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Author Topic: Motorshield alternative?
woodpecker
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Post Motorshield alternative?
on: March 9, 2012, 14:13
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Hi everybody,

after soldering 2 adafruit shields im tired of soldering, especially as i burnt one because i didnt solder it the right way, i guess. is there any alternative shield which will be able to handle both steppers, or do i have to use 2 single shields? main aspect will be that it comes ready out of the box, because: see above. any advice for a stupid newbie is welcome!

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woodpecker
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Post Re: Motorshield alternative?
on: March 9, 2012, 14:44
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what do you think about this one, unless is doesnt support a servo?

http://www.komputer.de/zen/index.php?main_page=product_info&products_id=164&zenid=b9f2e31268b93358d06ad9eb7f63f684
sandy
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sandy
Post Re: Motorshield alternative?
on: March 9, 2012, 16:29
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You're right that most shields out there tend to only support one motor, but there are a couple which do two. They've seemed pretty expensive though. But that one you've linked to there looks great, exactly what we're looking for eh! I'm ordering a couple!

The adafruit motorshield doesn't actually do anything with the servo output except provide passthrough pins, so as long as you can access the pins on the board then it'll be ok.

The issue for me is which pins it uses for communication - if it keeps away from the SPI interface on pins 10, 11, 12 and 13 then this is pretty perfect (because I need the SPI pins for the SD card memory). The chips it uses are good ones, and serially controlled, so there's a good chance it does use different pins. Also capable of driving big motors too. Can you see any technical information about it (like what arduino pins it uses)?

To adapt it, I guess you'd need to do a little bit of chopping of the polargraph firmware to connect it up, but only the same kind of stuff as Lanthan did for his serial driver setup (http://www.polargraph.co.uk/forum/?mingleforumaction=viewtopic&t=21).

sn
woodpecker
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Post Re: Motorshield alternative?
on: March 9, 2012, 16:51
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Wow, thats cool, but i dont understand too much of the stuff thats discussed in the post you mention. first english isnt my mothertongue, second i dont know about programming also (nearly).i think i would need a guide in simple words.

datasheets are here: http://iteadstudio.com/store/images/produce/Shield/Shields/Dual_stepmotor_shield/Dual_step_motor_shield_DS.pdf

http://iteadstudio.com/store/images/produce/Shield/Shields/Dual_stepmotor_shield/Dual_step_motor_shield_SCH.pdf

and the pins you mention seem to be free................
SnyperBob
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Post Re: Motorshield alternative?
on: March 9, 2012, 18:52
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I just ordered my motor shield from eBay (China) and it came already assembled. It looks exactly like the Adafruit shield, and probably cost less. I got my shield in a kit with my UNO, sensors, etc...

Looks like just a shield is going for around $10 or $11, free shipping on eBay. I think that's a lot cheaper than Adafruit. I didn't realize you have to solder together the Adafruit one too, that sucks....especially for the price being so high!
SnyperBob
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Post Re: Motorshield alternative?
on: March 9, 2012, 18:53
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Please note, if you buy via eBay and it's coming from China, it took around three weeks for me to get it in the US. The money I saved however, made it worth it to me
woodpecker
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Post Re: Motorshield alternative?
on: March 9, 2012, 19:02
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thank you bob,

that sounds like a good alternative, as its assembled already its much better than the adafruit kit and very good priced (adafruit shield around 20Euro+5Euro shipping here in germany) . maybe i ll get me one, but first i will need another alternative, more easy to get, because im too impatient i guess to wait three weeks from now.

woodpecker
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Post Re: Motorshield alternative?
on: March 9, 2012, 19:51
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p.s.: can you provide a link to the shield, please?
sandy
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sandy
Post Re: Motorshield alternative?
on: March 9, 2012, 21:55
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I've had good and bad experiences with buying this kind of far-eastern enthusiast electronics stuff through ebay (for instance http://www.ebay.co.uk/itm/Motor-Drive-Shield-dual-L293D-Arduino-Duemilanove-Mega-2560-and-Arduino-UNO-/260956350570 - this is suitable for "Arudino" btw...). Can't beat the price (£9 vs £15) and it's hard to be sentimental when making that kind of saving, but on the other hand, I _do_ like to know that I'm support adafruit (the inventor of this shield and designer of the circuit, and a firm that has done more than just about any other to open up these treasures to laypeople like me) and my domestic hack suppliers by buying the real thing.

