Mostly Harmless

Mostly about my amusement

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November 6, 2022 / 2 Comments

Oh, I do have a WordPress Blog.

It’s been ages since I last posted on my blog and I had been wanting to start again. What to talk about?

The Great Twitter to Mastodon Migration of 2022!

It’s not exactly a migration, it’s more like a mass exodus.

For anyone who’s not aware, Elon Musk completed his purchase of Twitter on October 27th, 2022. This was met by a lot of concerns from Twitter users. He likes to proclaim that he’s a “free speech absolutist” and if you think that means hate speech, anti-wokeness and anti-cancel culture then you are not wrong.

Note: “Wokeness” and “cancel culture” is not a thing. it never has been. Consequences, however are real.

In his first week he posted a nonsense conspiracy reply back to Hillary Clinton and subsequently deleted it. That was not bad but instead of apologizing for spreading that nonsense, he just kept mum. I’m glad he deleted it but, really how dumb do you have to be to go that way?

Then there was the matter of paying a monthly fee to get a “Blue Checkmark™”.

Putting aside the tone deaf “lords & peasants” nonsense, the idea is you pay and you get a blue checkmark seal of approval and other benefits.

It’s an awful idea. First, the existing blue checkmark was to let people know they were reading tweets from a verified person.

Do you follow Jeri Ryan? I do; she’s very cool.

The check mark is to let you know, that’s not a scammer pretending to be Jeri Ryan. Here’s her reply about the $8/month idea.

Verification has always been dodgy on Twitter. The rules changed, sometimes Twitter verified people and sometimes they did not.

The Blue Checkmark is not about spam or bots. It never has been. It’s about validating who that celebrity is.

Anyone who has had to deal with trolls and abusers know this is a bad idea. A scammer or phisher who pays for bulletproof hosting is not going to have a problem with $8/month if it helps them make their target dollars per month.

No one Begrudges Twitter Being Profitable

Twitter is (now) a private company. I don’t know if it has ever been profitable but Musk bought it for $44 billion and that was financed. Making money is a valid goal. This blue checkmark idea is just bad and no one should sign up for that.

Any website owner knows, advertising is king. No one likes ads. No one likes that a website shows me ad for that electronics I was browsing on Amazon. It is creepy. But it is an accepted way to make money on the Internet.

Elon Musk’s way of handling advertisers is typical Elon Musk.

That’s just a nonsense reply. Anyone who thinks it’s a “free speech in America” issue is not from this planet.

Just look at Ye’s troubles. Kanye West has lost major endorsements because he spews unapologetic anti-Semitic hate speech. Why would any brand want to be associated with that?

That’s always been the concern with Twitter being taken over my Elon Musk. Twitter has always been a hellscape when it comes to abuse. Sometimes they nailed it, other times they would routinely punish the wrong person and give the abuser a pass. With his treatment of hate speech/misinformation being “free speech” (it’s not) who wants to posting ads on that platform?

Mastodon is Federated and That’s a Good Thing

My first day really using Mastodon went like this.

  • I posted some toots. They’re called “toots”.
  • Someone replied at me “You smell Jewish” and their profile made it clear they were into “free speech”.
  • I reported them, added a couple of their posts that used the N-word to the report and blocked them.

It’s the Internet and I expected abusers. With a federated model I was not sure my report would mean anything. I was wrong!

Somewhere an admin got that report. They looked at it and I am sure they said “Oh. Yeah. That’s bad.” and banned the user.

There was no “We received your report”, there was no “That user does not violate the TOS”, they just dealt with it. Cool.

I’ll maintain both my Twitter account and my Mastodon account for now. It’s not a big deal, I do that today with Facebook and Twitter. I can be found at this URL.

https://mastodon.xyz/@jan_dembowski

Mastodon

I’ll see how it goes. Mastodon is currently a little slow and sometimes times out on me. That’s OK! That means people are joining it and that’s a good problem to have.

January 20, 2019

New Life for old 3D Printers

I’ve used and abused my first 3D printer for about 2 years. It had print quality problems and my recourse was to buy a new cool delta printer. But is there any way I can refresh that 3D printer I just about gave up on? I decided that an updated firmware may be something I wanted to try out.

