This might not be workable without some sort of switch - leaving the mega's pins directly connected to the parallel port may not be the best idea. You could do it with a breakout board though - something that you'd plug the RAMPS shield into that has a DB25 connector on it, correctly connected to rows of pins that imitate the mega's. It'd be easier to go the other direction - get one of those fiby jgilmore - Controllers
The Z-axis problem sounds like a "current too low"/"trying to step to fast" thing. You might try adjusting the current pot on the Z-stepper, or giving it a very, very low feedrate to see if it responds correctly to that. I.E. G1 Z10 F1 Also, disable acceleration in the firmware. It assumes (incorrectly) that the speed is shared among the axies. This means that if you're doing: G1 X10 F600 G1 Zby jgilmore - Firmware - experimental, borrowed, and future
I find it odd that you're planing a multi-processor design. All four axises would have to be controlled from within the same microprocessor to get the timing of everything correct. Unless you have a "step now" signal line somewhere, and wouldn't that defeat the purpose? Commercially produced boards aren't that expensive, which allows you to use a small, cheap, processor with plenty of pins thatby jgilmore - Controllers
I believe that the ignore module is already loaded, it's just a matter of editing the site template. At least, that's the conclusion that I think was reached last time I mentioned it. That conclusion was based on the fact that unless you've clicked on a forum, unread messages don't show up. But once you've clicked on it, there is no way to restore the previous state. The topic came up becauseby jgilmore - Administration, Announcements, Policy
In a general sense, the host must wait for an OK, as that's what we're using to ensure that the host doesn't overrun the firmware's recieve buffer - dropping a command will cause a flawed print, and may cause a failed print. Regularly dropping commands would be guaranteed to cause a failed print. So flow control is needed. It seems like the firmwares should be required to ALWAYS send a respoby jgilmore - General
And maybe add the "ignore forum" feature?by jgilmore - Administration, Announcements, Policy
Cefiar: Clearing the cache worked. Thank you, that's been bugging me for weeks! The sub-forums and message lists that where showing up without CSS must have already been refreshed, as I don't see them anymore. It probably all happened when I was stuck in Arizona waiting for my car to be fixed, and forced to use crappy hotel/coffee shop connections.by jgilmore - Administration, Announcements, Policy
If the extruder is a stepper, you can reverse the direction by plugging it in backwards (make sure power is off) As for the others, it sounds like you're trying to adjust the size based on your results - this is a bad idea, as a small difference in the amount of plastic deposited can mean a difference in the measured size of printed objects. It's more reliable to calculate your steps/mm based oby jgilmore - Reprappers
I mean that for me there is no stylesheet. There is no color, everything is black-on-white, and there is no formatting, everything is the same font, no bold, italics, or size variations. One of the forums shows up that way too, and some of the threads. It's REALLY, REALLY, annoying. Makes it hard to see what's new, and hard to see what's part of which message.by jgilmore - Administration, Announcements, Policy
Is broken? It's been a couple days, is somebody working on this? I'd have expected an announcement if there was known problem, scheduled maintenance, or something of that ilk. Or maybe those with the power to work on it are using custom stylesheets and haven't seen it? I don't know. Maybe it's my browser?by jgilmore - Administration, Announcements, Policy
You could avoid the head crashing in software, and still improve resolution. 1. Do a constant-height scan, as now 2. Do a very close-up constant signal scan, using the data from the first scan to avoid running the head into the side of the lighter. 3. Since step 2 results in a partial scan (some areas can't be scanned) combine the data from both scans into the final result. Some areas will haveby jgilmore - 3D Scanners, Book Scanners, and Optics
I noticed that his granule feed head doesn't extrude evenly. It's got a consistently inconsistent feed, resulting in regular blobs. Obviously that's not a feature of every granule extruder, else the 3mm filament we buy would have that feature too. Perhaps the terminal end of his feed screw is too close to the orifice?by jgilmore - General
I think mounting the extruder with magnets would work fine. The mounting needs to be stiff enough to handle the abrupt direction changes without sliding around, so I do think the rare earth magnets would be needed. Try it and let me know how it goes? With pictures maybe?by jgilmore - General Mendel Topics
There must be some way of telling skeinforge to NOT do relative positioning on the "E" axis then. Or a way of telling EMC2 that the "A" axis (alone) is relative?by jgilmore - General
Impressive analysis nophead. I can see the low flow rate and extruding during moves. But the first layer height being incorrect? I've looked through those pictures and I can't even be sure if I'm looking at the bottom layer or the top. Which feature of which of those pictures gave you that information?by jgilmore - General
