Mechatronics > Motor Control

Arduino BED stepper Manual Control

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MarkN:
G'day. I am an older type Lecky, brought up on 6BM8's, Ward Leonard Control Systems, and was master Lecky on the ARK. But I have wasted the working part of my life in Sales and Marketing. So, you could say I know "stuff", or else "stuff all"
      I want to"manually" control, fwd/rev and speed, via a stepper, the X axis of a 2hp milling machine. Once up and running, I will then put a Stepper onto the Tailstock of my Lathe, then a Stepper onto the feed of my Bench Drill.
There will be the one controller, which will be transposed to whichever machine I need "feed"
This device in China, http://www.aliexpress.com/item/Power-Feed-Drill-mill-Machine-Power-table-Feed-Easy-control-auto-feeder-machine-free-shipping/1391609298.html   is precisely what I need, well 3 of them, but reckon, 3 steppers set up with 1 controller, will be a lot cheaper.
        Elabz, has a set up, with Arduino/BED, to do exactly what I want. But it isn't, behaving..!  :'(
According to the Cct,    http://elabz.com/manually-controlling-bipolar-stepper-motor-with-arduino-and-easydriver/#comment-27095  power from the BED, also provides power to Arduino. This is not happening, Arduino is not powering up.  Plug in the PC, via the USB port, 'n no problems.
BED power supply is 24 vdc, with 6 amps to play with.
I am using Arduino UNO R3 and Big Easy Driver v1.2, maybe wondering if there is a problem here.
    So, yes,  I need some help.   I am just not confident enough to grab 5vdc from the BED and slip it over to Arduino. ::)   
    Help, Please,
Mark Needham
September 1.  Got him sorted[/b]. Have connected up the 5v o/p from the Big Easy Driver to the Gnd/Vcc. No big Bangs. Just the port problem to get past now, and load the 'sketch'

MarkN:
Got him sortedNope, be buggered if I have.
Got Comms port 'n drivers in OK. Sketch finally checked and uploaded.
Power up, LED's light up 'n blink, and smiled. ( I'm sure)
tried him FWD, adjust speed. Nowt.
tried him Bwd, adjust speed. Nowt.
Switched him Off.  Poked, mumbled something 'n poked again, then said.  MMmmmmmmm.
Switched it back on Fwd, speed adjust and BINGO. The big IC on the Big Easy Driver, ( heatsink applied) worked like a piece of phosphorous, magnesium explodinium.
I'll be back when me new BED, arrives.
this post will now be moved to the Fireworks section.
Bugger.
If you are smiling and thinking of helping. Please do not bother. At least for a couple of days.

MarkN:
Reckon the Heatsink, I used for the chip, has "leant across" and shorted out a couple of the SMD's.  Still waiting for new driver. Have bought 10, normal Easy drivers, and will use TIP120 to up the "Extra Current"
https://www.youtube.com/watch?v=79Zk5tQRTEQ    for TIP120 details

ElectroNick:
Hi Mark,

Sorry it took me so long to chime in here. Did not have much time for the forums lately.

Here is my take on the situation: there is a way to make your own driver out of a whole bunch of MOSFET transistors (need two per an end of a bipolar stepper, and it has four ends, so 8 transistors), a heap of MOSFET drivers (IC that makes TTL control of a MOSFET easier) and a heatsink(s). So, it's a pretty involved device. And the issue of microstepping as well as current sensing and feedback would still have to be solved. You can use an Arduino as a stepper driver, but it will run out of available I/Os really quickly. With all proper feedback, you might not even get to control two steppers with one Arduino.

So, that's where the proper dedicated driver becomes so important. I would have to admit, for a powerful motor I would much prefer using a specialized IC rather than trying to use an Arduino as a driver, although this sounds like a fun project. Trying to bootstrap the Allegro chip used in Easy Driver to a  too powerful a motor won't probably do much good. I cannot say I know much about more powerful chips, sorry.

But as far as trying to get SOME rotation out of a freewheeling stepper, even a powerful one, using an Easy Driver, I think you should be able to use that schematic with the code at this site that you referred to without any modification with one caveat: the code here was written for the Allegro A3967 chip, whereas BED board has the newer Allegro A4988. I have not tried that one yet.

If you have ENABLE connected as per the schematics, try to disconnect it (it will make it always enabled and lead to excessive heating), and see if your motors at least twitches. The code assumes that each button press results in 160 microsteps (or 20 full steps if in 1/8th mode), so it should result in something like 18° angular movement of the rotor.  You cannot mis-wire the motor itself (it can only be wired to rotate in a wrong direction, easy to correct later), so don't worry about the motor, double-check the other important connections - Step and Direction

Anyhow, see if you can post more details, a picture perhaps, of your setup, I will try to be more helpful.

Cheers,
ElectroNick

MarkN:
Ta Nick. waiting for more "blow up fodder". Will post photos then, see if I can replay the last explosion. I do have a small stepper  So I'll prove concept first, and play further after that.
Cheers mate.
Mark Needham

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