Mostly Harmless

Mostly about my amusement

Category: Geek (page 2 of 36)

June 4, 2017

Next time can it yell “Danger Will Robinson!” instead?

Yesterday I went to work at a data center in NJ. I don't often go as the round trip is more than 5 hours on the road. I had to do some heavy lifting and I wasn't sure if I had access to the last place I needed. So my pal walked me to the man trap there so I could check.

Man traps worked like this: I badged into the trap, the first door closed me into a small room. I badged to a second door, added another type of mandatory authentication and the second door would open. If it didn't work then the first door will unlock and I would have had to exit and try again. Or I just didn't have access and I wasn't getting in.

I did this. The second door opened. Sweet! I walked through and waited for my friend to join me.

Once I closed the second door on the data center side, the LCD panel lit up RED and the speaker started loudly repeating these words.

PIGGY BACK ALERT! AN ATTEMPT TO PIGGY BACK INTO THE DATA CENTER WAS MADE!

That happened. It was loud. It did not stop, it just yelled at me on a loop.

The stern recorded voice just kept repeating that. I was in the data center and the door would not open to let me exit. There was an emergency open door exit button for safety but there was no way I was going to set off that alarm too. I was not in any danger.

I had to call my pal on his cell. He was on the other side of the man trap and he could not come in either. The speaker was on both sides and we were both getting yelled at by a recording.

In short, I put that section of the data center into lock down mode.

What happened was that the first door's handle was not quite in the fully reset position. The door was locked magnetically (I checked) but it wasn't considered fully closed. When I went past the second door pandemonium was the result.

A security guard came and reset the system. He was a good sport about it and it happened to other people before. I tried a couple more times just to be safe. It was all good now.

I'm just glad the local cops weren't called. That would not look good on my next employee review.

April 23, 2017

I think she gets it from her Mom

My daughter and a lot of her friends have begun to follow different K-pop bands. Putting aside that none of them understand Korean, they like the visuals and the beat of the music. And some of it is sung in English.

My daughter is crafty and I don’t just mean her attitude. Today she’s attending a birthday party and her friend is a big fan too. She took a small binder and using a word processor on the iMac made a 50+ sheet printed on both sides compendium of the bands they follow. Complete with the current band member bios.

BUT WAIT! THERE’S MORE!

She made stickers with the color laser printer and set them on the pages using Velcro. That way they can be re-positioned in different sections. The holes on each page and insert were done with a single hole punch.

She made folder inserts from stiff color paper and put printed material on and in them. She solicited her other friends to email her content and dolled that up too, formatting it so it printed and inserted correctly with the rest. She made a K-pop quiz complete with the answers in the back.

To make sure it’s a “living” book, she put all the document files and images on a USB drive that she’s included with the binder. That way the new owner can add or change the content as she sees fit.

I don’t know what to say. She draws and does crafts better than anyone I know.

Here’s a gallery of the book before it was given. I’m gobsmacked about all the attention to detail for this. She pulled all the images from online fan sites and formatted all the data.

I can’t wait to see what she does next.

March 14, 2017

3D Printing the WordPress logo in two colors

My 3D printer only supports having one filament loaded at a time and that generally means the objects I print is one color. I wanted the WordPress logo (naturally) and two colors would be cool. I can print pieces in different plastics and assemble them but sometimes you want one piece. Good news! My printer’s open source firmware supports changing filaments before the print job is done. That let’s me start the base in one color but switch to another before the print is completed. Here’s how I did it.

I downloaded the WordPress logo to my PC via Wikimedia in SVG format. SVG is a vector format for images that can be scaled without losing sharpness. I loaded that into Fusion 360 and deleted the text to the right and just kept the round logo.

In Fusion 360 I scaled the logo to 50 mm diameter. I then extruded the white portions in the logo to 3 mm. The circle outline and the space between the parts of the “W” were extruded to 1.5 mm. I exported that to an STL file and loaded it into Simplify 3D. This is where it gets clunky.

