You might look at damper motors. These are used to actuate smoke dampers in the ventilation systems of large buildings. The ones I've seen are 120 volt, and much to big, but have spring-loaded return, rotate through 90 degrees when power is applied, and use 1/2 the current when "holding" open. So if you could find a small 12-volt one it would be ideal for your application. I have no idea if sucby jgilmore - Mechanics
It does seem obvious that if you're doing primarily "one-offs" that print speed isn't really all that important. So if you're a developer, and wanting to prototype things, a slow print speed is fine, and doesn't really affect overall speed. There are two types of activity for which print speed is important that I can think of. If you're primarily printing out other peoples designs, or of you'reby jgilmore - Reprappers
The Arduino actually has internal pull-up resistors. You can activate them (and skip and external component) by attempting to write a "high" to the digital pin. Consult the data sheet for more info on that. Then the read value will no longer float, and you can use a simple switch connected to ground as your endstop. One warning: Hook up your switch so it's ACTIVE LOW. i.e. so it's connected to gby jgilmore - Controllers
Doesn't matter. I just checked and I didn't order any extra diodes. Unless LED's count. So it'll have to wait until I place another mouser order. Unless LED's count, but I'm to sleepy to check their data sheet right now. Time for bed. Actually, I knew about the back EMF problems with inductive loads from (your?) previous posts on the subject, so I knew exactly why you where saying that the diodeby jgilmore - Controllers
well, without unreasonably long build times, anyway. Assuming that we have solder (or field's metal, whatever) trace deposit tool working, we'd not be able to do fine-pitch SMD devices b/c the reprap can't make the required "channels" that narrow. Nor can it make the walls between the pins narrow enough. If we try, it gets exponentially slower as we decrease the extrusion width. Not only is thby jgilmore - Plastic Extruder Working Group
Thanks, nop! That's good info to have. Now, that should be "fixable" by sticking a diode into the screw terminals along with the wires to the load. The stripe goes towards the "minus" side, I think.by jgilmore - Controllers
That function is at the end of the process_string.pde file. IIRC. The parser is written more-or-less in C, it doesn't use many (if any) C++ features.by jgilmore - RepRap Host
I AM sorry for the ultra-blurry pictures - my cell phone camera is even worse than I'd thought. Heat sink it is! Give me a moment to try that... OK, now only PWM 2 has a lit LED. That makes more sense, the Diode and the Transistor are the same orientation as the others, so it's probably a soldering error. I'm guessing I fried the transistor. Just a guess, though. I see nothing obviously wrongby jgilmore - Controllers
I have the PWM driver v1.1 board, and when I plug in the high(er) voltage, every light on it lights up. Even for the PWM channel that isn't hooked up. It provides power too - I attached it to my nichrome and it did indeed get hot. I am running 24 volts instead of 12, so I switched out all the 560ohm LED resistors for 1Kohm resistors. That was on the advice of an EE, so I figure it's good. But Iby jgilmore - Controllers
Marius, Good idea! I tried that, but the naĆve approach doesn't work. The _init.pde needs to be included first. And there may be some other rules about the order that the .pde files need to be included in. And I'm not convinced that it wouldn't also be necessary to have the compiler spit out a list of #defines, and functions, for inclusion in a header file. Or maybe use "grep" for the #defines,by jgilmore - RepRap Host
If you want something a little more "developer friendly" you can skip the arduino IDE completely and use "make". There's a makefile included in the arduino distribution, but it doesn't work. Here's a version that does, but you also need the "main.cpp" file, which you will have to modify to include all your .pde's. This is what I've been using to compile the G-Code firmware. Now I don't have to uby jgilmore - RepRap Host
Ardunio version 12 seems to still have some difficulty maybe? There is a typedef defining a type called "word" which is later (your excerpt is to small to show where) is used as a array of type "char". Makes sense, as a word is a bunch of characters. But it doesn't work, because a type name (which typedef created) is a reserved word. There are three possible solutions which come to mind: 1. Dowby jgilmore - RepRap Host
There's a standard utility called "ps2pdf". It's a command line tool, comes with the standard install of ghostscript, which is installed by default on almost every Linux distribution because ghostscript is used for printing. If you have a pdf and want a .ps, this is what you want.by jgilmore - Controllers
Remember to factor in the cost of the motors, misc hardware, furnace cement, etc. as well. Motors are around $75 last I checked, and the furnace cement was $30 for a gallon at my local (Fort Collins, CO) store. Misc hardware such as rods, nuts, washers, screws etc are. MUCH more expensive (in the USA) if you try to do everything metric, I'd strongly suggest getting standard equivalents for everytby jgilmore - Controllers
I downloaded the older versions of avr-gcc and avr-libc from [ a href="http://blog.coldtobi.de/1_coldtobis_blog/archive/21_updating_avr-gcc_binutils_to_get_the_devices_update_now_also_includes_deb_files.html"] here as instructed, and got the error (among others) of as: unrecognized option `-mmcu=atmega168'. avr-gcc was calling /usr/bin/as instead of /usr/bin/avr-as. I fixed it by renaming as andby jgilmore - RepRap Host
