[Windell Oskay]

The presence or lack of a “blinking” program does not indicate whether or not the bootloader is working properly. It’s possible to have a bootloader present with blinking and it’s possible to have blinking on the “LED pin” without the bootloader.

The presence of the pattern does likely mean that the chip itself is working properly, but it is possible that the bootloader was removed (by someone else) or that something is interfering with the proper operation of the bootloader.  If you’d like to send it to us for diagnosis, we’d be willing to take a look and reprogram it if necessary.

[Windell Oskay]

The engraver attachment requires version 2.2.1 or newer of the Eggbot extensions for Inkscape, but does not require a firmware update. 

[We actually recommend sticking with the original EBB firmware version for the time being– that’s the version that we install, and that is for good reasons. A new version of the firmware (that is fully backwards compatible with the Inkscape driver) is near completion, but there may be minor issues here and there with the currently-posted newer firmware versions.]

Now, there are two separate issues that you’ve described.  

First, with the EBB that won’t enter bootloader mode: It may be the case that one of your buttons is not working correctly.  Try plotting with the Eggbot as you normally would (but perhaps without any pen). While it is drawing, try pressing the RST button to reboot the EBB.  It should lose communication, and give you an error message saying so. Then, while plotting again, try pressing the PRG button.  It should *pause* the plot, and give you a message saying that it has done so.

Second, for the engraver that isn’t working:

Make sure that you’ve enabled the engraver under the Options tab of EggBot Control, and make sure to test it (turning the pot from one side to the other) *while* you are plotting something with the EggBot.  Check your wiring, make sure that the metal part of the motor wire leads (not just the insulation) is making contact with the screw terminals.  Make sure that the servo cable is attached with the correct colors on both sides.  Check the assembly: Make sure that the diode and transistor orientations are correct. Be sure that when you added the LED, the long lead was going into the square hole. 

[Windell Oskay]

Can you please say exactly what is is that is “crashing” and by what mechanism? I wouldn’t expect either an Uno or a Peggy 2 to be able to “crash,” so I’m a bit confused.

Separately, the “PeggyWriter” is a useful example, but it *is* a user-contributed example that we do not have much experience using.  In a quick look, it appears that the example codes for PeggyWriter use a single instance of PeggyWriter, but multiple instances of PeggyScroller. You might consider trying that approach, to see if it works better.

[Windell Oskay]

The values on the example circuit were picked for being easy values to find, rather than for uniformity of the output signal. 

Plugging the values (100 k, 100 k, 1 uF) into a 555 calculator gives times of:

.14 seconds high

.07 seconds low

4.8 Hz overall frequency.

So, look carefully at your LED blinking, and see if it looks like that. If it doesn’t, first check your *external* circuit very carefully.  It’s pretty hard to get the 555 itself to oscillate repeatedly if there is a major error inside, so it’s more likely that the problem is outside.  Next, go through the 555 and check that resistor values are in the right places, and that the soldering is all secure.

[Windell Oskay]

Hi Glen,

Open up the “eggbot.py” file (in your Inkscape extensions) and find the line of code that says:

self.step_scaling_factor = 1

Change that 1 to a 0.5, and you should be good to go.

[Windell Oskay]

I can get that error if I comment out the #include line with the ds1307rtc library.  Is it possible that you don’t have that library installed? 

[Windell Oskay]

Great, glad to hear it!

[Windell Oskay]

Hi Dan,

The first thing that you should do is take a look at the circuit diagram, which is available in the datasheet. 

( See our documentation page, here: http://wiki.evilmadscientist.com/555 )

You will note that some of the transistors (Q5, Q8, Q18, Q19B, Q23) have pins connected together. This likely explains your “glitchy zeroes.”

Others are connected in more complicated ways, and you need to remember that the diode tester tests *everything* connected to the two points that you are measuring. In most cases, there is not just a single diode connecting any two given points.  

Most errors with the 555 are due to a misplaced or backwards component, or possibly a bad solder joint somewhere. It is also possible to damage a component while installing it, but isn’t very common.  (We generally recommend heating a solder joint for about one second, with a hotter iron.)

What I’d recommend to look further is to open up our “principles of operation” guide, and see if you can work through the circuit to see what is (and is not) working. Can you see a change in the output of the threshold comparator when you change its inputs?  Can you see the change in the output of the trigger comparator when you change its inputs? It sounds like you’ve got the right equipment and the inclination to work through it, and really see it works inside.  We’ve gone through this once– we intentionally let the magic smoke out of one (by putting enough voltage on– way outside of its limits), and were able to trace the damage all the way through to one of the transistors in the output stage.

You can use an electrolytic cap, just watch the polarity please.

[Windell Oskay]

I would definitely skip the resistors if possible– and it certainly doesn’t look to me like they’re needed in the application that you’re describing.

The note on page 12 is based upon how it is designed to work given power dissipation considerations in the IC package. It is not a statement about the most voltage that is allowed there.