For slicing 3D prints into a format the printer can understand I use software named Simplify 3D. It’s not opensource (or cheap) but it’s very extendable and saves me a lot of time.

Simplify 3D supports scripts that use regular expressions to locate text in the generated G-Code output file and make substitutions. In the generated code it also comments each layer of the print so there’s a “layer 8” text where I want to insert printer commands to swap filaments.

Figuring that I needed to modify layer 8 was a pain. There’s probably a well documented way to do it but I sent my G-Code output file to Octopi. I loaded the file but did not actually print it yet.

OctoPi comes with a built in G-Code viewer. I moved the slider up until I found that layer 8 was where I wanted the change filament commands inserted.

I then deleted that file from the OctoPi, went back to Simplify 3D and in the process settings I went to Scripts -> Starting Script and added this to the “Additional terminal commands for post processing” field.

{REPLACE "\n; layer 8, Z = " "; layer 8\nG28 Y0 X0\nM300 S0 P1000\nM25\nG92 E0\nG28 Y0 X0\n; layer 8 "}

And generated and updated G-Code file with additional commands that I sent to Octopi. I loaded up a spool of blue filament and began printing. Midway through the print the extruder moved to the home position (but did not change it’s height) and waited for me to change the filament. Once I did that I loaded Octopi’s web page on my phone, logged in and clicked “Resume”.

The resulting prints came out well and I repeated the process with the white filament first. The bottom is one color and the top is another at just the right place.

This hardly took me anytime at all. It’s not a fauxgo, it’s a legitimate SVG (well, I hope it is) representation of the WordPress logo. The blue is a bit off but I can be forgiven for that. The PLA material is listed as “Egyptian Blue” and it’s the closest I had on hand.

There’s probably an easier way to get the layer accurately without using Octopi but it works. If I find an easier way then I’ll update this post.

What I really want to do is print the badges for the WordPress teams such as Support, Docs, training, etc. That’d be cool and I may do that this weekend.

This all came about because my brother got his 3D printer working in two colors on the same layer. His printer has two extruders and can print one color next to the other on the same layer. My printer does not do that but I’ll catch up. Competition is good. 😉

March 5, 2017

Pi Zero W makes for a compact Retropie box

Of course I did this with a Pi Zero W. 😉

One of the reasons I like the Raspberry Pi is that it lets you take hardware and turn it into a dedicated purpose based appliance. Cheaply! And one of those uses is to make a retro game system. I've used the Raspberry Pi Zero before but I was hampered by the fact that it lacks network and Bluetooth access. To get that you need to purchase a USB hub, wifi dongle and if you want it an Bluetooth fob.

The new Pi Zero W addresses that and adds both wifi and Bluetooth on the small package. Once it's setup all you need is an HDMI cable and power. That's it.

Here's how I did it with an 8Bitdo Bluetooth SNES style controller.

  1. Download Retropie for the Zero onto another Pi Zero (non-wireless one, I have a few). I could not get the image to boot on the new device so I setup a hub with a wifi dongle and keyboard on an old version.
  2. After the image reboots to resize the file system then F4 to get out of Emulationstation and on the command line run this command. 
 sudo apt-get update ; sudo apt-get -y upgrade ; sudo apt-get -y dist-upgrade ; sudo apt-get -y autoremove

That will take a while to run and you will need to read part of the upgrade and press Q at a point. That annoys me as those commands should run unattended. Meh.

The purpose of this is to get the underlying Raspbian OS up-to-date.

  • When you’re done run sudo shutdown -h now and swap the old Pi Zero for the Pi Zero W. Unplug the wifi dongle, you don’t need it anymore. Boot up the Pi Zero W with the keyboard attached via the USB adapter.
  • Once it boots up press F4 to get back to the CLI and run these commands. 
    •  cd RetroPie-Setup sudo ./retropie_setup.sh

    And select "U Update all installed packages" with your arrow keys. I don't know if that step is necessary but I do it out of habit. I like making sure I have the latest updates. That will take a long while too and reboot when it's finally done.

