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Sounds like a great project, keep us all up to date on how you go!
The code is partly inspired by Darrin's code as I liked some of his constructors such as axis, motion controller, etc. However, the pin layouts and any devices (like EEPROMS, IO Expanders, etc.) would be fully configurable by the host software via custom gcode commands.
Yes, I too plan to make the pins configurable by the interface between the PC and the Netduino in my UI application. I just haven't got that far yet
You're pretty close. The software only cares about 1 limit switch per axis, which it uses for the home switch also when homing (automatically). You can have both maximum and minimum limit switches use 1 pin (wired in parallel) because it's impossible to over-travel in both directions at the same time. When a limit is hit, the software knows which one it is because of the direction it was travelling.
Here is my pin assignment list. Note that it's out-dated and I've since shuffled them around a bit, but this will give you the idea:
A0 - Jog X +/-
A1 - Jog Y +/-
A2 - Jog Z +/-
A3 - Speed override (%)
A4 - Step Resolution M0
A5 - Step Resolution M1
My software has most of them configured in one place, so it's very easy to change them to suit your own pin configurations.
I hope that helps.
Ha! This is good news. I was about to come to the forum and ask about using your software with the hobbycnc driver kits. My plan was to use the netduino to drive the parallel port. I'm assuming it is possible to store a gcode file on the SD card and then let my PC go to sleep while the netduino does the work.
Hey Mike,
Yes you should be able to use it to drive those boards. You won't be able to drive the parallel port per-se, but you can hit the step and direction pins directly.
My code does use the SD card to cache the motion commands (which are generated by the windows app when it parses the g-code). So yes, after the PC sends the whole g-code program, your PC can go offline.
The only issue with this that I still need to fix is that the machine pauses for about 200ms every 80 movements while the netduino reads the next chunk from the SD card. It isn't a very big deal, but I plan to solve this by reading the cached data in a second thread.
Darrin,
Finally desided to build a CNC. I wanted to know if the Arduino Motor Shield would be a good choice to drive the motors?
For stepper motors, take a look at the A4988 Stepper Motor Driver Carrier. It only takes two pins to step the motor and to set its direction. Take a look at the diagram on this web page to see how it is wired.
While not a shield, this is a bit more powerful and simplier to use.
I would agree with Tgiphil. The sheild could probably do it, but you would need 2 of them to drive the 3 axes.
The drivers he linked to are the ones I used and they work great. If you go with those, I have a few suggestions:
Use heat sinks and a fan on the chips. They can get hot after a while, and I fried one once. Since adding the heat sinks, they run nice and cool, and the smoke has stayed inside.
Also, be sure to follow the instructions for adjusting the current limiting output, again to prevent burning up your motors.
I will post a wiring schematic this weekend showing how I connected everything to the netduino. It seems that this could help a lot of people.
Enjoy your CNC adventure. Read a lot and take it slow and it will be very rewarding! I'm having a blast with mine (my wife calls it my mistress).
I guess I was looking at the shield because once you take in the cost of the A4988 and I figured there would be more parts involved it would be close to the same cost as the shield that is in a nice clean package. I have been thinking about the future and the possibility of a 4th axis so the extra drive on the 2nd shield would not be a total waste.
I will post a wiring schematic this weekend showing how I connected everything to the netduino. It seems that this could help a lot of people.
I guess I was looking at the shield because once you take in the cost of the A4988 and I figured there would be more parts involved it would be close to the same cost as the shield that is in a nice clean package. I have been thinking about the future and the possibility of a 4th axis so the extra drive on the 2nd shield would not be a total waste.
The wiring schematic would be great.
The A4988's are $10 per axis, whereas the shield is $15, so yes it's pretty close. There aren't any other extra parts and the drivers are pretty small (see my photo of the breadboard on the first page of this thread).
Also the drivers give you more options and have better stepper features such as current limiters. You can go with either but my recommendation would be the A4988, it's a real pleasure to work with.
Where are you finding them for $10 at pololu they are 12.95 before shipping.
Ah you could be right about that. I was going from memory.
ok, I did not see that pic I just saw the first one with all the parts, that looks simple enough.
Yeah that pic with all the parts was before the A4988's, when I first built my own driver. It worked good but lacked all of the features and simplicity of the A4988.
On a side note being this is by first machine I was looking at getting a Shapeoko. Am I missing out on the total experience by buying a kit?
My choice was to do everything from scratch, including the software and mechanical design because that was the challenge I was looking for. I don't necessarily recommend that approach unless you enjoy all of the problem solving and trial and error that comes with this.
If you just want a machine for the end results of having one, and you want it quickly, then a kit is probably your best way to go.
I really like the ridged design of the Shapeoko but they are currently showing sold out. Do you think a ridged design like this could be build from scratch for less than $190?