Safety is an Optional Feature?

I don’t really know if temperature safety protection was available when my printer was originally made but it is now. Some manufacturers still turn that off and that’s insane. What that feature does is have the controller see how long it takes to reach a set temperature. If it takes too long, if the temperature results don’t make sense then the firmware powers off the heating elements and locks up the printer.

Shutting down your printer is a more attractive outcome than burning your house down. This is one reason why you want to buy safe equipment from reputable manufacturers. And even then, some of those manufacturers disable that safety check.

I ran into an issue like this with my 3D printer about 2 years ago. Too much power was going through a cheap connector for the hot end nozzle and the connector on the control board melted. The whole basement filled up with the smell of burnt plastic and I thought the inside of the controller box was on fire. It wasn’t quite that bad but close.

I don’t know if thermal protection would have stopped that melted connector but I do know that after a period of time the printer would safety off when the temperature didn’t make it in the window of time.

The manufacturer sent me a Melzi 3.5 replacement board and I swapped it out. I also added hardware to make the printer safer.

  1. One MOSFET to the rescue. I added it between the printer’s hot end and control board that drew power directly from the power supply. That meant the control board didn’t feed a lot of amperage, it just signaled the MOSFET to draw power separately and send it to the hot end.
  2. The 3D printer’s firmware lacked basic thermal protection that more current models have or should have in 2019.
  3. Leveling the printer bed was ruining my liver. 3D printing relies on getting a good first layer. Everything is literally built upon that. The way you level the bed involves turning the screws on each corner. Sometimes it works but often (for me) it didn’t. I could get part of it to work OK but then “RRAARRR!! WHY WON’T YOU WORK ON THAT PART OF THE BED!!?!”


I really wanted to try an updated firmware so I followed this video very carefully. It’s the exact same process as burning a bootloader onto an Ender 3 but this video matched my hardware. I bought an Arduino UNO R3 from Microcenter and went to work.

This process will put a bootloader on the controller. It will also brick your printer as you are wiping out the existing firmware. For me that was fine as I gave up on the printer and this was just the first step. I skipped the part about burning the Repetier firmware as I wanted straight to Marlin.

I found a pre-made version in this Google Group. It was Marlin 1.1.8 and it just worked. I took the author’s Configuration.h and Configuration_adv.h files and manually edited Marlin 1.1.9 (I wanted to see what I was doing) and now I am running that version.

I also replaced the 3D printer bed surface. It’s a sticker with Buildtak like surface. My old one as looking like the surface of the moon and was frequently failing. This is a re-usable part and is like getting new tires for your car.

Manual Mesh Levelling

This is how I previously leveled my printer’s bed.

  1. Remove the filament from the hot end and clean the nozzle with a metal brush while hot.
  2. Move the printer head to home. That’s the front left corner.
  3. Adjust the front left corner by turning the screw. This moved the corner up or down.
  4. Using a piece of paper, move the bed till there was just a little pressure on the paper. I wanted the paper to move without bunching up but get a little drag.
  5. Move the hot end to the next corner and repeat.

This works sorta, except that moving another corner also moved the level on the other corners so I had to revisit each corner multiple times to make it work. For added benefit, my bed was slightly warped. What was level at the corners wasn’t level at the middle.

I would get around that by using a raft on my prints but I’d prefer to just print reliably on the print surface directly.

Here’s how I do this now. This is using a current feature of the Marlin firmware.

  1. Heat up and clean the hot end nozzle and remove any filament. It’s metal and the wire brush works.
  2. Adjust the 4 corners to close to the homed nozzle and visually level. I just get it close to the nozzle. I don’t worry about how close, it’s within a millimeter or two and that’s fine. I think the firmware has 4 mm of play but I’ve not confirmed that.
  3. Heat the bed and the nozzle. I use PLA so that’s 60C and 205C.
  4. Select level bed on the LCD panel. This homes the nozzle and asks me to to click when ready. It will probe the height of 16 points (4 x 4). I set this in the firmware’s Configuration.h file.
  5. I click and it moves the hot end to the first point. Using the LCD knob, I raise or lower the nozzle (not the bed corners) till it’s just dragging on the paper underneath. When it’s just right I click to let it know.
  6. I repeat this for the next 15 points on the print bed.
  7. Save the settings when done.

