Uln2003 Stepper motor controller help

[Enns]

Hello, my name is josh and im a 14 y/o electrical hobbyist. My current project is a XY plotter with two dvd rom trays. I am on a very low budget,(5 dollars) and i need a controller and schematic for it. i have looked into a uln2003 and i am going to buy some. My question is how do i hook up two stepper motors to two uln2003's and hopefully use a db25. Here is a picture of the machine. Thank you for your help.

 

[Fish4Fun]

Hey Josh Welcome to the forum!

First, I am glad to see someone your age interested in electronics and stages!

This is a typical 28BYJ-48//ULN2003 Stepper/Driver: http://www.ebay.com/itm/DC-5V-Stepp...941?pt=LH_DefaultDomain_0&hash=item3385233045 . It might be easier for you to simply order 2 steppers//dirvers from e-bay (the ones linked are slightly over your $5 budget @ $7.90 for 2 including shipping, but if you don't mind waiting you can likely get them from China for a bit less.)

CNC is a hobby of mine, and I have tinkered with all sorts of steppers, but I have never played with any of the old floppy steppers, so I don't know if they are typically unipolar or bipolar. I have seen some pretty amazing stages built using salvaged steppers, but a frequent problem with salvaged steppers is figuring out how to drive them properly.

If you want to investigate what others have done with salvaged PC Steppers here are a few links:

http://www.epanorama.net/circuits/diskstepper.html

http://bildr.org/2012/11/big-easy-driver-arduino/

http://forums.parallax.com/showthre...Stepper-Motor-with-high-speed-spin-up-circuit

Fish

 

[Enns]

That i could probably go over my budget for but i have one question, i dont have an aurduino and could i hook it up to a db25?

 

[CDRIVE]

That i could probably go over my budget for but i have one question, i dont have an aurduino and could i hook it up to a db25?

Hello Josh and welcome to EP.

Please clarify this statement. db25 is a model topography that describes the physical design of a "D" type connector. If you're asking if you could control the steppers via a computer in lieu of a PIC then you'd be asking if serial port control would work. This would be RS232 which describes data protocol standard, pin-out topography and electrical characteristics .

If this is the question then the answer is yes.

Chris

 

[Enns]

yes i mean the db 25 as in the serial connection. Another question, would this schematic work with my machine. Thank you

 

[CDRIVE]

As Alex Trebek used to say "Ooo sooorry"!. No that won't do at all. You must send serial data to a chip that can interpret it and convert the serial data to logic states to drive your ULN2003's. A Parallel Port will provide you with 8 separate outputs but your circuit exceeds this figure.

Chris

 

[Enns]

Could I do that whole process with a psoc 3 dev kit?

 

[CDRIVE]

I'm not familiar with it. Perhaps someone else is? I suspect you'd be well advised to investigate Picaxe uC's.

Chris

 

[Enns]

Yes I am familiar with the picaxe, could you possibly give me a way of hooking it up because if you think it is a good way to go I will buy some. Another question, will I need One picaxe for every unl2003

 

[Fish4Fun]

@ --> Chris
I am a bit confused why you think a parallel port OR a serial port will not work as a signal source? Both will in fact work quite nicely as long as you are using DOS or some other OS that allows direct control over the Ports. As a matter of fact, Mach3 (a Windows App), is (arguably) the most popular Controller App in CNC and is almost ALWAYS used in conjunction with a parallel port. Granted @ $180 per machine this software is not within the OP's budget; but DOS certainly is, and any DOS programming language (even BASIC) can easily control a ULN2003 via a printer port. Would I use a uController? Absolutely, but the OP is 36 years my Junior and on a tight budget.

Fish

 

[CDRIVE]

@ --> Chris
I am a bit confused why you think a parallel port OR a serial port will not work as a signal source?
Fish

I didn't exactly say that. My reply was based on Josh's schematic. With not having any clue of how many steppers he's driving, type of stepper or his exact stepper interface I based my reply solely on how many DB25 inputs he has. He has 12 data input lines. An LPT has only 8 data output pins. RS232 has only 1 TX data pin and 2 TX control pins. I have no experience with LPT but I can make RS232 dance for me with VB6.

Chris

 

[Enns]

Cool, I just bought a 5 axis breakout board on eBay that will controll the uln2003's. Do you think that will work? And if so could I possibly have a schematic

 

[Enns]

I just bought a 5 axis breakout board, could I controll the uln2003's with that?

 

[CDRIVE]

I just bought a 5 axis breakout board, could I controll the uln2003's with that?

Josh, please post the link to the controller.

Chris

 

[Enns]

http://item.mobileweb.ebay.ca/viewitem?sbk=1&nav=SEARCH&itemId=321133023129

 

[CDRIVE]

Josh, it's hard to beat the price, especially with shipping included. I would guess that a US manufacturer would have to charge $35.00 - $45.00 for that board. Don't be in a rush though because Ebay's "Direct From China" doesn't break any world speed records.

I read through the... uh.. "Specifications"???!! It reads like most of the stuff written in in China. I call it Chinglish! Let's hope that the instructions and product data included with the board is written in English and a heck of a lot more detailed than what's on that web page. I see no power handling components on the board so I'm going to assume that it's intended to control external drivers and that's one of my points. I didn't find anything in those "Specs" that even hint what the outputs will source or sink. We'll need to know this to properly select and interface the drivers.

Suggestion: Google this product to see if you can find users that have posted their experiences with it. I have no doubt that it will perform well. I'm only concerned with the documentation or possible lack of it.

Chris

 

[Enns]

So do you think it will drive a uln2003

 

[Fish4Fun]

LOL! Yes ENNS, that should certainly do it!

I hope you will keep this thread updated with your build progress. If you need help/suggestions relating to CNC that do not involve the electronics portion of your project, feel free to PM me and I will give you a link to a CNC forum where the topic might be more appropriate. As I said in my first post, I think it is fabulous to see young people motivated enough to undertake a project such as this.

I will tell you that it is extremely exciting to watch your build "move" for the first time!! But I should also WARN you, CNC has proven very addictive for me ;-) I have a small format (9in x 11in x 3in) CNC router I use for all sorts of things (routing/drilling PCBs being a cool one) and I have all of the parts for a larger format machine (28in x 40in x 8in) that I simply have not had the time to build. I have also designed a medium format CNC Plasma cutter that I have neither time to build nor the space to house, but hope to in the future My wife teases me, saying,"You are just like a kid except you have a credit card." LOL.

Anyway, Good Luck with your project!

Fish

 

[Fish4Fun]

I just did an e-bay search on stepper drivers, and I am amazed what is available at affordable prices! This is just 1 example:

http://www.ebay.com/itm/CNC-Router-...828?pt=LH_DefaultDomain_0&hash=item35cb27e02c

That is a single axis 12V-24V .5A to 3.5A (in 0.5A steps) stepper driver. For $11 delivered, it seems like a heck of a deal; however, perhaps more driver than you need for your current steppers.

If you don't mind sharing, you said in your OP you were building a "plotter"; what is the purpose of the plotter? How do you plan to control it? Are you familiar with CAD/CAM/Controllers? Have you given consideration to your rails? There is a TON of information available. Please feel free to ask questions.

Fish

 

[Enns]

That is so cool, I am so excited that you are helping me and could get me a schematic? And will the board improve the controls better than just a parelell port?