If you need your stuff pre-assembled, that's an added bonus. And it's slow, but that's not always such a problem.

Woodpecker, those pdfs are great, thanks for that, quite excited about this board. Looks like a great candidate for the next kits. Could do with a bit more power handling, but that's not a problem so far.

Cheers!
sn
woodpecker
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Post Re: Motorshield alternative?
on: March 10, 2012, 09:15
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Hi sandy,

im going to order one of those ITeadstudio motorshields and let you know. please be prepared to give me some assistance in setting up the firmware! THX!
sandy
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sandy
Post Re: Motorshield alternative?
on: March 10, 2012, 16:26
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No worries - I ordered a couple for myself, so will need to do it anyway. Good spot!

Looks like this is the right time to restructure the code to deal with multiple driver types eh.

sn
woodpecker
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Post Re: Motorshield alternative?
on: March 10, 2012, 16:39
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ok, so it was you who bought the other ones, i got the last one though. 🙂
sandy
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sandy
Post Re: Motorshield alternative?
on: March 10, 2012, 18:33
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Oops I almost stole them out from under you! I woulda sent you one 🙂
woodpecker
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Post Re: Motorshield alternative?
on: March 10, 2012, 22:47
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lets see who gets his first ;P
woodpecker
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Post Re: Motorshield alternative?
on: March 13, 2012, 12:55
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well, it arrived and looks gooood. i guess yours need a little more time to arrive. let me know when you have news regarding firmware.
sandy
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sandy
Post Re: Motorshield alternative?
on: March 13, 2012, 14:06
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Bah you beat me to it! Well my stuff usually ends up at the post office, so needs collecting, but I can make a start on the firmware changes - At least, I could if it wasn't Ironing Night tonight. Hooray...

That said, I think it'll be straightforward - just a matter of copying what lanthan did 🙂 Aha, though there is a new version of Accelstepper out, and that has a fix in it that might be significant for straight-line drawings (runSpeedToPosition), so I will try to get that fixed too.

sn
woodpecker
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Post Re: Motorshield alternative?
on: March 13, 2012, 15:01
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Dont hurry, ironing is serious stuff! I`ll try to get into this (the firmware,not ironing) somehow and see how much i can learn from this, but also waiting your results.

sandy
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sandy
Post Re: Motorshield alternative?
on: March 13, 2012, 23:53
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Hello, initial stab is at
http://code.google.com/p/polargraph/source/browse/embedded/branch/polargraph_server_serialstepper_itead/polargraph_server_serialstepper_itead.ino

Which is pretty much the same as lanthan's code I think, except it constructs the motors on pins 2, 3 and 6, 7. I guess the servo won't make much sense in it either.

// pin outs for the ITEAD motor driver shield
const byte motoraStepPin = 2;
const byte motoraDirPin = 3;
const byte motoraMicrostep1 = 4;
const byte motoraMicrostep2 = 5;

const byte motorbStepPin = 6;
const byte motorbDirPin = 7;
const byte motorbMicrostep1 = 8;
const byte motorbMicrostep2 = 9;

AccelStepper motora(1,motoraStepPin, motoraDirPin); 
AccelStepper motorb(1,motorbStepPin, motorbDirPin);
woodpecker
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Post Re: Motorshield alternative?
on: March 14, 2012, 08:43
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Great, ironing=inspiring!
woodpecker
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Post Re: Motorshield alternative?
on: March 14, 2012, 21:36
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hi, just tested it. the controller communicates with the stepper board and the machine is working as told, nearly. i will have to figure out why it still draws 90° flipped and one or two more issues.

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