2017. augusztus 26., szombat

Pen Plotter 4 - InkScape/KiCAD drawing toolchain

The first test of the plotter, this one:

was done with the following software toolchain:
I draw that spiral with InkScape, saved as DXF and converted with the DXF2GCODE software from sf.net:
Tried to use a few gcode sender, but finally kept using the Rasberry PI/Ubuntu/Octoprint set. As I'm quite familiar with it from my 3D Printing past.
The toolhain above has some drawbacks:

  • I wasn't able to produce correct scaling. I don't know it is just my inability or problem of the software used.
  • The DXF2GCODE is more likely a basic CAM software and not just a plug and play conversion solution. The plotter needs much simpler gcode than a CNC Router, and the functionality of working with tools, pockets unnecessary at this point.
  • There is a drawn line between the home point and the start of the spiral what isn't in the original drawing. It is not caused by the toolchain. I'll will come back to this issue later

At this point I was thinking a bit differently. The DXF is a mechanical CAD format, so not really designed for pen plotters, but the HPGL definitely the language of the HP pen plotters.
I searched for a program what is able to convert HPGL to G code. I found a few converters. None of them was fit into my needs. Most of them was not able to convert the HPGL AA arcs to G2, G3 gcodes. This conversion needs some trigonometrical knowledge so it looked hard to achieve for some programmers. After a few trials I gave up to use something I found on the net.
So I wrote one. It is in the github repository of the plotter:
It still has some problems like incomplete error handling and lack of path optimization, but does it's job.
Now let see, how the toolchain works
Here is the original drawing:

First all of the object in the drawing must be converted to path, otherwise it will not represented in the HPGL output:

When it's done, you can save it as HPGL:

Now the bit tricky part coming:
The InkScape HPGL save dialog default parameters are mainly setup for cutting and not drawing plotters. Therefore most of them need to be changed according to the following:


Now you have to convert it to G code.
I used two different settings. The reason is the G code of my plotter use M280 P0 S50 command to lift the pen and M280 P0 S0 to put it down.
The usual CNC routers use G1 command to move the Z axis. The widely used G code simulator CAMotics Doesn't understand my pen up and down commands, so for the simulation I changed them to G1 Z5 F50 and G1 Z-2 F50 respectively:

And here is the result in the simulator:

As it looked good, I made the conversion for the plotter:

As you can see, the PenUp and PenDown parameters are missing here. The reason of this that it was setup in the application config file.
After this uploaded it to the Octoprint and sent out to the plotter. The result is disaster. It drawn a 2cm dashed line from the home point towards the starting point of the drawing, then drawn the whole drawing in the air (pen lifted).
I known what is the problem, from the first moment. It is the same problem what I mentioned at the beggining of this post (line from the home point to the beggining of the spiral). The G code commands are not executed in order.
I know about the Marlin firmware that it queue the commands and some commands are executed in order and some out of order. I was reading the source code of the Marlin for a few hours to find, how to change this behaviour Unsuccessfully. I gave up at this point and asked in the Marlin forum.
The answer was much more easier than I ment. Adding an M400 command (wait for finish of the previous commands) before an out of order command solve the issue. I wasn't even need code change for this as my pen hadling commands are represented in the configuration file.
The only trick here that the handling of the multiline string in the .Net config file. So the parameters look like this now:
M280 P0 S0

And finally the result:

The converter I wrote also understand the HPGL output of KiCAD. It can be used for drawing and not PCB milling. This will come later.

