Author Topic: driverdudes no longer shipping  (Read 2555 times)

fsck

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driverdudes no longer shipping
« on: April 23, 2013, 05:29:43 PM »
Greetings everyone

I'm spoiling to build myself a sun tracker but it would seem driverdudes is no longer shipping their driver boards.
I'm having trouble finding a substitute driver board that will be compatible out of the box, i.e. without modifying the software.
Can I simply use a SN754410NE H-Bridge like here

I'm open to the idea of modding your, excellent by the way, software to fit my needs but I find it's better for me to start from a working whole.

Thanks in advance

    --  Fsck


Gabriel

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Re: driverdudes no longer shipping
« Reply #1 on: April 23, 2013, 07:19:23 PM »
Hi fsck,

I currently have the EasyDriver Stepper Motor Driver wired up in my circuit. There are of course, lots of other driver boards that would probably work too, including the one you linked.

I have attached a PDF showing how to wire it to the Sun Harvester Shield. If you are wiring them directly to the Arduino you should be able to figure out the pin assignments from the default program settings. I don't remember off hand exactly which order, but pins 2,3,4,5, and 6 are az step, az dir, alt step, alt dir, and enable.

How big of a sun tracker did you want to build? I guess that could also have a bearing on which driver boards you use.

Hope that helps,
Gabriel


fsck

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Re: driverdudes no longer shipping
« Reply #2 on: April 24, 2013, 07:40:35 AM »
Thanks for the clarification Gabriel

To clarify, I plan to start off small with a 50 watt PVC and these steppers.
I'll be using a bare AVR and forgoing the Sun Harvester Shield at the moment.

I'll try the H-bridge for my driver and let you know how that works.


fsck

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Re: driverdudes no longer shipping
« Reply #3 on: June 13, 2013, 06:46:46 AM »
Hello again cerebral forum.

I saw a really good deal on ebay for steppers and jumped on them.  The ebay page says these are rated for 1.7 amps and have a resistance of 1.5 Ohms.  I hooked one of these up to my arduino using a SN754410NE h-bridge with a 7805 feeding 5 volts to the motor and ran one of the stepper examples in the arduino IDE, this ran good for about 10 rotations and then stoped. After checking though everything I determined that the h-bridge had died, I replaced it with an identical chip (I purchased 10) assuming it was simply a dud but on the second go the same thing happened.

Looking over the data sheet I noticed that the SN754410NE is rated for 1 amp max, was I over-current?
I'm a bit unsure exactly what to do here, I ordered some L298N chips as they have a higher current rating.
Also, the ebay page says nothing about voltage, I assume that I can simply multiply their internal resistance by the current rating,
1.5 Ohm so 1.5 R x 1.7 I = 2.55 E.
Was 5 volts too much? 

Gabriel

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Re: driverdudes no longer shipping
« Reply #4 on: June 13, 2013, 08:32:18 AM »
Hi fsck,

Your stepper links seems to be messed up, but here is the fixed one if anyone is interested.
http://www.ebay.ca/itm/110991073907?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649

What circuit are you using? I see no reason why those stepper motors wouldn't work with the SN754410NE.

If you do have 5V going through the motor though and 1.5 ohms, then from

I = V/R
I = 5 / 1.5 = 2.15 Amps, which is too high for your chip.

The stepper motors I'm using (https://www.sparkfun.com/products/9238) have a winding resistance of 32.6 Ohms, considerably higher than what your stepper motor is listed as. I guess maybe yours are just used for a specific type of driver chip used for a specific application?

You might try measuring the resistance with an Ohm meter just to verify that the information on EBay is correct.



fsck

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Re: driverdudes no longer shipping
« Reply #5 on: June 13, 2013, 07:33:29 PM »
Hi again Gabriel,
Thanks for the quick and informative response.
 
As per your suggestion I check the windings and they all show 1.8 Ohm.
The circuit I used was straight from Tom Igor's page


It seams clear that I pushed too much amperage through the chip and fried it.
I though the stepper would only draw a large current if it had to push some weight, live and learn ;).
I'll try again now with an AA batterie as the power supplie.

It's interesting that these steppers have such different specs from yours, though they appear to be the same size and shape.  I think it might be like hi gear / low gear, low coil resistance means higher torque but lower top speed and a higher coil resistance is like a higher gear.  I'll look into it and get back to you.