This is what the mesh points look like.

Send: G29 S0
 Recv: State: Off
 Recv: Num X,Y: 4,4
 Recv: Z offset: 0.00000
 Recv: Measured points:
 Recv:         0        1        2        3
 Recv:  0 -1.07500 -1.02500 -1.02500 -1.07500
 Recv:  1 -0.80000 -0.75000 -0.75000 -0.82500
 Recv:  2 -0.55000 -0.52500 -0.55000 -0.62500
 Recv:  3 -0.40000 -0.42500 -0.50000 -0.60000
 Recv:

The bed goes from a -0.4 mm to -1.075 mm adjustment. See the second line? The edges are slightly higher than the middle. It’s imperceptible to a person but for a machine that’s laying down a layer of filament 0.25 mm thick it counts.

To enabled this feature, right after my print’s G28 code, I need to add “M420 S1” and that tells the printer to use the mesh I manually probed. I updated my slicer’s profile and started a test print and waited.

Great Shark Monkeys. That worked.

Test print on the 3D printer bed

I haven’t been able to get a good first layer like that in ages. I would get one side leveled but between the too low or high on the other side. And the low sections in the middle was awful. Now the printer gets the geometry from the mesh level I set and poof! A good first level is accomplished on the whole bed. Sweet.

I did the firmware upgrade mostly as a “Why not?” and to see if I could get those safety features baked in. The manual mesh leveling is an added bonus and I now have a fully functional 3D printer which I had written off months ago.

December 26, 2018

Norton Security Premium Renewal Scheme

I’ve been using Norton security products since the time of the flood. It works, I have protection for the kids devices as well as mine. Every year close to the end of my subscription I get an email that goes like this.

Hi! Your Norton Premium Security subscription is about to expire! Please authorize this payment of $109. Oh, and your credit card on record isn’t valid anymore. We would have just charged you for the full amount but the number isn’t working.

Have you met our Personal Savior Lifelock™? Have you? HAVE YOU MET LIFELOCK? LIFELOCK! LIIIFFEELOOCCCKK!!!! PRAISE TO THE LIFELOCK!!!!

I may be paraphrasing it and/or exaggerating just a little. Not that much.

Last year I called them on the phone and got a very professional person and here’s how the conversation went.

Me: Why would I pay over $100 for that when for $50 I can get the same thing from Costco?

Norton Rep: It’s not the same thing and you do want to renew, right?

Narrator’s Voice: It was the same code, same product and same protection. From the same company.

I ended up getting a discount that matched Costco’s price. It’s been another year and my subscription is due again.

This week I had a repeat of that but instead of a phone call it was an online support chat. That’s cool, I prefer that as there’s not really a he said/she said possibility. We both kept a copy of the chat log.

Amazon had a deal for the same package except for 15 months of coverage and only for $35. With tax it came out to $38.01.

After some back and forth, the polite person inform me that if I did buy that, come back to the chat and reference the still open case. They could add that 15 months once I gave them the code and that’s exactly what I did. I’m good till April 2020.

Here’s where it gets weird. After I validated that my coverage for updates, A/V signatures, etc. was good I received an email from Norton complaining that my credit card info wasn’t good (the card was long cancelled) and that I risked not getting coverage. I went online and disabled automatic renewals.

I’m still protected but only until April, 2020. I can deal with that.

This is how Companies Lose Their Customer’s Trust

In the past I would have cheerfully left on automatic renewals. I think that Software as a Service (SaaS) is a good, sustainable business model. I just don’t like it when companies try to take advantage of me. I no longer trust Norton or their business practices.

Two years in a row I have had to contact Norton just to get the price that they should have offered me in the first place for renewal. They opted to try and get me to renew for $109 automatically. I saved $71 and got another 3 months of coverage thrown in by purchasing the same product from Amazon.

I feel like Norton would rather slip in that expensive renewal than give their customer a discount that I can get just by purchasing the exact same product from their retail channel.

Renewals are a big Part of a SaaS Business

It’s not just the initial sale that gets companies revenue. The renewals are just as important as the initial sale.