  • Update your new 8Bitdo controller to the latest firmware. On my Windows PC I updated my SFC30 to firmware 2.71.
  • Boot your Pi Zero W and press F4 exit Emulationstation and manually run the retropie-setup script again. Follow these instructions to connect your 8Bitdo controller and don’t forget to do the UDEV part. Reboot as needed.
  • Transfer ROMs via the wifi to your new device. I find that NES, SNES and Genesis games work well. MAME is a bit of dicey but older games played satisfactorily.
  • Connect to HDMI TV and have lots of fun.

    • The final parts list came out to this.

    Pi Zero W $10
    8Bitdo SFC30 Bluetooth controller $30
    Pi Zero Case I used one I 3D printed
    Mini-HDMI cable adapter $20
    2A micro USB power adapter $8

    I already had the cables and power supply but I'm trying to be complete. Not counting the case it's ~$70 for this one player setup.

    It's not a Raspberry Pi 3

    The overall experience is good and if you limit your retrogames to the older 8bit systems then you'll like it. But the Pi Zero W doesn't have all the CPUs and RAM of the bigger Raspberry Pi 3. The good Neogeo games won't play well. Sometimes sound suffers due to CPU use. Lag is a thing.

    But if you have the technical know how this beats the Nintendo Classic by a mile.

    November 13, 2016

    So! You like retro game systems?

    One of my recent hobbies (aside from breaking my WordPress site) is anything related to the Raspberry Pi. I use it as a network media player in my living room, USB computer on a stick and as a retrogaming console.

    Nintendo recently released the NES Classic Edition which comes with 30 built in games. This holiday season it will be a big hit and it sold out almost as quickly as it was released. With a Raspberry Pi 3 running Retropie you can accomplish almost the same thing. It just takes a little geeky work and some parts.

    Here’s the parts and links. I usually just drive out to Micro Center in Westbury and get it in person.

    Raspberry Pi 3 $29.99 Micro Center
    Raspberry Pi 3 case $8.99 Micro Center
    USB charger (5 volts, 2.4 amps) $8.99 Micro Center
    Microsoft Xbox 360 wireless controller for Windows 2 x $35.99 Best Buy
    32GB microSD Class 10 $10.99 Micro Center
    6′ HDMI cable $6.99 Amazon
    Total: $137.93

    OK, that added up quickly. The NES Classic Edition is $59.99. Add another $9.99 for a second wired controller and you’re only in for $69.98.

    I begin to see what Lily means. Grownup’ing is a pain.

    The XBox 360 wireless controllers that I linked to also include a USB transceiver. That part number JR9-00011 is cheaper than just a controller alone. I don’t know why.

    Just about any USB game controller that works with your PC will work with Retropie. I picked these because I had a spare and I like being able to sit on the couch while playing.

    Download and burn the Retropie image

    Visit Retropie’s download page and make sure you get the one for Raspberry Pi 2/3. At the time of this post that’s version 4.1

    I’ve never tried burning the image using a Mac. On a PC I just use 7Zip to expand the retropie-4.1-rpi2_rpi3.img.gz and use Win32 Disk Imager to write it to the microSD card.

    There are some really good detailed instructions for installing and configuring Retropie here.

    https://github.com/retropie/retropie-setup/wiki/First-Installation

    When it boots you will be asked to configure your controller so you’ll need to get your XBox 360 controllers working.

    I think the Xpad driver ships and is activated by default. I don’t recall activating it myself. If that’s not the case then I’ll update this post.

    1. Put batteries into your XBox 360 controller, and plug the XBox 360 Wireless USB transceiver into any free port on your Pi.
    2. Press the stylized XBox button on your controller to turn it on and then press the button on the transceiver.
    3. The front of your controller has a not quite recessed wireless sync button. Press that and your controller will connect to your USB transceiver.
    4. Press a button on your controller to begin configuring it.