EMC2 has (I think) the best g-code visualization thing. Also simulates the build so you can visually *see* different feed rates etc. Note that "E" codes aren't supported. I've heard of people switching the extruder to the "A" axis, but that didn't work for me. Maybe delete them instead, as it's just visualization anyway? Or maybe there's a setting in skienforge to use absolute extruder axis positby jgilmore - General
Some of the firmware versions do a PWM value for the heater. They have one value for "heat it up" and another for "don't". Both are non-zero, I suppose on the theory that the lesser one will be low enough that the heater will still cool down, just not as fast as it would with a value of zero. Is it possible that the firmware isn't turning the heater off at all b/c the lower of those two valuesby jgilmore - Reprappers
Two things: A hose clamp will work (good suggestion, I'd forgotten that one even though I'm using similar on my machine), but so will baling wire (also called "tie wire" and sold by concrete suppliers) a roll of tie wire will cost about the same as 4 or 5 hose clamps, but will last MUCH longer. And will also take up less space, as you can simply cut off the excess. I was able to fit the baling wby jgilmore - Mechanics
Nichrome wire? You may want to use a vitreous enamel resistor instead. See Nophead's blog from which this was made. A smaller resistor works better according to nophead.by jgilmore - General
Also part of the point of running EMC2 (besides the awesome path prediction and speed/acceleration stuff) is the cool GL visualizations of the toolpath, and pre-built machine interface (jog buttons, G-code command line, etc) That couldn't (shouldn't) run on a stand-alone microprocessor. Even with the X86 requirement, I'm sure there exists a stand-alone microcomputer based on a pentium or somethiby jgilmore - General
OpenSCAD is a fairly new project, and therefore obviously doesn't have the sophistication that POVRAY has, as it's been around for years. Looking at OpenSCAD's .scad files, they look a great deal like POVRAY files. Is there a reason behind doing OpenSCAD instead of simply writing a STL exporter for POVRAY, or even doing as the candyfab project has and use a slicing utility to generate the sliceby jgilmore - 3D Design tools
I've been reading about EMC2 lately, and running it in simulation mode as well. I'm becoming convinced that the smart thing to do is to throw all our firmware efforts away, and rewrite the RT portions of EMC2 to run on a microprocessor instead. EMC2's understanding of acceleration and path following is MUCH, MUCH more sophisticated that what we have, or likely will have in the next 5 years unlesby jgilmore - General
It looks like either your X or Y axis is slipping, not your Z. The spider approach would work, allowing the shafts to be off-center. Your X and Y axis probably don't use the threaded rod though?by jgilmore - Mechanics
casainho Wrote: ------------------------------------------------------- > There are other problems like because code looks > to simple (maybe because the limitations of > Arduino program memory??), for example in the > implementation of G92 (set home) is not complete > for each axis, and so I get G92 E0 from Skeinforge > at end of each layer and that makes real problems > onby jgilmore - Firmware - experimental, borrowed, and future
I'm planning on making a stainless steel hot end and of course I'm just going to go to the local hardware store which doesn't really have much in the way of metric stuff. So I'm going to be drilling out my stainless bolt with a 1/8" drill bit. Do I need to get a 5/16" bolt or will 1/4" do? When I tap a 1/4-20 hole, I like to use a 13/64" drill bit, which implies that the wall will be 13/64"-1/8"by jgilmore - General
But it's so pretty! Or perhaps I should find a different gcode visualizer? There's no reason that my computer couldn't handle a nice 3D rotatable representation of at least this simple object. I'd expect other g-code visualizers to be aimed at subtractive machining, I wonder how well they'd work with our stuff? I'll download EMC2 and try that.by jgilmore - Skeinforge
That's REALLY irritating! One wrong click and I'm doomed forever. Stupid lazy forum administrator anyway. (nah, he's probably just distracted with too many other things to keep track of, reply to, and police, not to mention actual reprap stuff. I can totally understand low-priority items falling of the bottom of the list. Low priority to him doesn't mean low priority to me, of course. Uhm, speakby jgilmore - Administration, Announcements, Policy
Oh, I'd just been messing with support settings. So there's a little bit of extra plastic positioned oddly in this particular version. I was messing with skeinforge settings and regenerating the gcode to see what effect they all had, must have regenerated the gcode at least a dozen times. And yes, skeinlayer works fine. skieniso very consistently does not.by jgilmore - Skeinforge
I agree - using the extruder board to drive a stepper has always been a nasty hack. While you CAN run a low-Ohm stepper with it, you then are depending on the software to behave correctly at all times. I've always though that putting "don't blow up" in software is a generally bad idea. I'm doubly concerned about trying that kind of thing with an arduino, which has a ten second "bootloader" delay,by jgilmore - Reprappers
In the main forums list there are several which I never visit - reprap host, lasercutter, etc. Just things I personally have no interest in. Now, if I've never clicked on a forum it doesn't show the unread messages in red next to the forum's message and thread counts. That's nice, because I like to look through things and the red is eye-catching, and if I've never clicked on it, it doesn't showby jgilmore - Administration, Announcements, Policy