I use Cisco Umbrella (I am employed by them) as my main protection on the Internet. It’s the enterprise version of the free OpenDNS and it’s good. For protection I recommend everyone sign up at OpenDNS, install the IP Updater so your settings keep for your household and go. It’s amazingly effective.

I use Norton as a supplement to that protection. I use it out of habit in case there’s something that Umbrella missed. Umbrella has missed a thing, I review my Umbrella logs and Norton logs as well. The Bad Stuff is caught by Umbrella and that means my local copy of Norton never has to deal with it. Life is good.

Norton’s renewal process and pricing is making me re-consider that relationship. I won’t have to deal with this till 2020 but my memories are long and this process was tiresome last year.

If there’s something comparable that crosses platforms I use then I don’t see why I would consider renewing Norton any longer.

December 15, 2018

Octoprint and Reverse Proxies

I have two active 3D printers, each hooked up to their own Raspberry Pi 3 running Octoprint. I like to manage them from my iPhone when I’m about. I don’t want to expose my IoT devices to the Internet without some precautions.

Here’s how my Internet connected house is setup.

Simple network diagram

The diagram was created and edited in https://www.draw.io/ Free online tools FTW.

My FIOS router on the left listens on port 80 and 443 and forwards that traffic to my Ubuntu Linux Server. On that server I run Apache2 with mod_proxy enabled. 

I run ddclient to update a DNS name with my floating IP address. I use virtual hosts on the Ubuntu Linux Server to receive all external http/https requests. All http requests on port 80 get 301’ed to https on the same host. 

First setup https on the virtual host as you normally do. Before trying to reverse proxy, have a default index.html file and make sure that works. I use Let’s Encrypt for the TLS certificate as it’s free and easy to setup.

Here’s reverse proxy configrution. 10.1.1.17 is the internal IP address of my first Octopi. Make sure the DNS name is working first before trying to test anything.

ProxyPreserveHost On
ProxyPass "/"  "http://10.1.1.17/"
ProxyPassReverse "/"  "http://10.1.1.17/"

ServerName pi1.valid-dns-name.com

ServerAdmin webmaster@localhost
DocumentRoot /var/www/vhosts/pi1.valid-dns-name.com

<Directory /var/www/vhosts/pi1.valid-dns-name.com>
        # Options Indexes FollowSymLinks MultiViews
        Header always set Strict-Transport-Security "max-age=31536000; includeSubDomains"
        Options -Indexes
        AllowOverride All
        Order allow,deny
        allow from all
</Directory>
<Location />
        AuthType Basic
        AuthName "Wrapper Auth"
        AuthBasicProvider file
        AuthUserFile "/var/www/external.htpasswd"
        Require valid-user
</Location>

That <Location /> section on the bottom? That’s important. That’s the section that says “You need a password to access this URL” and protects the Octopi setup from passerby’s on the Internet.

What I tell you three times is true.

  1. Do not expose any IoT devices on the Internet without encryption and passwords.
  2. Do not expose any IoT devices on the Internet without encryption and passwords.
  3. Do not expose any IoT devices on the Internet without encryption and passwords.

It’s just a bad idea. The wonderful Gina Häußge who writes and drives the Octoprint software knows this and has an excellent guest post on her blog about that access. This post is how I accomplished the Reverse Proxy method.

The password is created using the htpasswd command.

$ sudo su - www-data -s /bin/bash -c "htpasswd -c /var/www/external.htpasswd bob"
New password:
Re-type new password:
Adding password for user bob
$

I sudo as the www-data user so that the ownership of that file will be set as I want it. This creates a file with bob and his hashed password in it. The AuthUserFile directive will use that. If you have a valid user ID and password, you get in. If not you don’t get access.

The configuration gets copied for a new Pi. Just change the IP and ServerName and you can re-use this for other Octopi installations. By having an encrypted password protected access to your Octoprint setups, you can monitor and control your 3D printers from anywhere you have Internet access.

December 14, 2018

New Kossel 3D printer

I’ve had my Monoprice Duplicator v2 for almost 2 years and it developed some problems.