    From the Retropie Git docs, you’ll configure the buttons like so.

    The image is from that Retropie installation page. I didn’t want to hotlink the image as that’s rude. If it’s a problem I’ll remove the image.

    You will get some of the button assignments wrong. Don’t worry, as long as you get the D-PAD, START button and A button assigned then you can redo it later on.

    That USB transceiver supports up to 4 controllers. When you use PS2 emulation for games it not only works but so does the rumble part. That’s cool.

    Network your Raspberry Pi 3

    I happen to have an Etherenet connection onto my Raspberry Pi 3.  It also comes with a built in 802.11n wifi adapter. You want your Retropie on your network and being able to ssh to it is very useful.

    https://github.com/retropie/retropie-setup/wiki/Wifi

    Borrow a USB keyboard from your PC or Mac so you can enter your wifi key. You won’t need it afterwards. I do all my Linux admin via ssh from my PC or Mac.

    Your Raspberry Pi 3 running Retropie is a Linux server. It’s running a Debian based distribution called Raspbian. If you’ve spent time administering an Ubuntu LTS VPS then this will feel very similar if not downright identical.

    The reason for getting your Retropie on the network is simple: once you do you will find a new Windows share at \\RETROPIE and you can deposit the NES ROMs you obtain in \\RETROPIE\roms\nes as easy as drag-n-drop.  You’ll have to do some research where to get them yourself. They’re not hard to find.

    When you do obtain NES ROMs make sure you keep them in individual ZIP archive files. Don’t extract them, just from them as is into your nes directory. Once you’ve gotten your roms onto your new system, press the “start” button on your controller and restart emulationstation.

    So many emulators to use

    Retropie supports many retro arcade systems. My favorite are MAME, SNES, NEO GEO and of course NES. I don’t play a lot of Atari 2600 games though I should. That’s one of the systems I had as a kid.

    The emulators are easy to use. Generally you just drag the ROM zip file into it’s directory. Use \\RETROPIE\roms\nes and \\RETROPIE\roms\snes for the  right one. You’ll see many more directories there but for now ignore them. You can explorer them later.

    This is not a game system for everyone

    If you are just looking for the classic NES games and can get your hands on one even with the small controller cables, then do so.

    This illustrative YouTube video can explain the mindset of people who do this sort of thing.

    https://www.youtube.com/watch?v=KxwcQ1dapw8

    You’ll either immediately understand where I’m coming from or you wont. That’s OK, some people just enjoy the nerdy aspects of things.

    Using a Raspberry Pi 3 with Retropie is purely a geeky exercise. It works, it works well. It’s easy to maintain provided you are willing to learn the Zen of the Debian Based Linux Server™

    Part of the appeal of the Raspberry Pi 3 is that it is a server with a quad core ARM CPU running at 1GHz. It has 1 GB of RAM built in. With a 32GB microSD card, case, and A/C adapter it’s a full on Linux server for less than $70.

    Setting up a small PC with similiar stats will run you at least $200. The small size of the Raspberry Pi 3 shouldn’t take away from the fact that it is a Linux server. It has a default user ID and password. You should change that if you’re concerned.

    Here’s an example of what I mean. Yesterday I did the following.

    1. ssh’ed to the retropie as the pi user.
    2. Ran sudo apt-get update ; sudo apt-get -y upgrade ; sudo apt-get -y dist-upgrade
    3. Ran cd Retropie-Setup then sudo ./retropie_setup.sh
    4. Selected “Update all installed packages” and skipped the OS ones because I already did those.
    5. Had coffee. See illustrative video above.
    6. Ran sudo reboot to reboot box.

    If you read that, stopped at step 2 and said “Are you kidding me?” then it’s alright. You’re OK. The NES Classic Edition is for you, it’s $60 and it is fire and forget. It does not have any network capabilities, it will never be updated. And there’s no legal question about using one either.