2017. augusztus 14., hétfő

Graylog, Elasticsearch, Maximum number of fields, graylog_deflector

Just because I'm not a Linux guy
A few days ago, I setup our shiny new Graylog server.
I successfully added something like 10+ windows servers to collect the event log entries from.
As the second part of the task I wanted to add linux servers also.
I added the first one, it looks like the collector running and the messages are arriving, but no message shown on the web console. Weird.
Digging a bit deeper I found thousands of this message in the indexer fail:
{"type":"illegal_argument_exception","reason":"Limit of total fields [1000] in index [graylog_0] has been exceeded"}
This means we exceeded the maximum field number (I think due to the event types in the Windows).
I read through some forum posts about it. Tried to change the settings in the elasticsearch.yml file.
It didn't help. The result of my actions was a inoperable elasticsearch.
Finally I deleted the whole thing (elasticsearch) together with the indexes, and reinstalled it.
The result:
A working elasticsearch instance. The 1000 field limit kept, and in addition I got a new error. It said something like this: The graylog_deflector is an index and not an alias.
Googling around, I found the problem, but not the solution. Then I was start to think instead of googling. What I've learned:

  1.  From one of the log files I learned, that the elasticsearch configuration isn't done through the config file but through the web API with JSON objects.
  2. curl is your friend
  3. The Graylog creates a graylog_deflector index when it can't find the graylog_deflector alias. What it unable to use. You can't do anything with it from the Graylog, so you screwed.

The solution based above:

  1. In the Graylog web UI go to the System/Indices>Indices. Select the Default index set
  2. In the Maintanance select the Rotate active write index. It will create a graylog_0 index (but it will not work)
  3. Go to the console and stop the graylog:
    sudo service graylog-server stop
  4. Handle the 1000 field problem:
    curl -XPUT 'http://localhost:9200/_all/_settings?preserve_existing=true' -d '{
      "index.mapping.total_fields.limit" : "5000"
  5. Stop the graylog_deflector index:
    curl -XPOST 'localhost:9200/graylog_deflector/_close?pretty'
  6. Delete the graylog_deflector index:
    curl -XDELETE 'localhost:9200/graylog_deflector?pretty'
  7. Add the graylog_deflector as alias to the newly created graylog_0 index:
    curl -XPOST 'localhost:9200/_aliases?pretty' -H 'Content-Type: application/json' -d'
        "actions" : [
            { "add" : { "index" : "graylog_0", "alias" : "graylog_deflector" } }
  8. Restart graylog:
    sudo service graylog-server start
  9. Now the graylog starts the correct reindexing process it can even take days to finish, but you can see your collected messages in the meantime.

2017. július 31., hétfő

Pen Plotter 3. - Working

It is finally working.
Built the whole thing, assembled, then redesigned most of the pen holder.
The problem was the following:
  • The SG90 microservo I intended to use was not strong enough
  • The line I wanted to use to pull up the Z carriage was a bad design decision
  • The arduino was not able to provide enough current to the stalled microservo, so it rebooted when the pen pulled up.

In the new design:

  • The SG90 replaced with a more powerful MG995
  • The servo moving the carriage directly
  • Added a 6V regulator for the servo, what gets its power from the beefy 12V PSU and not the arduino.

The electronics on the head still messy as I don't designed a proper PCB yet (but it will only happen when I finish the milling and the laser engraving head design):

And finally here is the first video of the working unit:

2017. július 27., csütörtök

Pen Plotter 2. - Measuring Proxxon

I've a Proxxon Micromot drill. I'm planning to attach it to the plotter as replacement to the pen, to be able to do some light cuts.
For this I don't want to use it's original power supply unit. As the speed control is located in the power supply I wanted to know it's properties:

  • How the motor driven? Pure PWM or filtered to DC?
  • What is the PWM frequency?

To measure this without disassembling, not looked like an easy task. The reason is that Proxxon uses a proprietary connector, what is not available on the market. So I measured the diameter of the pins and looks like with two 2.3mm drill bit I made it:

The measurements:
Without load:

At minimum speed:

At maximum speed:

It is a bit noisy to my taste and figured out that it runs at 100Hz and not really filtered.
Based on this I can design the new electronics into the plotter.

2017. július 5., szerda

Pen Plotter 1.