  • The firmware lacked safety features I wanted. I could have (maybe) updated the code but I’m not sure how many features would fit. The board on it is an old Melzi clone and I would need to buy another board just to update that one.
  • The printer needed love and attention. I started getting layer shifts, the bed surface began to look like the surface of the Moon and prints started suffering from layer shift.
  • I really like 3D printers that auto-level (tramming) in some fashion. That’s my favorite feature on the Prusa Mk2s and it generally just works. Leveling this printer’s bed was a real challenge. 

When I started looking the Ender 3 was the low end printer to get. It looks modifiable and a friend of mine likes his. He also purchased a Kossel delta printer and I was hooked.

Mini-Kossel vs Cartesian

Most 3D printers have a rectangular or square bed that moves forward and back for the Y-axis. The hot-end (the part that extrudes melted filament) moves left right on a rail for the X-axis and that whole rail moves up and down for the Z-axis. 

What makes this printer different is that the bed does not move. The bed has a 240 mm diameter and is round surround by three columns. Movement is controlled by sliders on those columns moving up and down together. It’s very cool to see.

Since the bed does not move that makes what is being printed in place very stable. The head can move and I print infill at 100 mm/s. The perimeters of my 3D print are set at 50 mm/s but I can safely increase that to 80 mm/s without any worries and that’s fast.

ANYCUBIC Linear Plus Kossel

I don’t think the manufacturer produces this printer anymore. The support section is still there but it’s no longer listed as product. That’s cool; it cost me $218.40 with free shipping from Aliexpress.

The build took me about 90 minutes. The kit is already half-assembled and very straight forward. The end stops screws made me want to punch a kitten as the screws would not set all the way in. I will probably print new ones out of ABS and re-do them. Also not all of the screws or t-nuts were of the best quality and stripped easily. For what I paid I am not complaining.

I did a test leveling as detailed in Anycubic’s manual and looked for a kitten to punch. The process is just awful and resulted in a bad first layer.

Marlin 1.1.9 to the Rescue

I’m a big fan of opensource software and the process for leveling this printer with Marlin is detailed in this Youtube video. It was that video that convinced me to get this printer. Da Hai knows what he’s doing and has his configuration files available to download. My version is the larger size and I started to modify Marlin to adjust for my bigger version.

I promptly fell on my face too; I do not know what I’m doing in Marlin. Some searching and I found this excellent blog post which is a review of the same printer and how the author was able to upgrade to that version of firmware.

I tested, made a couple of minor changes such as the printer display name and adjust how auto-home works and poof! I updated the firmware.

Everything worked. I used the process from Da Hai’s video to measure the surface and printed away. It just worked. I’ve added Anycubic’s Ultrabase, re-leveled the print bed and just went.

There are some test prints that you do to make sure everything is working. I printed 3D Benchys, I printed a 6 gear bearing (it prints in place) and they printed fine. The measured bed leveling produced a perfect first layer.

Then I changed the PLA to some from Inland (I had been using the roll that shipped with the printer) and printed this print in place iris box. I have never been able to successfully print this one before no matter how I tuned my printers. You make some small cuts on the base and rotate the bottom from the top. I didn’t have much success in the past but the pieces always were locked together and would not move. The results were great. I had no problem with this one at all.

Printed in place iris box

There are some artifacts in the print but it works. The printer is very precise.

Not for a First 3D Printer

This is my 3rd filament 3D printer. I’m comfortable with compiling the firmware, with the assembly, etc. but I do not recommend someone buying a Kossel printer unless they know what they’re doing.

The manufacturer’s documentation was very good. The printer was easy to assemble. Without the new firmware, without the very helpful posts and videos, I may have had a much harder time at it.

Since I do have some experience I’m having a good time playing with this latest toy.

August 11, 2018

This is not a Gutenberg Review, It’s a Blog Post

WordPress users are fantastic. This review and how the reviewer brought it back. My reply is a blog post so here we are and below is my reply.

*Reads. STANDS AND APPLAUDS!*

Hello Jan. I usually write the text all in plain form inside a blog post, then split it with some h2 h3 h4 headings and adding images.

PERFECT! Seriously, thank you for that. 😉 I read many reviews and your reply cheered me up immensely. I’ll let more qualified people reply to that.