    If you want to roll your own and don’t mind getting up to your neck in Geeky Nerdy things then maybe the Raspberry Pi 3 is for you.

    October 23, 2016

    Scrape IFTTT Instagram media into WordPress

    I’m a photography nut. I love using my DSLR, I’m mad about film cameras and I use Instagram all the time. I’m also a WordPress user and I have a problem with Instagram: the photos are not preserved on my own site. To fix that I installed the amazing DsgnWrks Instagram Importer plugin and I’ve been using it for years.

    While testing WordPress 4.6 beta the plugin stopped working for me. I raised a support topic and I am convinced that my setup has changed. I do not doubt that the problem is mine somehow.

    I’m not proficient enough to locate where the break is and I really wanted to share my Instagram photos via my blog. So I created another WordPress account on my photo blog and with my IFTTT account I used this “Instagram to Blog” recipe. That worked, but it loaded the image from Instagram and used the IFTTT URL shortner for link.

    I really wanted a copy of my photo on my own server.

    I know less about IFTTT recipes than I do the plugin. But I do know how to use WordPress actions and filters so I wrote a small plugin to do the following.

    1. Via the publish_post action look in the content for Instagram image sources and extract those URLs. The wp_extract_urls function is made for this.
    2. When found import those into the WordPress Media Library and attach it to the post using media_handle_sideload.
    3. Make that new attached image the featured image for the post.
    4. Look for IFTTT short URLs and expand them using a simple function I wrote.
    5. Once that’s done then publish the post.

    You can view the code via this Gist link. I have that saved and activated as a plugin on my photo blog.

    This isn’t the ideal approach for me but it works. The IFTTT recipe successfully publishes a post when I submit a photo to my Instagram account. I’m taking that data and scraping images from another web site. Generally speaking that’s not cool but until I find a cleaner way to do it I’ll have to live with it.

    August 7, 2016

    Firefox and TLS

    Firefox is weird. In a forum conversation (which went so off topic but that’s alright) the following was reported to me. When you visited my site in Firefox, you get a warning about being insecure.

    Huh. That’s odd and a little embarrassing. I mean, I’m a network security professional so you can see how that would be awkward. 😉

    So I looked at my site on the Qualys SSL Labs page and got this result.

    Screen Shot 2016-08-07 at 9.35.58 AM

    Which is good but Firefox still didn’t like my site.

    A few weeks ago I was playing with my nginx config and something I did made Firefox unhappy. I’m pretty sure I munged the cypher suite in my poking and prodding.

    Fair enough, I used the configs from a site that does work in that browser and tonight I’ll play around to see what I broke. In the meanwhile my site is encrypted and viewable in Firefox.

    June 5, 2016

    Confirmed: I’m not getting the PC back anytime soon

    This may fall under category of "bad parenting" but probably not. I hope not. Just don't tell Lily, OK?

    My daughter saw all of the fun her brother has playing Team Fortress 2 and wanted in on the action. The kitchen iMac doesn't play games very well but my PC does. So I set her up on an account there, logged her into Steam and the rest was history.

    She picked up TF2 quickly. Then she saw that she could play Borderlands 2, Torchlight II, Portal 2 (is there a "two" thing going on?) and spent hours on the PC.

    Her normal activity is drawing on the iPad. She's really good and has developed a real skill. Video games are normally the domain of her brother. But they seem to like playing on the same TF2 server. When they're on the same team she plays the medic and supplies health to the other players. When she's on different teams she plays the scout.

    She spent the whole evening playing and I had no clue. It wasn't till I went to turn off the light in the office that I saw her. Her mother would not be happy had she walked into the room.

    There is hope that the has inherited Lily's Adult Supervision™ genes. I told her that I'd get a third PC for her, probably from Costco. Her answer?

    That's wasteful. I can share yours when you are not using it.