I'm not documented this project deeply, step-by-step. Now I'm just writing where am I today with the build. Mainly pictures.
More than three month ago I had a conversation with my son. He told me that he want to build a "drawing machine" essentially a pen plotter together with me. I started to design one. After a few conversation he told me that he wanted to build it from Lego.
I was already too deep in the designing already, so I didn't want to stop. In addition I was planning to add exchangeable head to be able to use it as a light router and a laser cutter/engraver.
I think the design mainly finished:

I left out a few things from the design, like drag chain, screws, spacers, timing belts.
During the design process I already printed some of the parts:

As you can see, there are some assembled parts also on the picture, like the Y axis drive (round white thing in the center) and Z axis carriage (the green thing).
How the Y axis timing belt mount into the holder:

Lots of holes, the base plate:

X axis assembled:


2017. május 27., szombat

StepTest 1.

During the Cyclone mechanical build I hate when I have to wind various axes by hand from one end to the other. I was thinking. What if I build a simple circuit for the stepper motors to do this for me. No MCUs, just a stepper driver, a variable oscillator with a speed control potentiometer, a direction control switch, and the necessary power supply.
I wanted to keep it as simple as possible, so I just picked up two schematics from the net as base.
The DRV8825 stepper module minimal config from pololu:

And a 50% duty 555 config:

I used 680nF in the place of the C1 and a 1K resistor in series with a 10K potentiometer in the place of R2. Here are the result.


This allows me to change the frequency between 74 and 704Hz.

In addition to the two circuits above I added a simple 78l05 regulator, so the whole circuit runs from a single 12V supply.

Here is the build on breadboard:

During the test I realized, that the motor is quite noisy. So I think to use the microstepping and in parallel increase the frequency by reducing the value of the C1.
Next: proper build.

2017. május 26., péntek

Cyclone PCB Factory 5.

Oh, noooo.
I just tried to attach my Dremel to the Cyclone:

This doesn't work.
Just found out that I've a Dremel 300 and the Z axis is designed for the Dremel 3000.
There are no ready design available for the Dremel 300. Shit.
I've a few options:
Design a Z axis for my Proxxon.
Buy something from eBay/Aliexpress (775 DC motor, CNC spindle), they have ready Z axis design.
Buy a Dremel 3000.
After a half day thinking, evaluating the options, decided to buy a Dremel 3000. It needs the least effort now. I was able to find one for ~$40.
I ordered it in the morning. It landed in the FoxPost's box on the same evening (It was fast):

2017. május 25., csütörtök

Cyclone PCB Factory 4.

Started to correct the things from the previous post. Went to two local shops (had no more time), to find M3 grub screws for the steppers. No success.
What if I try to make a few at home.
Here is the setup:

And the result:

I think, not bad for the first try.

2017. május 24., szerda

3D Printed glass identifier

I've three kids. Usually they leave the drinking glasses around the house and after a few minutes nobody remember who owns a practicular glass.
I wanted to end this. So I designed a plastic  ring into our glasses.
Here is the result:

2017. május 23., kedd

Cyclone PCB Factory 3.

I finished (almost) the mechanical build:

I'm quite happy with it. This is the first time when my son helped me with my projects. :-)

There are two things I want to check/correct in this build:

  • I wasn't able to buy M3 grub screw. So I assembled with normal screws and adjusted the gear placement for it. I'm not happy with the solution, so I'll try to get grub screws somehow.
  • The Z axis threaded rod maybe to long. I 'll check when I put the Dremel in, and adjust the size.

2017. május 22., hétfő

Cyclone PCB Factory 2.

I started to assemble the Cyclone.
How does it look like now:

When I tried to assemble the moving bed (Y axixs),  I realized, that it has a problematic design. It is only designed for a single size PCB. If I want to mill varying sizes, I've to change it to something else.
So I designed a different one:

It is able to lock various PCB sizes.
I started to print the parts of it.
It looks like the Geeetech printer struggling with some challenges:

I clearly know, what is the problem. This model has no object cooling. I'll design some for it, but not now. Actually, I know, how can I deal with this. So I was able to print this part finally.
The assembly comes later.

2017. május 21., vasárnap

Cyclone PCB Factory 1.