About this not being a blog, I beg you pardon if I was OT, but then please tell me, is there an official forum where WordPress users can freely discuss about matters like this?

I’m getting very off topic but the thing with blogs is that they frequently devolve into a mess of either positivity (never saw that myself but I’m keeping an open mind) or negativity (OH YEAH, ALL THE TIME!)

The https://wordPress.org/support/ site is divided into sections for support of the WordPress code, support of plugins and themes, and reviews which is feedback.

When someone leaves a review here it is not a blog post. It’s their experience for that theme or plugin. Though as you know we’ve good software for blogging about that.

If someone leaves a review that is substantive about that plugin or theme then that’s fantastic. Gutenberg’s 4.9.8 callout had the desired effect. People are trying it and for the most part even their 1 star reviews have provided good feedback to improve it.

If someone just vents, hate posts, rage replies then that’s not for here. I don’t think you’re surprised that happens. Such behavior has a limited value and a short shelf-life here. These forums are moderated and no, that’s not censorship in case anyone wants to chime in that way.

You left a review of reviews. I commented about that as a moderator. You replied in an excellent fashion and brought it back to feedback about this plugin and editor. Much thanks!

*Drinks coffee, probably too much but here we are.*

The people who are coding Gutenberg, who are driving it forward, who support the users, who are doing this on their own time for the community are good people. These forums are 100% staffed by volunteers. I know you get that but others will read this and again here we are.

For their efforts they generally get a “thank you” but some disparage them, cast aspersions on their intentions and motivations. The whole effort gets accused by some and something negative and those users are occasionally downright mean and cruel. That may get tolerated on some blogs but that’s abuse and isn’t tolerated long here.

*Finishes off coffee, I’m sure you see a theme with me.*

Thanks again for the update. It’s the weekend so someone may not get to it soon but you’ll get a reply about your experience and some follow up questions.

July 11, 2018

In America it’s pronounced “CUE”

I’m a little miffed and want to write this down.

My mother and I went to the local Giunta’s Meat Farms (it’s called MEAT FARMS, how can I not like that place?) and wanted to get a few bottles of wine. There’s a local wine and liquor shop on the other end of the same strip. We walked there to save time and a few miles.

This isn’t the place we normally buy wine at. Usually we go to a store on Old Country Road that is ran by a nice Korean American couple. They’re from Argentina and they speak Spanish perfectly. I’m ashamed of my 2 year-old level grammar when they speak. They’re nice and know their wine. Some of their recommendations have been very good.

The place we went today had a person who felt the need to educate my mother about wine and tried to convince her that she wanted a rosé. She doesn’t like that type of wine, said so and he continued his hard sell. She and I shortly told him “thanks, but we know what we’re looking for”.

Mom has been educated about wine well before he was born. I swear, he was mansplaining wine to her.

As we’re checking out, Mom asked him if the store carries Don Q rum. She pronounced it “don COO”. He looked at us weird and feigned that he didn’t know what we meant. Finally he says

Oh, you mean “dän CUE”. No, we don’t carry it.

To which I replied

We’re Puerto Rican, we pronounce it “don COO”.

No big deal, right? While we are finishing up paying for the wine, that’s when he explained.

In America it’s pronounced “CUE”. You can try stores in Brentwood or Wyandanch.

Oh. That’s how it is in “America”. Good to know.

A little background about Long Island. Both of those towns are considered “minority” places and not in a flattering way. You know when that Orange Racist, who’s also currently president, talks about MS-13? He’s usually using Brentwood as his example.

There’s nothing wrong with those places and yeah, we’ve been to both towns before. There are some amazing Hispanic restaurants in Brentwood.

As we’re walking out and I’m holding the door for Mom, she clearly says out loud:

We are never shopping in this store again.

Unless that person’s brain condition got to his ears, he received the message loud and clear. In America we can choose which stores we shop in. **** that guy and his racist attitude.

April 21, 2018

Time-lapse 3D printer videos

I have two 3D printers and each has a webcam. I use Octopi (Octoprint on a Rasberry Pi) and can stop bad prints from my smartphone if I need to. Some materials are difficult to print and hours into it I can cancel the print job. I tried attaching the webcams to the printer’s heated bed so that I can get stable time-lapse 3D printer videos.