    I have no idea where she picks that stuff up. I've certainly never encouraged that sort of behavior.

    May 29, 2016

    I might be overthinking my son’s TF2 server

    My son plays Team Fortress 2 a great deal and wanted to host his own server with mods for him and his friends to play on. Rather than using his PC for that I created an account for him on the Linux basement server.

    I downloaded the Linux dedicated server, did a little port forwarding, a few small scripts with screen and POOF! he can now run and manage his own TF2 server. I need to email him some troubleshooting steps but it’s pretty basic even with SourceMods. It works.

    Except I’m using FIOS and my IP addresss changes from time to time. The basement server does update it’s DNS entry via Namecheap but TF2 favorites work by IP address.

    When the address changes the port forwarding still works but my son’s friends can’t find the server. The IP address changed and their favorite is gone. That sucks.

    IP Tables to the rescue

    I happen to have a fixed IP address on the Internet. This web server. I don’t have to run the dedicated server on my VPS, I just have to port forward TCP and UPD ports 27015 to the FIOS router.

    1. My basement server keeps the dynamic DNS name updated with the external IP address.
    2. My web server runs script every hour to see if the IP address changed for that DNS entry.
    3. If it did change then it deletes just the old iptable rules and re-add them with the new IP address.

    I found a useful bash script for targeting specific rules in named sections of iptables. Why re-invent the wheel? 😉

    Here’s the script.


    #!/bin/bash
    CURRENTIP=$(dig +short tf2.dn7.me | tail -1)
    OLDIP=$(</var/cache/tf2.dn7.me-ip)
    if [ "$CURRENTIP" != "$OLDIP" ]
    then
    # Delete existing /sbin/iptables rules for port 27015
    # From http://serverfault.com/questions/401416/iptables-clear-all-prerouting-rules-with-a-specific-destination-address
    # Remove PREROUTING rules for destination port 27015.
    for line_num in $(/sbin/iptables –line-numbers –list PREROUTING -t nat | awk '$8=="dpt:27015" {print $1}')
    do
    LINES="$line_num $LINES"
    done
    # Delete the lines, last to first.
    for line in $LINES
    do
    /sbin/iptables -t nat -D PREROUTING $line
    done
    unset LINES
    # Remove FORWARD rules for destination port 27015.
    for line_num in $(/sbin/iptables –line-numbers –list FORWARD | awk '$8=="dpt:27015" {print $1}')
    do
    LINES="$line_num $LINES"
    done
    # Delete the lines, last to first.
    for line in $LINES
    do
    /sbin/iptables -D FORWARD $line
    done
    unset LINES
    # Add /sbin/iptables of server's new IP
    /sbin/iptables -A FORWARD -d $CURRENTIP -i eth0 -p tcp -m tcp –dport 27015:27015 -j ACCEPT #forward tcp port range
    /sbin/iptables -A FORWARD -d $CURRENTIP -i eth0 -p udp -m udp –dport 27015:27015 -j ACCEPT #forward udp port range
    /sbin/iptables -t nat -A PREROUTING -d 172.99.75.122 -p tcp -m tcp –dport 27015:27015 -j DNAT –to-destination $CURRENTIP
    /sbin/iptables -t nat -A PREROUTING -d 172.99.75.122 -p udp -m udp –dport 27015:27015 -j DNAT –to-destination $CURRENTIP
    /sbin/iptables -t nat -A POSTROUTING -o eth0 -j MASQUERADE
    # Save the current IP
    echo $CURRENTIP > /var/cache/tf2.dn7.me-ip
    # Done
    fi

    view raw

    check-tf2-dn7-me-ip.sh

    hosted with ❤ by GitHub

    I registered the server on Gametracker and the banner works fine.

     

    It works and while the server’s actual IP address changes this will let others find my server. I only change my web server’s host once every few years so this will remain in place for a long time.

    They like Minecraft maps. I don’t know why but that’s alright.

     

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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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