Squintz, this is just exactly what I was looking for about a month ago. I wanted to make a big reducing gear for my wheat grinder, as the gearmotor I have doesn't have quite enough torque. To bad the whole thing's in storage now, along with my partly-functional repstrap, sadly. Definitely a resource to remember for later though. Thank you.by jgilmore - RepLab Working Group
Reading the past work that adrian did to make a simple robot that had RP'd circuits in it, they extruded the traces, press-fitted the chip, and soldered in the (non SMT) diodes. Seems clumsy to me - certainly better that having to mail off for a pre-printed board. Still doing all the soldering by hand. Hardly ideal for the "makes anything" printer! I've thought that the "final" version would beby jgilmore - General
An RS485 bus can be used for multiple devices. If you just leave that connected (via a flexible ribbon cable) you'd not have to worry about plugging and unplugging, which would both be easier and more reliable. I.E. Have all toolheads plugged in to the RS485 bus AND power (and probably a sync line) at all times. When the toolhead is inactive (i.e. the switch on the toolhead informs the toolheadby jgilmore - Controllers
IIRC, there's a command-line "reset the arduino" tool in enriques' skeinforge package. If there isn't, then I made one. Find it attached. Hrm.. Nevermind. In current form it resets the arduino, and then waits for the "ok" response when the bootloader has finished and the g-code firmware is waiting for commands. It is included in skeinforge, and even if you don't know python, it should be fairly eby jgilmore - Controllers
I've never heard of anybody using nylon. Possibly the melting point is too high. It's listed as 256C at and there's also mention of needing to dry it before melting it to prevent reactions with water. I think the temperature alone would prevent it extruding from a standard extruder, since the PTFE degrades around 260C. Sounds like it would be challenging to do. Go for it!by jgilmore - General
Forrest, you are not alone in that opinion. We have a serious problem. You ARE however, alone in your approach. From what I can see, it's a "commercial is fine as long as it's reasonably low-cost" approach. Which is fine as far as it goes, but doesn't work for me (I don't own a copy of windows) or for people with strictly-limited budgets. I imagine there are probably other reasons to reject the cby jgilmore - General
And a grey code absolute positioning sensor only needs one ring - but does need one sensor per bit of accuracy. As someone else pointed out in a post I'm not going to try to find, it's possible to design a ring such that each position is a unique set of sensor values and only one sensor changes between any two adjacent positions. So you only need one ring, but 8 or 10 pins. Bad idea unless you'rby jgilmore - Controllers
You don't need a lathe - The barrel is small enough that you can do everything you need to by loading it into a hand-held drill. I made several that way, worked great. Though I must admit I haven't squirted any plastic yet... It sounds much harder than it is. I didn't even need a drill-press.by jgilmore - General
I'm a little confused about this whole question. This isn't unusual for me, of course, but I'll ask anyway. Much simpler than a vise or etc. to hold the pipe is you just build the bottom part of the mcwire frame. With the pipes all screwed into one another and tightened in place, it's hard for them to move and you can sit on the other end of the frame if you need to. Who cares if the hole isn'tby jgilmore - Reprappers
I agree that the belts and gears aren't going to be reprapable. I don't see any way of avoiding generational loss of accuracy if we make our own belts and gears. Not without a much more complex manufacturing setup, anyway. But these'll be GREAT for all sorts of other projects! That floor sweeping robot will need some gears to drive it's brush and wheels. And though a complex articulated arm mighby jgilmore - Plastic Extruder Working Group
I've though about the acceleration thing. One solution is to replace "instant angle" corners, which require infinite acceleration, with arc codes. A circular arc gives us constant acceleration, but not constant acceleration on each axis. The g-code specification I read indicated two modes - constant feedrate mode (which may round corners to acheive a constant feedrate) or precise positioning (whby jgilmore - RepRap Host
I appoligize. They didn't work for what I tried to do. I'd post the g-code, but I'm not at home. I tried to write "Hello World!" and the e and o came out badly wrong. They where only a ~20mm across, and the problem was easily visible at that scale. Maybe there is a library issue? The noise issue is at least somewhat a limitation of the platform (no interrupts). The sqaushed diagonals may be a proby jgilmore - RepRap Host
As for linux/windows/mac, I think there is only one "simple to install" answer. That's a bootable CD/DVD that comes with everything. There have been massive problems with java libraries and versions of libraries on ALL three platforms. It's a nightmare to get working correctly. Too many people have failed, and needed expert platform-specific advice to get unstuck. It's not ideal, but I think recby jgilmore - General
Draw a circle. Make it about four or five inches across. Observe the drawing process. When it's done, examine the finished product. You'll observe the following things: 1. The drawing process is extremely shaky. There are significant pauses between line segments, which on my repstrap at least cause significant noise. It's fairly quiet till it gets to the arcs, and then it sounds like it's tryingby jgilmore - RepRap Host
James, That looks like some customer electronics, but fairly bog-standard opto endstops and the sangino board. Why did you go with custom electronics for some parts and not for others?by jgilmore - Mechanics