This didn’t go too well. I have both printers in Ikea Lack table enclosures and adding an arm to the bed meant that the camera would smack into the front door of the enclosure. When the bed moved back and forth the camera shook. This made for blurry videos. To address this, someone came up with software to pull it off with a stationary webcam. It’s called Octolapse and you can review the code on Github.

Software Plugins to the Rescue

My favorite software platforms can be extended by add-ons or plugins. Octoprint is no exception.

The Octolapse plugin waits for an event in the print job, moves the bed and extruder to a position you set and then snaps a frame. I use when the layer change for that event. After the frame is snapped the print job resumes. When the layer shift happens again it repeats and snaps another frame.

The results are fantastic. I turned off autofocus on the webcam to prevent some blurriness. Here’s a time-lapse of a multi-color snake I printed. It took 6 hours and 45 minutes. The video is 6 seconds long. It’s not a tall print so there’s not many layers to snap images.

The default Octopi time-lapse print is 1 minute and 37 seconds long and looks like this.

I have not tuned the Octopi video settings and the quality isn’t very good. The reason that the Octolapse version is better is because it’s not a moving image exactly. It’s a collection of sharp still photos stitched into a single video.

This is a better solution than a moving camera attached to the print bed. You can put the camera anywhere and obtain smooth, sharp, time-lapsed videos of your prints. I will probably put my webcams on a small stand and position it closer to the bed for larger full results.

It does add a little time to the print because the plugin inserts the commands to move the bed and extruder, snaps a photo, then goes back to printing. For each layer this is repeated. But the prints typically take hours to print and the time added is negligible.

This is a very elegant solution. The plugin has profiles for my Original Prusa i3 Mk2s MMU and one for my Monoprice Maker Select v2. I’ve not sorted out the Monoprice (the bed needs leveling and isn’t working too well right now) but once I have, I’ll post videos from that printer too.

March 25, 2018

Yes, I use Facebook and I’m deleting their apps

Take a moment to peruse the story about Cambridge Analytica. One outcome of that is that I remain a Facebook user but their apps and data are removed from my phone. I recommend all people I know to delete their apps. Here's why.

Control what you share

I use Facebook for a number of reasons.

  1. My extended family uses it. I love my family, (yes, even you and especially YOU) and they use Facebook. As far as I am aware, my family extends from Puerto Vallarta in Mexico to Puerto Rico to parts of Asia and Europe. This is a very 21st century thing and it works.
  2. Many of my school friends use it and I like to maintain some form of contact with those people. I went to school with some very cool folks. 
  3. Support groups. I'm a 3D printer user (I can stop at any time, I am not an addict) and some of the most effective sources of information are on Facebook.
  4. SOCIAL ISSUE AWARENESS! That one deserves a shout. Many people organize and discuss issues that are important to me. Like it or not, my Facebook feed is a source of information about many topics. Gun control articles? Check. Liberal causes? Check. Funny kitten videos? Check, Check.

All that is valid and anything I put on Facebook I do so with full knowledge and forethought. When I upload an image, video, comment or post to Facebook I know what I'm doing. That is no longer something I control once I do that.

When I share something on Facebook I expect it to be innocuous. My phonebook isn't that.

What else is Facebook obtaining that I don't control?

Visit your Facebook settings page and download a copy of your data from Facebook. You can do so via this link. https://www.facebook.com/settings

Depending on how much data you've shared, that can take a while. Mine took 10 minutes before Facebook notified me the download was ready.

Download and extract that zip archive. Open the index.htm file with your browser and click the Contacts Info link. My whole smart phone address book there. This wasn't somehow cross indexed from other users, I 100% never gave Facebook my cellphone number. If they got that, it wasn't from me.

They have the number of my employer's travel booking hotline. Really? I only added that a few weeks ago when I had to fix some work travel bookings in a hurry.

They could have easily gotten my own moble number from users who mistakenly uploaded that via the Facebook Messenger app as apparently I did. I'm reasonably sure that is how Facebook harvested my phone's data.

This is something that I take great care to not do. That's a line too far for me to cross and I do not want Facebook, or any social media site to get phone numbers, names and email addresses from me. I routinely tell the LinkedIn app the same thing: stop asking for that info.

