Somewhere else on the forum someone else said (great citation there!) that the stepper manufactures often just use whatever wire they have on hand. Sometimes even changing wire colors in the MIDDLE OF A BATCH! Never mind keeping the wire colors the same for a model, they'll not even keep it the same for the same batch of the same model! This fun little factoid totally blew my mind. The upshot iby jgilmore - Stepper Motors, Servo Motors, DC Motors
Skeinforge, just like all the other slice/dice/print stuff including the official java host, expects a STL file. Most design software will have an option to export a STL file, it's a very common format. There exists a free plugin for STL export from google sketchup. Some free versions of full CAD packages omit that feature. Skeinforge doesn't have rotation support - the orientation that the STLby jgilmore - General
It's quite modular enough. The fact that I was able to change from step/dir to graycode without modifying the dda routine speaks volumes. Positively wonderful for something that is compressed as much as this is. I've been told that source code is like a gas - it will expand to fill any available space. I've found that source code is like a gas - when you try to fit a lot of it into a small spacby jgilmore - Firmware - experimental, borrowed, and future
I've downloaded your code and have started to make the modifications needed for it to drive my (still incomplete) machine. The main modification that my machine needs is my X,Y,Z axis use a found stepper controller that expects two coil polarity pins per stepper rather than step and direction, while the extruder driver is one of the pololu drivers, and needs step and direction. The found driversby jgilmore - Firmware - experimental, borrowed, and future
www.micromark.com They specialize in small tools, and you can buy a set of six or so (I forget exactly how many) bits of a specific size. I assume that's because they know that you know that you'll break some in the process of doing whatever it is you're doing. I bought two sets, one each of approx 0.5mm and 0.3mm bits. Haven't broken one yet, have made four tips. None of which have actually exby jgilmore - General
The Error is not in the firmware, it's a bug in the java host program. Specifically, the java host program tried to access an internal array (on the host computer, in the host computer's memory) and didn't access the array within bounds, tripping one of java's runtime accuracy checkers. Don't use java, and you'll avoid this type of problem. You'll have other problems instead. You can use skeinby jgilmore - Reprappers
I have my doubts about the pololu stepper drivers working well in that configuation. Any attempt to draw heat out through the mounting pins seems fishy to me. Especially when you consider that the current capacity of the stepper driver is limited by accumulated heat. The faster you draw heat out, the more amperage it can handle. For that reason, I'd assume you'll need a heatsink with fan on thby jgilmore - Controllers
If you knew precisely the curvature of your print surface, you could compensate in software by "warping" each layer of the print to match the underlying bed. This would allow raftless prints like nophead is doing, but without the tedious calibration and expensive super-flat aluminum. In other words, forget making the raft thicker, just make the layers of the part you're printing be of constantby jgilmore - General
The steps per millimeter (and steps per inch) is settable independently. You probably just need to recompile your firmware with the correct numbers. You did edit the .h file? Endstops are 1 per axis for zero positioning. It was originally designed for more, but last I heard there aren't enough pins on the processor to properly use them all.by jgilmore - Reprappers
VDX - I don't think I understand that. It seems that they must be using bearings with a larger ID than the shaft, and then offsetting a cocking them different ways to get the effect. Since the shaft is smooth, I'd think you'd lose some repeatability, same way as with a V belt, or other smooth belt drive system. Really cool effect though...by jgilmore - General
Looks good. Does it have locking, so only the "owner(s)" of a particular blog may post to it? I've been wanting something like that. Is there a forum extension too?by jgilmore - Administration, Announcements, Policy
I'd think they'd work fine with a geared extruder. We have to gear the extruder down anyway to get the required precision, and so it's effectively over-torqued. Some similar would work for the axis drives if you wanted the extra precision. It'd be at the expense of some speed, but the belt-driven design is too fast anyway, and we're not using anything close to the real speed it can go. So at theby jgilmore - General New Machines Topics
On the heated bed, a great deal of effort seems needed to get a perfectly flat surface. I'm getting the impression that this is because we're not printing a raft, and great flatness is needed to make sure the first layer of the object is of uniform thickness. Plate glass is cheap, available everywhere, and has a very flat surface. But it doesn't conduct heat well. Might it be worthwhile to coupby jgilmore - General
In my experience, polymorph doesn't need a releaser. Depending on the mold material and the temperature, of course. I've had success using it as it's own mold, without a releaser of any sort. I have a hand-cranked wheat grinder, and also a fine gearmotor thing from an "omega juicer". I heated some up, wrapped it around the locking bits of the appropriate parts, cut them off and stuck them in thby jgilmore - For Sale
