/* */

DIY Emergency Lighting in a Crate (72+ hours)

Here’s a simple, yet often forgotten piece of emergencies, lighting. For the average person, electric lanterns, oil lamps, and candles are the norm. However, candles and oil lamps pose a fire hazard and electric lanterns don’t last long. For ham radio, I already heard many stories of folks going out to the field and end up using a flashlight for everything. In fact, it’s not practical for primary use in ham radio field work once you have your station and table set up – you can’t keep hold your flashlight, operate your radio, and take notes at the same time. Of course, keep a flashlight or 2 around (carry one) for temporary search/task lighting, but have more stationary alternatives as well.

Enter a portable and compact portable lantern solution that is easy to build from off-the-shelf parts, adjustable for task or room/tent lighting, lightweight enough for transport and heavy enough for stationary use, packs away into itself, and the best part: can run for over 72 hours of continuous use!

Partial List of Materials:

  • Small Plastic Crate
  • LED racing/show lights for cars (Walmart)
  • 3/4″ or 1″ PVC pipe, couplings, end cap, and cross joint
  • Plastic zip ties
  • Sealed Lead-Acid Battery, Non-spillable (9 AH)
  • Zip cord
  • Female blade connectors
  • Anderson Powerpole connectors
  • Solder, flux, heat shrink tubing
  • Screw, nut, washers, popsicle sticks
  • Velcro straps
  • In-line ATC fuse holder w/ 2A fuse

Put them all together and you have something like this:










For reference, the LED lights come in a pair and draw about 117 mA each. For a single lamp and a fully charged 9 AH battery, this is over 72 hours of runtime.

REMEMBER TO FUSE YOUR BATTERY POWER SUPPLY. I used the smallest fuse available (2A) for this application. I also highly recommend using the permanently bonded Anderson Powerpole connections as shown. Powerpole connectors are gender-less and polarized so it allows quick, secure, and proper connections without much guessing. The permanently bound version also minimizes the chance of polarity errors and allows you to insert a retaining clip to hold the two connectors together.

Made your own version or the same one? Need some help making one? Feel free to share and discuss in the comments section. As always, 73s!

Ham Radio Category Added

It’s been a while since the last update, but I plan to post more often soon. In addition to the computer related topics like before, I’ve added a new category to the mix: Ham Radio. That’s right, I recently got my Ham Radio license (Extra class)! As usual, all things I learn, build, discover, etc pertaining to ham radio will be posted under here. This includes things such as emergency preparedness/communications/operations, electronics, and radio communications. Since there isn’t a lot of content here yet, it will all be lumped into one category for easier browsing.


Dual-stack IPv4 and IPv6 DNS Servers (Linux)

It is inevitable that the change to IPv6 will need to be done in the near future. But in the meantime, it is also inevitable that you will need to run both IPv4 and IPv6 at the same time (at least in most scenarios). This leads to some caveats when it comes to DNS resolvers/clients.

Under normal circumstances, reputable public DNS servers running on IPv4 are able to resolve and respond with AAAA records, despite running on IPv4. This allows you to continue using your regular DNS settings.

However, you might be thinking: Why not use IPv6 DNS servers? I mean, that’s the whole point of switching, right? You can definitely use IPv6 DNS servers (and I encourage you to do so), but there is a catch, which is especially noticeable on Linux based systems.

Given you are generally familiar with DNS and network technologies in *nix, using IPv6 DNS servers should just be a snap: just add them to /etc/resolv.conf and voila, they’re enabled!

Wrong! Well, not exactly. If you simply append your IPv6 DNS servers to the list and your IPv6 does indeed route to the internet properly, you will notice a very large delay when doing DNS resolutions. This is because the IPv6 protocol takes precedence by default and it won’t be able to connect to your IPv4 DNS servers, which were listed first. If you have multiple IPv4 namservers defined, DNS resolution may just timeout and everything that depends on it will break.

The resolution is to make sure your IPv6 DNS servers are listed FIRST, ahead of your IPv4 DNS servers. It is also a good idea to add “options single-request-reopen” to have the same socket used for both IPv4 and IPv6 lookups, to work around cases of broken implementations. An example of a resolv.conf with both IPv4 and IPv6 Google Public DNS servers looks like this:

options single-request-reopen
nameserver 2001:4860:4860::8888
nameserver 2001:4860:4860::8844

Obviously, yours may vary. Hope this helps, and happy IPv6 surfing!

VMWare ESXi 5 Auto Start/Shutdown

VMWare recently, (and quietly) published a patch I have confirmed will resolve a guest virtual machine startup and shutdown issue that was introduced in March 2012 when they released Update 1.

The issue was that it broke the automatic startup and shutdown of the guest virtual machines when the host machine boots or shuts down. This did not affect enterprise customers who use a cluster, but vastly impacted many of us running individual nodes. Not surprisingly, this only affected the free version of the hypervisor and took 4 months before they decided to fix it due to 1.) community outrage and 2.) the issue extending to some paying enterprise customers.

The patch is ESXi500-201207001 and can be found here: http://www.vmware.com/patchmgr/download.portal. Just search for ESXi 5.0.0. Please note that if you aren’t running the latest patch before this one, you will need to update them sequentially before applying this patch.

As a note to the folks at VMWare: You guys barely averted losing your edge as a virtualization market leader due to angry users. This is not the first time either.

NetBeans 7 and Java SDK (JDK)

Recently I update to the latest NetBeans 7 installation and set it to use the Java 7 SDK (JDK). When launching the program, I get frequently got this annoying error message that says “JVM creation failed”, followed by an exit of the program.

Numerous articles and postings advise to edit the netbeans.conf file and change some memory parameters, but those did not work for me. I found the solution to be to install and use the SDK that matches your OS architecture, especially if you’re using a 64-bit environment. While you can’t use the 64-bit JDK on a 32-bit system, the opposite is possible but leads to random memory quirks like this one.

CONCLUSION: use the 64-bit Java SDK on a 64-bit machine. You might want to install the 32-bit Java Runtime (JRE) for compatibility reasons, and it will run alongside the 64-bit JDK + JRE just fine.

ALSO: I updated my NetBeans and JDK to get around the issue where NetBeans would not retrieve directory listings over FTP. I went from NetBeans 7.1.1 and JDK 7u2 to NetBeans 7.1.2 and JDK 7u4.

That’s all. Happy developing!