And yet, there is my phonebook in my Facebook data download. I've tried to eliminate it from Facebook and I have not succeeded yet.

They know which apps I've installed too

Now visit the Applications link on your downloaded data. That is a historical list of applications on phones that I've wiped and disposed of years ago.

There's even more there about what ads I've looked at, etc. but I'm OK with those. I don't mind anyone tracking what I do on their site. It's not my site and that I can retrieve that data is a good thing. I don't think Facebook is "E-V-I-L" but when it comes to data collection I think they're stunningly blind to what they are doing.

"You are not a Facebook user, you are a Facebook product."

That's entirely correct and I don't disagree with that.

In the United States, data belongs to the person who collected it. That may not be true in other countries but within the U.S. that is 100% correct. This will not change as our government historically puts companies before people.

In Europe and other places, that isn't always the case. There are penalties for this sort of behavior. What I explicitly share on a site is acceptable. What the site backdoors from me is not.

I'll keep using Facebook from a web browser for now but there's no way I'll trust them on my phone again.

I want that contact data removed from Facebook. I want to believe that Facebook will honor that wish. But I have no reason to believe that they will do so.

You see, Mark Zuckerberg's statement isn't about Cambridge Analytica abusing user data. It's about how someone beside Facebook did that and was caught. It's just public relations now. If you are aware of that and are careful then you may want to keep using Facebook for now. But not on a phone, that trust has just gone out the window.

March 14, 2018

Wildcard certs via Let’s Encrypt

I just reduced 14 Let's Encrypt certificates down to 2. This is possible because the free service went live for wildcard certs. This has great implications for people who use the WordPress Multisite feature or routinely light up new virtual hosts in the same domain.

You can read Let's Encrypt's understated announcement here.

On my VPS I run Ubuntu 17.10 and it has a version of certbot that you can get from the official repo. Sadly, it's the 0.21 release and wildcard certs need ACME v2 support and that's only in release 0.22 and greater.

Here's what I did

On the command line I cloned cerbot from Github.

git clone https://github.com/certbot/certbot.git
cd certbot
sudo ./certbot-auto

You'll see something like so. On my main box it asked if I'm OK with installing more Python packages. A quick installation of those dependencies and I was ready to go.

Press c to cancel. You want wildcard not single hostname certs. Now type this as one line.

sudo ./certbot-auto certonly --manual --server https://acme-v02.api.letsencrypt.org/directory

The server argument is the important one and points to the new V2 API. I could modify the configuration but I'd have to remember what/where I did that. This is easier for me. Certs generated using the V1 API will work and renew with the new one so there's no worries there. The manual argument prompts you through the steps and ask what domains to use.

Normally this is not a manual process. But for the ACME V2 API, an additional check is required and I don't have a certbot plugin to interface with my DNS provider.

When prompted for the domain name I used "*.dembowski.net dembowski.net" and was instructed to create a DNS TXT record for _acme-challenge.dembowski.net as well as a file in dembowski.net/.well-known/acme-challenge/ with a generated name and content.

If you can put that file on the right web server, if you can update your DNS, then you're considered legitimate. Just make sure you wait for DNS to propagate first before proceeding. You can check if it has (at least for Google) using this link.

I have Namecheap and after a quick visit to that dashboard, I waited for the new TXT record to populate, I created that special file and hit enter.

POOF! My server was validated and the certificates were placed in /etc/letsencrypt and a few minutes later my many hosts were updated to point to that new wildcard cert. I repeated this for my other domain and I'm good.

WordPress Multisite and wildcard certs

If you are running multisite then this simplifies your life tremendously. You can and should have one virtual host for your installation. In my case, they're underneath *.dembowski.net.

In my nginx configuration, I modified the server_name line to add *.dembowski.net and I removed the other vhosts files. They were pointing to the same directory for WordPress and they're not needed anymore.

Less is more. I've been waiting for this since they announced it and lighting up new web server instances while maintaining transport level encryption is such a good thing. Let's Encrypt continues to make the web a more secure place.

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Jan Dembowski

Jan Dembowski

I am a software enthusiast who is easily amused and definitely mostly harmless.

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