RV electrical

Posted onAuthornetjeff4 Comments

This is a summary diagram I created to help people new to RV's better understand the electrical systems in an RV.  The direction of the arrows shows the flow of power.  This diagram might not exactly match your specific RV, but the overall idea is applicable.  Also, this does not show all the details. The usual disclaimer applies, that  before working on your RV electrical systems you should get actual training, and consult the detailed diagrams for your specific RV.

If would like to print this, here it is as a Powerpoint slide.

Converting my Weber Q1200 to use both low-pressure RV connector and standard tanks

Posted onAuthornetjeffLeave a comment

Last week I converted our Weber Q1200 gas grill to use both the low pressure connector on our RV, and standard (high pressure) 1, 5, 10, & 20 lb tanks.

I followed the instructions in this YouTube.com video.  Here are the exact parts I bought on Amazon for the conversion, and hoses to connect to RV and standard tanks.

  1. Propane Quick Connect Kit – Valve & Full Flow Plug, by Camco (item # 59853)
  2. Brass Pipe Fitting, 1/4" male to 1/8" male, by Anderson Metals (item # 706123-0402)
  3. Brass Pipe Fitting, 1/4" female to 1/8" female, by FasParts (part # FP119-BA)
  4. Pipe Joint Compound with PTFE, with brush, 4 ounces, by Oatey (item #31230)
  5. Low pressure quick-connect propane hose, 12 feet, by DozyAnt
  6. 1 lb to 20 lb propane adapter hose ( 1"-20 female to QCC1 female), 4 feet

Grand Mesa

Posted onAuthornetjeffLeave a comment

In July we camped in Grand Mesa National Forest.

Red-tailed hawk

Posted onAuthornetjeffLeave a comment

We often see hawks circling, and there's a nest on the other side of the golf course.  But this evening one decided to hang out on our gate for a while.  I'm pretty sure this is a red-tailed hawk.

Should all locks have keys? Phones, Castles, Encryption, and You.

Posted onAuthornetjeffLeave a comment

Passing a law that requires companies to build devices with digital keyholes which only good-guys can use, is the same as passing a law that says the value of π (pi) must be exactly 3.

Here's an excellent short video about the literal impossibility of such laws, and the enormous risks of going ahead anyway.  Because unlike real-world keyholes where the bad-guy must be physically present at each keyhole they want to break through, in the digital world each bad-guy can simultaneously attack millions of digital keyholes from the other side of the world.  The end of the video says it best: "Anyone who says otherwise [that digital keyholes can be built which allow only angel good-guys while blocking demon bad-guys] is either ignorant of the mathematics, or less of an angel then they appear."

There's no math in the video, just really good explanation.

Using ExifTool to make .mp4 video file dates match contents

Posted onAuthornetjeff7 Comments

I had a bunch of .mp4 and .3gpp video files whose file "create" and "last modified" filesystem dates did not match the meta data inside of the file, and this was causing problems because many apps use the filesystem dates when sorting video files (rather than using the metadata inside the video files).

I found ExifTool could fix this.  Using the ExifToolGUI I could fix them one at a time.  By using the ExifTool cmd-line tool I was able to change them all at once.   The biggest challenge was that most of the documentation was on how to modify the internal meta data, but I wanted to "copy" from the meta data to the filesystem timestamps.

The first trick is to figure out what the "tags" are for the internal metadata and the file system.   I found the ExifTool FAQ #24 which shows how to query for the times:

> exiftool -time:all -a -G0:1 -s MyVideo.mp4

[File:System]   FileModifyDate   : 2014:09:07 19:35:32-06:00
[File:System]   FileAccessDate   : 2015:10:24 22:55:22-06:00
[File:System]   FileCreateDate   : 2015:10:24 22:55:22-06:00
[QuickTime]     CreateDate       : 2013:09:14 00:52:38
[QuickTime]     ModifyDate       : 2013:09:14 00:52:38

From the above the CreateDate & ModifyDate are the internal meta data, and the FileModifyDate etc are the filesystem.

So to update the filesystem date to match the metadata CreateDate I used this command:

> exiftool "-CreateDate>FileModifyDate" MyVideo.mp4

To modify multiple files I used wild-cards on the filename, like *.mp4 to update all mp4 files in the current directory.

=========================

Related, to update the file system time for image files to match the meta data:

> exiftool "-DateTimeOriginal>FileModifyDate" MyPicture.jpg

Note that most apps know how to look into image metadata, so setting the filesystem dates is not as important as for video files.

Better voting than "Winner Takes All"

Posted onAuthornetjeffLeave a comment

It's time for national elections in the US, and many citizens feel like they can't get good representation, no matter how they vote.  Much of the problem is our "Winner Take All" system of voting — it's easy to explain but has *huge* flaws.  Here is a series of 5 videos (total 28 minutes) that talks about the problems, and some much better (but slightly more complicated) alternatives.

A computer built out of dominoes?

Posted onAuthornetjeffLeave a comment

In the video below, a team built two computers out of dominoes.  The first was capable of adding any two numbers between 0 (zero) and 7 (seven).  The second computer they built was capable of adding any two numbers between 0 (zero) and 15 (fifteen).

The computer you are using right now, deep under the covers, does everything in terms of binary addition.  What about the other operations you ask?  Read More …