But, let’s see where that voltage value comes from, and what it really means. At the device maximum current of 90 mA per channel, with 1 V between LED voltage and power supply voltage per channel, the total power dissipation is P = I*V = .09 A * 1 V = 90 mW per channel. With 16 channels, that’s 16 * 90 mW = 1.44 W.  That value is consistent with the maximum power dissipation for some of the smaller packages.  The ‘GN (RoHS DIP) package that we use actually allows up to 2 W, so there’s actually some additional safety headroom for us.

If you wanted to stay below that level of power dissipation with only 30 mA per channel (the limit of those RGB LEDs), you would need to have less than 3 V headroom (on average) between the LED voltage and the power rail.

Suppose that V_F is 1.8 V for the red LEDs and 3.6 V for green and blue, and that we have 6 red, 5 green, and 5 blue LEDs. Then with a 5 V power rail, the average drop is ((5 V – 3.6 V)*10 + (5 V – 1.8 V)*6)/16 = 2.075 V, and the total power dissipation is 16 * 2.075 V * 0.03 A = 966 mW.  That’s about 2/3 of the power dissipation in the example given on page 12, and well within the safe operating conditions of the device.   If you wanted to run a bit cooler yet, pick a slightly lower system voltage, maybe 4 V or 4.5 V, which will make it so that the MBI5026 will run cooler yet.

[Windell Oskay]

It’s a fine idea if you have an Arduino variant that is capable of a low-power sleep mode.  The most common varieties do not, because they have additional (relatively power hungry) circuitry that runs all the time.  Something like an Arduino Pro or Diavolino can shut down much further, though.

[Windell Oskay]

Hi Gonzo,

The Art Controller requires an incoming logic-low signal to trigger it.  The DS3231 does have an alarm output, and it looks to me as though its output is an “active low” type that would be appropriate for triggering the Art Controller (so long as you use a pull-up resistor, as described in the datasheet).

To power on an Arduino with the Art Controller, you can either use the same 9V DC power supply that you use to power the Art Controller, or a different one.  The simplest method would probably be to use the same power supply. Connect the + 9 V line both to the (+ side of the) Art Controller power supply input and to the “Common” port of its relay.  Connect the ground line both to the Arduino’s ground and to the (- side of the) Art Controller power supply input.  Add another wire from the “NO” port of the relay to the +9V input of the Arduino.

[Windell Oskay]

@BenLee3000: @firemankurt wrote “What is the formula to figure capacitor size when a 2v drop over 500milliseconds is desired on disconnect of a circuit where 4A is being drawn from an original 12v power source?”

If the initial voltage was 12 V at time t = 0, and it drops by 2 V in 500 ms, then V(t = 500 ms) = 12 V – 2 V = 10 V.

[Windell Oskay]

Great– glad to hear it.  And, thank you for your kind words about the WaterColorBot.  

[Windell Oskay]

I don’t see any fundamental reason why it shouldn’t work.  However, the SVG files that StippleGen produces are saved in “EggBot ready” format — that is, on a page of size 3200×800 pixels. That normally works out to 35.5 x 8.9 inches — larger than the WaterColorBot’s printable area. 

 If it seems like it’s trying to draw beyond the printable area, it probably is, and what you’ll need to do is to resize the SVG file to fit within the printable area.  The method to do this is different in RoboPaint and Inkscape.  In RoboPaint use the “fit content” button.  If you are using Inkscape, there is no automatic resize option that works well, but I’d suggest opening up a new WaterColorBot template and importing the SVG file to that document– then you can see how big the drawing will be, and resize it and drag it where you want it to print.

[Windell Oskay]

I can walk you through the process, using one of our standard example files. This egg was made starting with the “traditional1-layers.svg” example file, and making a few little modifications to it:
https://www.flickr.com/photos/oskay/13726009213

Step 1: Starting with the (white) egg, apply wax with the Electro-kistka, from the layer called “1-black.” This is the layer with the wide center “propeller” shapes. Since the wax is applied over bare white egg, the area under the wax will remain white when we’re done.

– A modification to the file: We moved four of the eight horizontal stripes from the layer “3-green” to the “1-black” layer to increase the amount of white in the drawing.

Step 2: Dye the egg yellow and dry the egg. Re-index the egg into the EggBot.

Step 3: Apply wax with the Electro-kistka, from the layer called “2-blue.” This is the set of zigzags at the top and bottom of the drawing. Since the wax is applied over yellow areas, the area under the wax will remain yellow when we’re done.

– A modification to the file: We doubled and flipped the zigzags on the top and bottom (Edit>Duplicate, Object>Flip Vertical) to make them into diamonds, not just zigzags.

Step 4: Dye the egg red and dry the egg. Re-index the egg into the EggBot.

Step 5: Apply wax with the Electro-kistka, from the layer called “3-green.” This is the set of straight lines at the top and bottom of the drawing. Since the wax is applied over red areas, the area under the wax will remain red when we’re done. (Remember that in step 1, we moved some of the lines from the original file from this layer to layer 1.)

Step 6: Dye the egg blue (where the photo was taken).

[Author]

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