I have a couple of normal motors on their way along with an L293D to play with although I will have to built up the board itself. Will see how I get on with these before i make a decision about what motors I should use. I guess i could always get a more powerful set of motors and just attatch them to the boards.

[PS1981]

The ULN2003 IC's really wont hold up much. You´ll have them smoking in no time when you put bigger motors on them.

The L293D is a good choice (I use them for Steppers too). They get pretty hot though (it seems 120°C on the ground pins is not uncommon), and in a DIP package all you can do for a heatsink is etch a PCB with a large copper area around the ground pins.

[tenochtitlanuk]

I use usb-connected twin stepper motor driver boards called 'eibotboard' from Sparkfun.
You just send them a command from a serial terminal or Python. Much as I enjoy soldering up my own motor control boards ( since the SAA1027 & a BBC B days) it is much more sensible, and gets you productive much faster.

I use stepper motors from old printers- these are often 48 step. But the board 'microsteps' them, so they have a resolution of 48*16 steps per rev. And the command takes care of getting to the stepped position in a programmed length of time.

As a bonus you have RC servo commands on board. And digital I/O.

Stepper motors are seldom run very fast. Accuracy is their forte. But using a board like this at least removes the bottleneck of toggling GPIO pins and coding.
See some of my playing on http://www.diga.me.uk/360degreeCamera.html

JohnF

[HarryCB]

I use usb-connected twin stepper motor driver boards called 'eibotboard' from Sparkfun.
You just send them a command from a serial terminal or Python. Much as I enjoy soldering up my own motor control boards ( since the SAA1027 & a BBC B days) it is much more sensible, and gets you productive much faster.

I use stepper motors from old printers- these are often 48 step. But the board 'microsteps' them, so they have a resolution of 48*16 steps per rev. And the command takes care of getting to the stepped position in a programmed length of time.

As a bonus you have RC servo commands on board. And digital I/O.

Stepper motors are seldom run very fast. Accuracy is their forte. But using a board like this at least removes the bottleneck of toggling GPIO pins and coding.
See some of my playing on http://www.diga.me.uk/360degreeCamera.html

JohnF

Interesting little vase. Have you looked at Hugin for photo stitching all those things together - results are very good.