Category Archives: Software

Electronics Project #8: Debugging the Symbol Keyboard Mini Project JMP001 | In The Lab With Jay Jay

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This post is part of my video blog and you can find more information about this video over here.

You can support this channel on Patreon: patreon.com/JohnElliotV

Silly Job Title: Component Wrangler

In this video I add improved debouncing logic to the inaugural Silicon Chip and Jaycar Mini Project: JMP001.

Shout out and thank you to Tim Blythman for developing this project.

You can see Tim’s original code and my updates which improve the debouncing implementation.

In the video I mention that we use the pgmspace.h header from Arduino.

Thanks very much for watching! And please remember to hit like and subscribe! :)

Following is a product I use picked at random from my collection which may appear in my videos. Clicking through on this to find and click on the green affiliate links before purchasing from eBay or AliExpress is a great way to support the channel at no cost to you. Thanks!

Maxitronix 500 In 1 (500in1) Electronics Project Lab KitThis is an image of the product.notes

Let’s go shopping!

Jan Axelson on USB (and Serial)

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This week I discovered Jan Axelson. She’s a tech writer and her website is here: http://janaxelson.com/.

I have ordered four of her books:

Subversion @ GitHub

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I wanted to use Subversion to checkout one of my GitHub repo branches, because an svn checkout only downloads the files it needs, not a full copy of every file ever added. But I discovered that GitHub sunset Subversion integration earlier this year. Sad face. Still, I suppose the economics justify that decision. As a consequence of my research, which was a bit sketchy because there is still heaps of documentation out there referring to the GitHub features which no longer exist, I did happen to learn about:

My use case for git submodules

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I have been chatting on IRC about how I’m learning git so I can use submodules and my friend @indigo wants to know my use case, so this post makes some effort to explain that with reference to one specific example.

I have a web framework/toolkit I am experimenting with called Mudball which is here: https://github.com/jj5/mudball

I use Mudball in (some of) my web projects, for example: https://github.com/jj5/www.jjlab.net

In the main project (in this case www.jjlab.net) I have a copy of Mudball in the ext/mudball directory. At the moment ext/mudball is setup as a git submodule.

I open the main project in my IDE (or text editor) and I want to be able to work on both the main application and the web framework/toolkit at the same time. Then when I’m done with some changes I want to run my `gui` script (it stands for “git update interactive”, not “graphical user interface”) which will increment my version numbers in inc/version.php and ext/mudball/inc/version.php and then add/commit/push any changes in both the main project and the web framework/toolkit.

The code for the `gui` command is here: kickass-libexec/bin/lx-gui.sh, it mostly just defers to lx_vcs_sync() which is here: kickass-libexec/src/2-module/vcs/vcs.sh.

The code which updates the version numbers is here: kickass-libexec/bin/lx-version-increment-patch.sh, it mostly just defers to other modules which are here: kickass-libexec/bin/libexec/version-increment-patch.php and here: kickass-libexec/bin/libexec/inc/version.php.

I have been using a similar setup for a long time with Subversion which uses the svn:externals facility (in place of git submodules) and I have a few scripts which help me manage that. My main tooling for this is known as svnman which is a bunch of scripts I wrote myself: Svnman.

I figured out how to avoid connascence of position

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Instead of passing positional arguments to constructors (or functions), instead pass a list of value objects. The type of the value object will tell you the type of the value, so you don’t need to worry about the position. This is a super powerful means of supporting back-compat within your code base so you can move ahead at speed. Having value objects instead of simple types (bools, ints, floats, strings, etc) might have performance implications, but it also can be quite handy. So far so good for my use cases.

Symbol Keyboard | Mini Project JMP001 | Learning Electronics In The Lab With Jay Jay

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This post is part of my video blog and you can find more information about this video over here.

You can support this channel on Patreon: patreon.com/JohnElliotV

This is the inaugural Mini Project! I introduced the Mini Projects recently. They are developed and published by Silicon Chip magazine, and sponsored by Jaycar Electronics (which is an Austrlaian electronics store, similar to Radio Shack in the USA, hopefully it doesn’t end up suffering the same fate.)