I'm building a shapeoko which uses the little NEMA 17 steppers. It doesn't look anything like the pictures on his site, because he doesn't have any up with the makerslide parts. Look at his videos though.
Regular motor controllers are hit and miss, and at worst, often don't let you have more than one or two axes controlled from your board.
Makerslide will likely have more kits in the next week or so. It's first-come, first-served.
Pete
Pete Brown - http://10rem.net (NETMF, C++, Windows, C64, and general geekery) Twitter: @pete_brown I work for Microsoft. Opinions expressed here are my own and do not necessarily reflect those of my employer,our partners or customers.
I actually found Shapeoko through makerslide. I am hoping to get started soon so hope he can get them in stock soon.
Have you gone to the Shapeoko site to see the full list of things you'll need to get? It's a lot more than the makerslide.
Also, the makerslide kit on the site gives you 8"x8" apx work area. You may want to get longer makerslide for the Y axis, but then you'd need to add a second motor and belt. If 8x8 is cool, then that little machine looks great.
I'm going to build it stock at first, but I suspect I'll want to make it larger rather quickly, so I'm planning on ordering some makerslide when it next comes in.
Actually, I see he just updated the shapeoko site with a brand new purchase page. Awesome
Pete Brown - http://10rem.net (NETMF, C++, Windows, C64, and general geekery) Twitter: @pete_brown I work for Microsoft. Opinions expressed here are my own and do not necessarily reflect those of my employer,our partners or customers.
Have you gone to the Shapeoko site to see the full list of things you'll need to get? It's a lot more than the makerslide.
Also, the makerslide kit on the site gives you 8"x8" apx work area. You may want to get longer makerslide for the Y axis, but then you'd need to add a second motor and belt. If 8x8 is cool, then that little machine looks great.
I'm going to build it stock at first, but I suspect I'll want to make it larger rather quickly, so I'm planning on ordering some makerslide when it next comes in.
Actually, I see he just updated the shapeoko site with a brand new purchase page. Awesome
Aww man, this stuff is beautiful! I've never seen this before.. where was this when I was doing my design?? I see a 2nd machine in my very near future!!
I really like the ridged design of the Shapeoko but they are currently showing sold out. Do you think a ridged design like this could be build from scratch for less than $190?
No, certainly not. That's a really good price for what appears to be a great design! All of the hard work has been done for you. Which is nice, but in my case, I wanted to do the hard work myself
Having said that, I'd definitely go for something like this. Although I'd probably opt to buy the stuff ala-cart so that I could customize and build a larger machine.
Actually, I see he just updated the shapeoko site with a brand new purchase page. Awesome
it is still not active
Right now we shut orders down until we get caught up on our current
backlog. I'm hoping that by the end of the weekend we'll have a better
idea of when orders will become available again. I know that's
probably not the answer you're looking for, but that's the best we can
do right now.
I took a look at the Shapeoko project (http://www.shapeoko.com), which I found very interesting.
I was looking to see what software a person required to go from an dxf or dwf file to sending gcode to the Netduino using this project.
I look at one particular piece of software today called CamBam but I am not sure if I am on the right track.
What are some other people looking at to generate the gcode to send to the Netduino?
Thanks, John
I took a look at the Shapeoko project (http://www.shapeoko.com), which I found very interesting.
I was looking to see what software a person required to go from an dxf or dwf file to sending gcode to the Netduino using this project.
I look at one particular piece of software today called CamBam but I am not sure if I am on the right track.
What are some other people looking at to generate the gcode to send to the Netduino?
Thanks, John
I am using CamBam to run my machine and I love it. It's very simple to use and also very powerful. As we speak, I am machining large wooden gears (for a clock) with toolpaths created by CamBam (Photos and video coming soon).
CamBam costs $150, but in my opinion it is well worth it for the amount of time it can save you, and the features it offers. It has a trial version which is fully featured but limits you to a number of sessions. I suggest trying it.
Darrin, Do you use any CAD software ahead of CamBam or can you do all of your design work within CamBam?
I guess I have always been under the impression that you have to use something like AutoCad to create your project, then import it into CamBam which converts the drawing into gCode. Once you have the gCode file you use a program such as Mach3 to instruct your CNC machine to cut the piece.
However, with the discovery of this forum I would no longer look into Mach3 (which I have not purchased or used) and instead use my Netduino as the device that drives my CNC machine. (I am very close to having my CNC machine running, I just need to learn to do some soldering to get my limit switches wired in).
So, to summarize above...Can I start a drawing in CamBam and skip the CAD step? If I can reduce my software side down to just $150 that would be a huge cost reduction from what I thought I would have.
Thanks for any comments that I recieve back, John