[Windell Oskay]

Add on: assuming that etching goes well, the properties of the ninjaflex will likely be degraded on its surfaces. That may be why it isn’t recommended.

[Windell Oskay]

My experience with most polyurethanes is that very little can affect them in a serious way. Solvents that destroy plastics have very little effect. I don’t know Ninjaflex or other TPEs in this context, but my instinct would be that *if* you can get good adhesion to the copper, it will resist etching. It should be much, much less active in interacting with the acid than the copper is. However, what I would be primarily concerned about is whether and how you can remove it from the board after etching. If you can find a way– which might be as simple as melting it off — i would go ahead and try, with excellent ventillation. Even the acid fumes alone require that.

[Windell Oskay]

Be sure that you restart Inkscape after running the installer. If it still isn’t there, you probably have two copies of Inkscape on your computer. (Or more). Find and remove the extra copies.

[Windell Oskay]

Here is more specific information about the cases under which you may want to adjust the motor current:
http://wiki.evilmadscientist.com/WaterColorBot_Troubleshooting#Issues_arising_from_current_setpoint_on_EBB

[Windell Oskay]

> Could you possibly respond to the lights question and do you know anything about adjusting the current?

Unfortunately, the lights have never been a reliable indicator in cases like this. The current is factory pre-set (to a reasonable starting value), and should not be adjusted unless there is a specific reason to expect that it needs adjustment.

Not seeing the EBB in the device manager is very clear, as is the failure to contact it via RoboPaint RT or Inkscape.  Please contact our shop directly via e-mail (reply to your order confirmation) or use the contact form ( http://shop.evilmadscientist.com/contact ) to request an EBB exchange.  I’m very, very sorry for the hassle, and I’m glad that you were able to test with the other programs and with the other USB cable to pinpoint where the problem was.

[Windell Oskay]

Had we done this more recently, we might have approached it differently. In a sense, we did, with the digital version.  

I don’t exactly recall the original reasoning that we used for this construction, but one thing to note is that the CD4017 only outputs up to about 8 mA per pin. With the transistors, you can get it quite a bit brighter. It’s not particularly uniform in the intensity profile, but it was (to us at least) an improvement over not using the low-pass circuit.

[Windell Oskay]

Hi John,

I’m sorry to hear about the trouble.

The first thing to do is to figure out if the issue is specific to RoboPaint, or if it’s something else.  

– Do you get any kind of response at all within RoboPaint? 

– Are you able to get the WaterColorBot to respond from within RoboPaint RT or Inkscape?

If you aren’t seeing any response at all, you might check to see if the WaterColorBot shows up in the device manager. It should look something like “USB Serial (UBW-based) communications port (COM…)”   If not, you might try reinstalling RoboPaint — its installer also installs the Windows driver that allows you to connect to it.  You might try a different USB cable if you have one handy. You might try another port on your computer.  If you are connected through a USB hub, you might try connecting directly instead.

If the issue *is* RoboPaint specific, then things are a little worse. There have been a few cases that we’ve heard of where RoboPaint conflicts with something, and will not launch or connect on a given system. I’m afraid that we have thus far been able to  track down exactly what is causing it. If you can confirm that this is specific to RoboPaint, we would love to have your help tracking it down. (There is very little harder than tracking down problems that you can’t replicate.) There’s more discussion, here: https://github.com/evil-mad/robopaint/issues/127 

[Windell Oskay]

Interesting. First, make sure that you’ve overridden the auto-reset.  

Second, there have been quite a few reports of the mega2560 having issues with the Arduino as ISP process.

Here is a possible fix: https://code.google.com/p/mega-isp/issues/detail?id=30

[Windell Oskay]

You are not alone. I’ve actually been using 10.10 with (a slightly older version of) osxmenu since June. Installation is different, but (for the most part) everything works well.

