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Re: Preferences file - 17 years ago

Ha! Nevermind. Found it:

Re: Preferences file - 17 years ago

Just curious: Is there a page somewhere that documents each preference setting?

Arduino on OLPC - 17 years ago

Re: Getting Started - 17 years ago

In theory, you should be able to scale the Darwin design up or down by changing the lengths of the belts and rods. I don't think anyone's tried it though.

Re: RepRap Host / Arduino GCode - 17 years ago

So, is this a branch from the existing host software or does it support both Arduino and gen 1 electronics?

Re: RepRap Darwin CAD Model Files STL, Solidworks, max, 3ds? - 17 years ago

Assembly animations would be really handy. There were a couple times where I was reading the assembly instructions, looking at the drawings and really just not getting it. One part that stands out in my mind is the Z motor mounting. I think I had to do that three times before I got it right.

Re: Extruder Heat Profile - 17 years ago

I ran into a similar problem. If you watch the heater LED, you'll notice that it'll flicker normally for most of the heat profile, then it'll start turning off for short periods and the temperature will level off. As far as I can tell, it's some sort of interaction between the over-temperature protection and a lack of resolution at high temperatures. To get reliable high temperatures, you pretty

Re: Problems with Parts lister - 17 years ago

I took a first swipe at a BOM notes page and linked to it from the main Darwin page and the cartesian robot BOM page.

Re: Problems with Parts lister - 17 years ago

Yeah, I ran into the same problems last week. There's a thread over here: I've also detailed how I got around these things in my build journal. But, yeah, the documentation should probably be updated. I think I've got edit rights on the wiki, so I might be able to add some notes to the BOM page. Not sure what can be done about the parts lister, though.

Re: Reverse Engineering - 17 years ago

Ah, OK, so you can put bolts through these holes to keep the rods from slipping toward each other?

Re: unable to access google docs? - 17 years ago

...and, if neither of those work, here's a copy I generated:

Re: unable to access google docs? - 17 years ago

I don't have publishing privileges but I have been able to view the BOM here: If that doesn't work for you, here's an extract of the cartesian robot sheet converted to html:

Re: unable to access google docs? - 17 years ago

I saw that too. It looks like Google's changed their publishing parameters. Someone with publishing privileges on the BOM will need to update the wiki.

Action Figures - 17 years ago

I was showing my partially-completed RepRap to my 10-year-old son this weekend. I explained to him how it worked and what it could do. He thought about this for a bit and said, "So, you could make action figures with it?" I'd been so caught up in the industrial side of things that I hadn't really thought much about the leisure aspect. Custom toys and miniatures are an ideal application of RepRap

Anti-Anti-Backlash - 17 years ago

I'm in the midst of building a Darwin and one of the things I noticed is that the Z axis was very stiff. After playing around with this and that, I finally removed the spring and upper nut from the anti-backlash mechanism. As far as I can tell, the weight of the bed is enough to prevent backlash. I'll probably put the upper nut back in, just to give it a bit more support. My view on it is that I

Re: Reverse Engineering - 17 years ago

I'm part-way through building a Darwin but, as far as I can tell, the only important dimensions on the studding tie are the internal ones. The purpose of the part is to used the 2 trapped nuts to hold two rods a specific distance apart. One nut acts as a bearing against an M8 threaded rod. The other has an adjustment screw that pushes against an M8 smooth rod. The threaded rod rotates; the smooth

Re: Spring size? - 17 years ago

I ran into the same thing. Ended up using springs picked up at the hardware store. The ones I got were compression springs for screen doors: 2-1/8" long, 7/16" dia and .031" wire. Currently, though, I'm working without backlash springs. The weight of the bed seems to be sufficient to prevent backlash.

Cupric Sulfate and Ascorbic Acid - 17 years ago

I picked up some cupric sulfate and ascorbic acid recently. Cupric sulfate is either a blue crystal (pentahydrate) or a white powder (anhydrous). You can change one to the other by adding/removing water. I tried an experiment where I mixed anhydrous cupric sulfate, ascorbic acid and a bit of water. What I got was a brownish mush that was almost entirely nonconductive. I'm guessing I got cupro

Re: 8mm Rod From McMaster-Carr - 17 years ago

As it turns out, Home Depot had 3' lengths of 5/16" rod in stock. I bought 3, realized I needed more, went back and bought the remaining 4. Unfortunately, 3' lengths don't divide up nearly as well 1m lengths, so you end up using 16 rods instead of 9. I *think* that's right. I'll have to go over my receipts and make sure it was 7 that I bought from Home Depot.

Re: Parts Problems - 17 years ago

degroof Wrote: ------------------------------------------------------- > > For the motor couplings, I ended up using a > threaded rod coupling, bored out to the > appropriate diameters and held in place with a > couple grub screws. Here's a picture of one of these couplings in place.

PCB Business Card - 17 years ago

A printed circuit board the size and shape of a business card: Nice way to advertise your business and distribute a design. In this case, it's an ATmega168 breakout board but it could conceivably be any design that fits the form factor.

OpenMoko CAD Files - 17 years ago

Article here: Files here: Anyone familiar with IGES or Pro/E?

Re: Parts Problems - 17 years ago

I just went and looked at the McMaster site again. I got it wrong. The spider couplings are completely different from the Oldham couplings. It was the Oldhams that looked they would have a problem with shearing.

Re: Parts Problems - 17 years ago

//McMaster also sells a neat motor coupling that comes in parts so you can select two separate diameters// I saw those (or maybe it was an Oldham coupling) and wasn't sure if that would work, given the shearing force from the belt. I'd probably go with something like that if there were a support and bearing on the non-motor side of the coupling. I'm tempted to rig up some sort of support on eith

Re: Parts Problems - 17 years ago

Ah, OK, I think I've got it. In order to use the McMaster belts and pulleys, I need to: 1. Drill out the hubs to 5/16" (or 8mm). 2. Work out a way to couple the Y and Z motors. I'm leaning toward buying/making aluminum couplings. Both look like they'll be taking a lot of shear and torque stress. Closest I could find off-the-shelf was Mcmaster's part 2424K11. It's a 1/4" set screw coupling but i

Parts Problems - 17 years ago

Seems like nearly everything I ordered from Mcmaster-Carr is slightly off. The 8mm rod (88625K67) was 3' instead of 1m, which meant I had to buy about twice as many. Local hardware store had something that was close enough, so that wasn't too bad. The springs (9657K108) don't fit over the studding. I'll have to find a replacement. The toothed belts (1679K683) and pulleys (1375K39, 1375K57) do

Re: 8mm Rod From McMaster-Carr - 17 years ago

Just to clarify: I got the threaded rod from J&L Industrial Supply and it was the correct length. The smooth rod came from McMaster-Carr and was 3 feet long. I suppose I could see if the local hardware store has 5/16" rod. I can't imagine 0.0625mm will make much difference.

8mm Rod From McMaster-Carr - 17 years ago

Just noticed it's not in 1000mm lengths. It's 3 feet (914mm). That means you can't get, say, 500mm + 452mm from a single length. Looks like I'll need to order 3 more.

Re: Opto Endstop - 17 years ago

Speaking of which, do you have a donate button that I could put on my blog?

IR Thermometer Keychain - 17 years ago

Amazon has an IR thermometer keychain on sale for something like 40% off the regular price. I just ordered one. I plan on using it to calibrate thermistors and will definitely not be going around measuring the surface temperature of everything in sight. Honest.