I've seen in someones post on the Facebook this:

I decided, that I want one.
As one of my 3D printers (the Geeetech) started to work. This time reliably. I printed out all of the required plastic parts. From that pink PLA. :-)

Yes, this picture was already published, but I habitually late with my posts.

2017. május 19., péntek

3D Printing failure

It looks like my printer struggling with some challenges today:

This is GT2 timing belt holder for my son's plotter.
This was the design:

2017. április 20., csütörtök

MVP Reconnect gift arrived

Finally my MVP reconnect gift arrived from Microsoft:

GeeeTech 3D Printer 7.

Yeah, facepalm.
This guy still struggling with that crap.
Many of my designs are come out from the printer seamlessly until I get into my mind to build a Cyclon PCB Factory (actually I seen in somebody's facebook post and checked, what it is).
It has several printed parts. When I started to print, at the second batch I got this:

Yes, you right it is the vengeance of the Cyclon PCB Factory because of the PINK!!!
So, I started to look around and read. I found two factors:
1. You should lower the temperature for PLA as it melts to long into the heatbreak and stuck in it if not flowing fast enough.
2. You should use some Canola oil, to prevent sticking the plastic into the heatbreak.
1. I went down to 195°C, and ordered a better fan for the heatbreak radiator (not arrived yet)
2. What a hell is that Canola. I looked around. It is called "repce" in my country. So bought a liter of it (there are no smaller available):

And the result is here:

Ok. But one good print doesn't tell anything. I achieved this in around three days without a single problem:

I guess. It is working now. Finally.

2017. április 19., szerda

GeeeTech 3D Printer 6.

When the shit hits the fan. :-D
As I tried to work with it. I had a small accident. Something was hitting hard the extruder fan while it was running:

The sad thing in it, that it was a Sunon Vapo fan, what I prefer, and had no more of this at home.

2017. április 18., kedd

Ergobag 1.

This is an old story. It dated back to the end of last summer. My two kids, who already in school has identical school backpacks but in different color.
These backpacks has a few places where stickers can be attached with velcro. The kids got some stickers with the bags, but these are just static ones.
Here came the idea. What if I create something personalized for them. Something with their own name, what even has some light in it.
So I needed a 3D Printed cage, with some electronics inside. To keep it simple I chosen an Attiny85 and APA102 LEDs.
I wanted something can be charged. To keep it as slim as possible, the normal AA or AAA size rechargeables was not really a good option (first I was thinking about, but finally I thrown the idea). So I chosen a Nokia BL-4C battery. There are two problems with it. You need a proper Li-Ion charger and as the LEDs need 5V, you need a boost converter to power it.
In addition I wanted to cut of the power after certain amount of time - Kids never switch of the toys.
So one push button for switch on, one for switch off if you want, and timed switch of by the MCU.
Here is the circuit:

I built this on a circular board:
(This is the first prototype, not the actual working one)

Then I designed a case for it.

Actually I was able to print the 3D parts and assembled the whole thing, but I wasn't really happy with the result as I had continuous problems with the 3D printer (the Geeetech, as the Robo3D was completely dead)
Finally the signs appeared on the bags, and the kids were happy with it:

The project was closed...
...but, as you can expect kids, are kids, and they have schoolmates. So "orders" arrived - who else needs it. :-)
All of the design files are available on my github:
It has been cleaned up, so just the actual design is in there.

2017. április 10., hétfő

GeeeTech roll holder

The GeeeTech printer came with a separate roll holder. It is uncomfortable to use and take unnecessary space.

To overcome this, I wanted to have something better.
My wife just thrown away this as the holder at the end was broken:

I decided to cut it into the desired length and design a holder for it, what fits onto the top of the printer.
The printer hase 4 holes at each side, I don't know why - no it is not he holes for the bowden extruder, different holes what I talk about.
So I designed a plastic part as the holder (two identical required), and printed.
Here is the result:

It is available on Thingiverse: http://www.thingiverse.com/thing:2235889