Category: how-to

I just moved my site over from github pages to WordPress. In doing so, my post URLs changed, and I wanted to redirect so that visitors from search results wouldn’t hit a ‘page not found’.

My webhost uses cPanel, so I followed the instructions to set up 301 redirects for my pages. But they didn’t work! A bit of googling turned up that redirects don’t always work as expected when using content management systems like WordPress, but didn’t provide the answer. So here it is!

Because WordPress rewrites URLs so that it can handle pretty permalinks, your redirect (rewrite) rules must go above the WordPress section in your .htaccess file:

RewriteCond %{HTTP_HOST} ^heycascadia\.com$ [OR]
RewriteCond %{HTTP_HOST} ^www\.heycascadia\.com$
RewriteRule ^2014\/08\/08\/arduino\-wireless\-freezer\-alarm\/$ "http\:\/\/www\.heycascadia\.com\/arduino\-wireless\-freezer\-alarm\/" [R=301,L]
RewriteCond %{HTTP_HOST} ^heycascadia\.com$ [OR]
RewriteCond %{HTTP_HOST} ^www\.heycascadia\.com$
RewriteRule ^2014\/08\/19\/blackberry\-workgloves\/$ "http\:\/\/www\.heycascadia\.com\/blackberry\-proof\-workgloves\/" [R=301,L]

# BEGIN WordPress
<IfModule mod_rewrite.c>
RewriteEngine On
RewriteBase /
RewriteRule ^index\.php$ - [L]
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule . /index.php [L]
</IfModule>
# END WordPress

If they’re below the # BEGIN WordPress section, the URLs will be rewritten first, and then won’t match your redirect rules.

I’ve been working on a site recently for an open-source project, which is hosted using GitHub pages.

I struggled a fair amound with conditionals, and this is what I learned:

• Liquid doesn’t accept double-quotes for conditionals. You need to use single quotes.
• There needs to be a space between the comparison operator and the terms on either side. You can’t run them together without a space.
• You can use any YAML front-matter value, even custom values. For example, I used category: docs for pages that are documentation pages. I can access this later with page.category.

An example of all of this:

{% for page in site.pages %}
{% if page.category == 'docs' %} ... do something .. {% endif %}
{% endfor %}

The above works. What wouldn’t work:

// Need a space before and after operator.
{% if page.category=='docs' %}

// Double quotes are not supported; use single quotes.
{% if page.category == "docs" %}

It’s so obvious to everyone else, that I couldn’t find any reference to it on the internet: you have to solder an Arduino shield to the headers.

I thought it was plug and play, since the little header pins seemed very snug when I put the shield over the Arduino Uno. But the shield wasn’t working, and it turns out that each pin needs to be soldered.

Luckily, soldering is very easy, and I was able to do it in less than 10 minutes, never having soldered before. It’s worth checking out some YouTube vids before you start, though.

The other day I opened my deep freeze to discover everything inside slowly melting. The freezer had tripped the GFCI on the circuit, and silently turned off.

I don’t keep a lot of food in there, so there’s no real reason for a freezer alarm that will ping me when the temperature rises, but it was a great excuse to buy and tinker with an Arduino.

Here’s where I’m at so far:

Continue reading “Arduino wireless freezer alarm”