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Topic: RepRap Stepper Motor Driver v1.1 (Read 1 time) previous topic - next topic

Hoeken

The open source RepRap project has recently switched to the Arduino platform as our microcontroller of choice.  In tandem with this, we designed a set of modular boards that allow us to accomplish our goal (making a self-replicating 3D printer.)  These boards follow a unix school of thought:  do one thing, and do one thing well.  Today, I present you with our Stepper Motor Driver.  Since it is modular, its capable of being used for any thing that requires a stepper motor driver.  Rockin!

This board will drive a bipolar stepper motor at up to 2A/coil in full or half stepping mode.  It has a very simple, industry standard interface:  step/direction/enable signals. every time you send a pulse on the step pin, it takes a step in the direction indicated by the direction pin.  the enable pin turns the entire board on or off.  it has a molex power connector making it easy to hook it up to a computer power supply, although you could easily put a .200" pitch screw terminal in there to use higher voltages.  it even has some cool indicator LEDs to let you know when its active.

The best thing:  its 100% open source with full Eagle files, etc. all up on SourceForge.

More information here!



MikMo

That looks like a good rock solid stepper driver.

Thanks for that

The_Bongmaster

B-dui in creation.

follower

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The best thing:  its 100% open source with full Eagle files

[hobbyhorse] I look forward to the day when "100% open source" is followed by something other than Eagle... :-(

The RepRap project is IMO great so I wonder if there are any plans to switch to using KiCad or gEDA or similar at any point in the future? [/hobbyhorse]

--Phil.

Oracle

This board does look great, but since you're doing it as open source, one wonders why your price for the board is so high compared to wha the the parts and small PCB are worth.

Are you hoping that a third party will develop and sell the hardware so the project can just focus on the design?

admin

Let's be honest KiCad, pcb, geda are really horrible in terms of user experience.... come on...let's be realistic about this.

A poor soul is designing a circuit, gives it to you for free, we should just be grateful.

Open source is about sharing , not about masochism.

eagle is free for you to use on 3 platforms... comes with lots of libraries that save you time you can spend with your girlfriend   and it provides a decent user experience to the designer. next thing they are going to come to your house and do your laundry :)


m





salsaman

#6
Jun 08, 2008, 06:42 am Last Edit: Jun 08, 2008, 06:47 am by salsaman Reason: 1
Oracle, your post begs the question: how are prices of $5 for the PCB and $28 for the kit "so high compared to what the the parts and small PCB are worth"?  I assume there's a markup to cover the time spent packaging kits and processing and shipping orders, and that doing the math would boil down to minimum wage or less for the dedicated RRRF folks...:)

Basically, I disagree-- the prices look reasonable to me.  Saving money by making the board and sourcing your own parts will take time, so it's sort of a matter of what you think your time's worth.

While the Rep Rap goal is still a long way off, this stepper motor controller is a great example of an open source subsystem-- hoping this paves the way for more practical open source machines than 3D printers: home appliances.
My Arduino blog: http://jmsarduino.blogspot.com
Comprehensive (?) Arduino-compatible board list: http://tinyurl.com/allarduinos

tvdbon

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Saving money by making the board and sourcing your own parts will take time, so it's sort of a matter of what you think your time's worth.


I've sourced all the parts for this and I am planning on making my own board (not that I think it is expensive, I just enjoy trying to make my own stuff), but has anybody had a chance to make a single sided pcb ?


Oracle

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Oracle, your post begs the question: how are prices of $5 for the PCB and $28 for the kit "so high compared to what the the parts and small PCB are worth"?  I assume there's a markup to cover the time spent packaging kits and processing and shipping orders, and that doing the math would boil down to minimum wage or less for the dedicated RRRF folks...:)


The 2 driver ICs are $10 combined (which I admit is a lot higher than I'd thought).  But the PCB should be under $2 (Golden Phoenix 155 square inch special for example), and a handful of support components.  It probably costs them $15 total.

At that price, maybe $28 is reasonable, as I said I thought the chips were a lot cheaper.  

Hoeken

Hey Guys!

Thanks for the support, I really appreciate it.  Let me quickly address 2 things:

1. we were originally using Kicad, but as others have pointed out, its not very easy to use and is a PITA.   it was actually getting in the way of doing Real Work, so we ditched it.  we periodically revisit it, and once it (or geda) gets to the point of being better then EAGLE, we'll definitely switch back!  of course if another alternative comes along, we'll switch to that as well (fritzing...?)  finally, EAGLE is free for most purposes unless you're using it to make money, in which case you can buy a $49 license (or go the grey route and use the gerber files we put up on sourceforge)

2. on the pricing, all the kits are made/sold by the RRRF which is a not-for-profit foundation.  while we do charge a markup on the stuff we sell, 100% of the proceeds go back into the foundation and fund the research on the next generation of the RepRap technology.  of course if you're still not satisfied, its 100% open source and you are more than welcome to either buy the parts yourself, or get the boards made yourself, or even make kits and sell them.  fine by us!  our only stipulation is that if you make changes, you give them back to the community =)

oops... i though it was going to be short ;)

Digger450

Thanks Zach, I think you guys are doing a great job!

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