The installer is not designed to work with the osxmenu version of Inkscape, which has a slightly different internal structure. (We will update the installer to support it when it becomes an official release.)  So, you’ll need to do a manual install.  Download the ZIP file from here: 

https://code.google.com/p/eggbotcode/downloads/detail?name=eggbot_2013_08_11_2.3.4.zip 

Unzip the folder, and place all of the contents in: 

Applications/Inkscape.app/Contents/Resources/share/inkscape/extensions/

Restart Inkscape, and you should be good to go.  You may get some extra “error” dialogs when trying to print, but I think that it’s only our error reporting that has an error– all of the machine control seems to be working well.

[Windell Oskay]

Hi Robert,

If you have saved the files as Inkscape SVG files, then you should not have any compatibility issues.  

There is a slightly newer Inkscape version, 0.48.5, but there are not any real “critical” reasons to update. If what you have is working, you can stay there as well.  

The current version of the Inkscape extensions for EggBot is 2.3.4, dated 8/11/2013.  

Now, as far as stopping the drawing mid-program, our directions have *never* stated that you could only do it by unplugging the unit. While that will halt a plot, it cannot be resumed when you do it that way, and it’s pretty rough on the hardware.  We do not recommend stopping a plot that way.  When you asked us this same question a couple of years ago, here was our reply, which is still what we would say today:

To stop a plot “gracefully” — at the end of the current or next line that it is drawing — press the “PRG” button on the EBB circuit board. 

  If you have stopped it this way, you can then use the “Resume” tab in Eggbot Control to resume your plot, or to instead cancel and return the pen to your initial position. There’s more information about that here:
http://wiki.evilmadscience.com/Eggbot_Control_v21#Resume

  I’d also like you to know that this information is up on our documentation site, as part of the “Making Your First Plot” information:
http://wiki.evilmadscience.com/Making_your_first_plot


 If you need to stop a plot immediately, you can also press the other button on the EBB (the “RST” or “reset” button), or unplug the Eggbot from power.  However if you do so, the position control will be lost, and it is not possible to resume a plot.

[Windell Oskay]

@crippledlord: Which version were you running before?

[Windell Oskay]

First, *thank you* for your kind words, comments, and suggestions.  Second– neat drawings and paintings. Love the Dorothy!

On the questions:

1. Multiple color washes.  You can have as many layers in an Inkscape document as you like, and you can rearrange the layers into any order that you like. Use Inkscape’s “Layers” window to add, remove, and re-order layers. You can also use the options in the Layers menu to do those and additional operations, such as “duplicate current layer” — one of my favorites.  

Please read our documentation about how to name layers; it is the leading integer that controls how the layer behaves, and you can give the layers arbitrary names, following the integer: 

http://wiki.evilmadscientist.com/Inkscape_and_WaterColorBot#Working_with_layers

2. Pause.  I don’t know of any obvious way to do this with the existing code base (other than manual layer changes). I don’t recall anyone asking about this before. You may be able to add a small delay by adding extra color changes, or forcing washing/re-inking cycles by drawing dots of (hopefully clear) water in unused places.

3. Force Paint Refresh. There is not currently a “good” way to do this. Paint refresh is done by distance painted only. One thing that some people have done is to set the refresh distance to be much longer (or off, entirely) and then to put each path on a separate layer. There are better ways that we can think of.

We’ve been trying to find a good framework for things like this for some time.  I’ve been keeping notes on it here, and you may want to participate in that discussion: https://github.com/evil-mad/wcb-ink/issues/24   

If you can help contribute to *clear* blueprints about how this kind of thing might be done, it might help to ease things along.

4. Lead-in/tail-off. Yes… I’d really love this one, but it’s not currently supported. Our code isn’t well structured for this at the moment, so hasn’t been straightforward. We do have an idea of what changes are needed, and so may be able to come back to it.

Requests:

1. Pause by layer. Should be possible. I’ve added it to the notes referenced above, on github: https://github.com/evil-mad/wcb-ink/issues/24

2. Blend. Paint mixing with watercolors is most readily done *on the paper*, and we’ve had great luck with painting down some water first, followed by one color, then another. A manual-dipping routine might be able to do what you’re asking, but more complex blending is problematic, especially from a UI perspective.

3. Water wash dish select by layer.  I can see what you’re suggesting, and it might be possible with some of those “manual layer” type commands.  In practice, we’ve had excellent luck mixing bright and dark colors, so long as we actually remember to do the full washing between layers, and change out the water manually if it gets too dirty. It might be more useful to be able to select which dish is used for re-wetting the brush, though.