In this project, codenamed JMP001, we develop a USB keyboard which can send interesting and unusual symbols (which aren’t usually available on a keyboard) to a Windows computer using the alt-codes that it supports in a typical codepage.

For this first Mini Project I felt it was important to actually buy my components from Jaycar which I did for roughly eighty Australian dollary doos. Approximately US$50. The parts I ordered were these:

Belatedly I did also search for rubber feet.

There was quite a lot that went into the production of this video, and we accumulated a lot of links. Those are here:

In the end this first project was relatively successful, and we did get it to work fairly well on one of my Windows computers. As for the rest you can find out for youself in the video!

Thanks very much for watching! And please remember to hit like and subscribe! :)

Following is a product I use picked at random from my collection which may appear in my videos. Clicking through on this to find and click on the green affiliate links before purchasing from eBay or AliExpress is a great way to support the channel at no cost to you. Thanks!

Yum Cha HSC8 6-4A Ferrule Crimper KitThis is an image of the product.notes

Let’s go shopping!

Getting info about recent core dump (on Debian)

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This is a note for Future John about how to report a recent coredump (with debugging symbols) on Debian:

DEBUGINFOD_URLS="https://debuginfod.debian.net" coredumpctl gdb

Then bt is a magical gdb command to run to give you the call stack of the thread which… failed?

New Book Teardown #5: Electrical Engineering 101 3rd Edition (2011) | In The Lab With Jay Jay

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This post is part of my video blog and you can find more information about this video over here.

You can support this channel on Patreon: patreon.com/JohnElliotV

In this video I take a look at Electrical Engineering 101: Everything You Should Have Learned in School…but Probably Didn’t 3rd Edition written by Darren Ashby and published in 2011.

In the book the author mentioned that they used to write for chipcenter.com which appears to have since been taken over by EE Times. ChatGPT provided more information.

The author also mentioned Mathcad. I’m planning to check that out over here: https://www.mathcad.com/

And some terms which came up (ChatGPT explains further):

Vcc
Voltage at the collector
Vee
Voltage at the emitter
Vdd
Voltage at the drain
Vss
Voltage at the source

Thanks very much for watching! And please remember to hit like and subscribe! :)

Following is a product I use picked at random from my collection which may appear in my videos. Clicking through on this to find and click on the green affiliate links before purchasing from eBay or AliExpress is a great way to support the channel at no cost to you. Thanks!

Yum Cha 100pcs Releasable Cable OrganizerThis is an image of the product.

Let’s go shopping!

Fixing duplication in HTML title element for WordPress with Yoast SEO installed

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I was having a problem in WordPress for my blog where the title contained duplicate values, like “John’s blogJohn’s blog”.

The fix for me was to edit wp-content/themes/twentyeleven/header.php and disable a bit of the output, as shown below. I basically just added an if ( false ) to disable the code which caused the duplicate content.

This seems to effectively mean that Yoast SEO is in charge of the titles now. You can configure separately the homepage, posts, and pages titles in the Yoast SEO settings. I configure mine in Yoast SEO Settings / Content Types like this:

Homepage
Site title Separator Tagline
Posts
Title Separator Site title
Pages
Title Separator Site title
<title>
<?php
  // Print the <title> tag based on what is being viewed.
  global $page, $paged;

  wp_title( '|', true, 'right' );

// 2024-07-14 jj5 - OLD: I removed this because wp_title() (above) does everything that needs to be done.
if ( false ) {
  // Add the site name.
  bloginfo( 'name' );

  // Add the site description for the home/front page.
  $site_description = get_bloginfo( 'description', 'display' );
  if ( $site_description && ( is_home() || is_front_page() ) ) {
    echo " | $site_description";
  }

  // Add a page number if necessary:
  if ( ( $paged >= 2 || $page >= 2 ) && ! is_404() ) {
    /* translators: %s: Page number. */
    echo esc_html( ' | ' . sprintf( __( 'Page %s', 'twentyeleven' ), max( $paged, $page ) ) );
  }
}
?>
</title>