Well, It may have been the low memory thing. I rebooted for the first time in months - I've been suspending my laptop instead of rebooting, but it glitched and turned off the display yesterday, so I had to reboot. And now the electronics forum has formatting back. Weird. Even weirder that it was JUST that one forum. For referance, I am running Debian lenny, firefox 3.0.6 w/ noscript 1.9.9.42, Cby jgilmore - Administration, Announcements, Policy
You can run the heater off of 24 volts as easily as 12. Just use a longer (twice as long, since it's twice the voltage) piece of nichrome wire, and you'll get the same amps drawn, and twice the heat production and power consumption. (Watts=Amps^2*Resistance, and Amps=Voltage/Resistance) This may even be better, as the nichrome's surface area will be larger, and it would run cooler? Needs researcby jgilmore - Controllers
No Cigar.by jgilmore - Administration, Announcements, Policy
The electronics forum has (for me at least) lost formatting. All the text is the same size and color, and it's all centered. Very odd, and much more difficult to read. Any idea how to fix this? I also have noticed that forums that I haven't been into never show new messages. If I go into them, I see all the new messages, even the ones that aren't really new. If I then hit "refresh" all messagesby jgilmore - Administration, Announcements, Policy
aka47 Wrote: ------------------------------------------------------- > To power your board from a 3v USB/Serial cable > open up the shell on the USB plug end and using a > spare conductor on the cable (disconect the one > that provides 3v) and tag it straight onto the 5v > feed on the USB plug connections where they join > the PCB. Sounds like a great idea, except that the cheaby jgilmore - Controllers
Using bit banging mode is a possibility. I didn't want to do that directly both because I have the decimilla, and my understanding of the bit bang mode is that it can easily take several hours to program the simple bootloader. To do the bit banging, you need four wires - two sends, a recieve, and ground. I think. Haven't read up enough on it, but from reading the specs from Atmel's datasheet, yby jgilmore - Controllers
Read boards.txt in the hardware directory of the arduino software. It includes the expected fuse byte settings. These can be written directly using avrdude in terminal mode. I used: avrdude -F -p m644p -b 19200 -c avrisp -P /dev/ttyUSB0 -e -t -u and then in the terminal: send 0xac 0xa4 0x00 0xfd send 0xac 0xa8 0x00 0xdc send 0xac 0xa0 0x00 0xff Which should set the extended, high, and low fuse bby jgilmore - Controllers
I'm still stuck in the "no way to power the board if I can communicate with it" thing caused by the simple lack of a USB hub. I visited radio shack, and they had hubs starting at $29 - a bit too pricey when I have one sitting at home somewhere. So I spent the evening dissecting my CA-42 el cheapo USB-TTL converter cable I got off ebay from some guy in Taiwan for $3 including shipping. First, Iby jgilmore - Controllers
OK, some successes. I wired a LED to the hearbeat, so I could tell for sure that the avrisp "sketch" was running, and with that tried to use avr in terminal mode to verify the fuses. Which, unfortunately, always read as "00" even when I used the "send" command to directly issue the spi command to write to them. For some reason, avrisp doesn't implement the fuse write commands. Anyway, I wasn'tby jgilmore - Controllers
3.5v motors are fine. Since the drive circuitry limits the max. current, the only result will be they'll move a little faster. They won't burn up, catch fire etc. Well, as long as you set the current control pot correctly. But this has to be done anyway, the steppers spec'd for the reprap aren't 12v anyway. There's more writeup on this elsewhere too.by jgilmore - Mechanics
I've got a basic breadboard atmel644PU, it seems to be OK. Now I'm trying to upload the bootloader and set the fuses, using a ICSP made from my old brain, a atmel168-20PU. No luck so far, just recording progress or lack thereof. Mostly so I can remember what I tried later. Programmed arduino with command: avrdude -F -p m168 -P /dev/ttyUSB0 -c stk500 -b 19200 -U flash:w:avrusb500.hex avrusb500.heby jgilmore - Controllers
K. I'll do that. I'll be running it via the laptop on a modified sine wave inverter. That's got a lot of noise, here's hoping it doesn't interfere... I'm also assuming that the vastly larger 100nF (~500x greater) caps I have won't do. Though I suppose they might for a (vastly) lower frequency.by jgilmore - Controllers
I just got some "shapelock" plastic and sqoushed it into aproximately the right shape. It doesn't need to be precise, after all. I admit, it doesn't work yet, but I'm sure it will just as soon as I get the electronics straightened out...by jgilmore - General
I forgot to order the caps, and mouser wants >$6 for shipping, so it'd be kind of silly to order 4 $0.08 parts.... I was wondering about the practicality of making them with a bit of wire... 22pF is hardly any capacitance at all, I'm wondering if I even really need it. The wire to the crystal itself as at least a couple pF of capacitance, I'd imagine. From what I understand, I don't need itby jgilmore - Controllers
Note the capital, it's the name of the system of measurement. Not that you need to care, since obviously you're not in the US.by jgilmore - Mechanics
I've always reversed the screw until it "clicks" down into the previously cut thread. This works fairly well, I've only occasionally had a problem with it even on plastic do-dads that I've taken apart dozens of times. You are correct that they will eventually fail, but even then you can design it so the threads can be simply drilled out, and replace the screw with a nut/bolt. You get a low startby jgilmore - Mechanics