4. Optional large sharpie adapter/arm. Making an adapter that fits both skinny brushes (like the Crayola) and fat markers like the “Fine” point Sharpie leads to poor performance at both extremes. We have made extra and custom brush holders for people who have wanted to purchase them. But… The current carriage design does not make it very easy to swap out the holder (a separate problem that we *are* actively working on), which is part of the reason that we haven’t made them generally available. 

For the short term, you may be able to find some fatter markers with skinny bodies. Alternately, you can modify the drawing to fill in the centers a bit. One way would be to duplicate everything and use Inkscape’s “Inset Path” command to make all the circles smaller. Another way would be to edit the StippleGen code to insert a second circle if the outer circle is above a certain size or (as I think we have done in the past) to draw small spirals instead of circles– they resize better.

5. Pre-saveable modes. This is likely not possible in the way that you’ve described, given the limitations of an Inkscape extension.  The Inkscape extension framework may change in the near future, though. 

6. Double-wide colors. We have evaluated quite a few watercolor sets for fit, and have recommendations about many.  Is that set on our list?  

http://wiki.evilmadscientist.com/Paint_Sets

[Windell Oskay]

It looks like using the “init” command multiple times may be the issue.  It allocates new memory each time that it is called, with malloc.  

That shouldn’t be an issue (and isn’t unless called in a loop!), but there doesn’t appear to be any process for freeing up the memory that is allocated.  You might be able to add a command to free up the memory: http://www.gnu.org/software/libc/manual/html_node/Freeing-after-Malloc.html

[Windell Oskay]

While the set of discrete transistors may occupy a volume thousands of times that of the 555 or 741 die, the difference in size is largely one of packaging. 

Here is an Xray through a TO-92 2N3904: https://www.flickr.com/photos/59935244@N03/5475873168

As you can see, the actual die is tiny– only about 0.5 mm (.020 inch) across, including the areas used for wire bonds. A modern 555 variant, the TLC555, lists its die size as 1.65 x 1.27 mm

(source: http://www.ti.com/lit/ds/symlink/tlc555-die.pdf ).  So, a naive estimate would be that one transistor has about 1/8 the area of a whole 555.  

Now, take a look at the die for that TLC555. There’s a photo here: http://www.bunniestudios.com/blog/?p=3542 . The big black circles are the wire bonds. And, there are several very large areas that look like intersecting combs. THOSE areas are the power transistors that handle the outputs.  Yes, some of them are 1/8 the size of the die, or close to it.   And, that’s on a modern chip — a “shrunk” die, based around super-efficient mosfets, not big and clunky bipolar transistors like the 2N3904.

So, a first inspection suggests that the actual area of the power transistors on the original chips is of the same order of magnitude as the area of our discrete transistors. It’s certainly not a difference measured in the hundreds or thousands of times. On the contrary: the sizes are quite comparable.

Getting back to your original question: Could you replace some of the transistors with more powerful types, and make a 555 or 741 with much higher current carrying capability? Absolutely!  Just watch the rest of the properties of the transistors, to make sure that you’re keeping with the same kind of device.

It is certainly possible to make more efficient devices than the 2N3904/6, through modern fabrication techniques and using larger areas.  

I don’t have any specific data about its die, but given that the ZTX968 is about 12 times the price of the 2N3906 (including packaging costs, which are fairly constant), it would make perfect sense economically if the die were 16X as large, 2 mm x 2mm, which would still fit nicely within the TO-92 package.

And yes, often smaller devices are preferred, because they have lower capacitance, and can be driven more quickly. 

As to our particular choices: the 2N3904 and 2N3096 are simple, inexpensive, and common “general purpose” transistors that work well for these kits in most respects.  There are a few places here or there that using a specific transistor with higher current or voltage characteristics would have been helpful, but we eventually decided (for both kits) that the simpler BOM was the better option.

[Windell Oskay]

Yes, exactly.  It looks better (to us, at least) with the low pass, but this does keep it simpler. :D

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