Show actual signal strength (in dBm) instead of little baubles on your iPhone

From baubles to dBm

If you’d like to see your actual signal strength (in dBm) on your iPhone instead of the normal little signal strength baubles, this is possible (though it’s a bit of a hack).

1. Enter Field Test Mode


Open up the Phone app and dial in *3001#12345#*, then hit Call .

Field Test Mode will open up immediately and you’ll see the signal strength in dBm in the upper left corner of the screen. Tapping the number (or baubles) will toggle between dBm and little baubles.

Field Test Mode

2. Make it stick

If you hit the home button and return to the home screen, the baubles will return, so don’t do that.

To make the signal strength stick:

  1. Hold the power button until the “Slide to power off” overlay appears, then:
  2. Release the power button and then hold the home button until the Field Test Mode quits

The signal strength should remain visible in the upper left corner of your screen, though I had to go through the whole procedure a few times before I got this to work (the first couple of times Field Test Mode just restarted instead of quitting).

What do the number mean?

Vin d’Alsace

Vin d’Alsace

Updated gem: nordea v2.0.1

If you’ve ever wondered why email parsing (or email address parsing) is so terrible, you should watch this video.

Ricardo Signes at YAPC::Asia Tokyo 2011

ngrok: like localtunnel but with request introspection

ngrok is a handy tool that let’s you tunnel your local ports on your development machine to the public Internet. In that way it’s similar to Progrium’s localtunnel, except it comes with a cherry on top: request introspection

When you start up a tunnel with ngrok (e.g. ngrok 3000), it also gives you access to a sweet web interface which let’s you inspect requests made to the tunnel.

ngrok request inspector

ngrok has binaries available for Windows, Linux, and OS X (I created a pull request to Homebrew to add a formula for ngrok, so installing it should be easier on OS X soon).

After you’ve checked out ngrok, you should have a look at my hobby project: Piranhas

Scanning some photos with my brand new film scanner

Scanning some photos with my brand new film scanner

Just loaded two rolls of film into my developing tank

Just loaded two rolls of film into my developing tank

Middleman on Heroku – 2013 edition

⚠️ This article is outdated, please see the Middleman on Heroku – 2017 edition post for a more up to date guide on how to deploy Middleman sites to Heroku.

In case you haven’t heard of it yet, Middleman is a Rack-based static site generator built in Ruby. It’s super nice to use, but deploying it to Heroku can bit of a black art.

This guide assumes a few things:

  • You already have Ruby, RubyGems, and bundler installed on your system
  • You know the basics of Git
  • You already have the Heroku Toolbelt installed and configured
  • You already have an Heroku account
  • You know the rudiments of creating apps on Heroku

Step 1: Install Middleman locally

If you don’t have it yet, you should install Middleman on your development machine:

gem install middleman

For more details on this step, read the the Middleman documentation.

Step 2: Generate a new Middleman project

Generate a new skeleton Middleman app with a name of your choice (I chose clever_like_a_fox)

middleman init clever_like_a_fox

This will generate a ton of output, like this:

middleman init

Ignore this for now, and just do cd clever_like_a_fox and open the project directory in your editor.

Step 3: The Gemfile

Modify the Gemfile to look something like this (the Middleman version may vary):

# If you have OpenSSL installed, we recommend updating
# the following line to use "https"
source ''

ruby "2.0.0"

gem "middleman", "~>3.0.13"
gem "rack-contrib"
gem "puma"

As you might notice, three lines have been added (ruby "2.0.0", rack-contrib, and puma). If you’re not using Ruby 2.0.0, you should set the Ruby version to the correct version.

Finally (for this step), run bundle install in terminal.

Step 4: The config.rb file

Next, we want to configure our app so that we get pretty URLs (no .html at the end).

In the config.rb file, around line #50, above the set :css_dir and set :js_dir lines, add the following:

activate :directory_indexes

Save your changes…

Step 5: The 404 page

We need to be able to give our users a nice error page if they go to a URL that doesn’t have content, so let’s create a simple 404 page file in the source folder (source/404.html):

<!doctype html>
  <meta charset=utf-8>
  <title>Page not found</title>
<p>The content you were looking for cannot be found.</p>

Once again, save your changes.

Step 6: The file

We’re almost there, just a little bit of configuration left!

Create a file in the root of your project and paste in the following code:

require "rubygems"

require "rack"
require "middleman/rack"
require "rack/contrib/try_static"

# Build the static site when the app boots
`bundle exec middleman build`

# Enable proper HEAD responses
use Rack::Head
# Attempt to serve static HTML files
use Rack::TryStatic,
    :root => "build",
    :urls => %w[/],
    :try => ['.html', 'index.html', '/index.html']

# Serve a 404 page if all else fails
run lambda { |env|
      "Content-Type" => "text/html",
      "Cache-Control" => "public, max-age=60"
    },"build/404/index.html", File::RDONLY)

Again, save your work.

Step 7: The Procfile

Create a new file called Procfile in the root of your project with the following contents:

web: bundle exec puma -p $PORT -e $RACK_ENV

Step 7: Deploy to Heroku

Woot! Almost there.

Add this line to the .gitignore file in the root of the project:


Run git init . in the root of your project, then commit all the project files:

git add .
git commit -am "Initial commit"

Create a new app on Heroku:

heroku create

Deploy your code to Heroku:

git push heroku master

Open the URI given to you by Heroku, or run heroku open in terminal in order to open the site in your default browser.

You should be greeted by a site that looks something like this:

Welcome to Middleman


Heroku recommends using Unicorn to serve Ruby/Rack apps, but I chose Puma instead as it is simpler to configure. This will probably work well for most use cases.

The source code for my sample app is available on GitHub: matiaskorhonen/middleman-on-heroku. The code changes after each step have been tagged, in case you want to browse through the history.

By the way, you should also take a look my hobby project, Piranhas.

The bundle_cache gem for Travis CI

gem install bundle_cache

You might remember my blog post on speeding up builds on Travis CI by caching the bundled gems to S3.

This strategy is now even easier thanks to Eric Barendt. He packaged up my scripts as a handy gem: bundle_cache.

In addition to not needing to copy-paste the scripts into your project, I also switched out the dependency on fog to aws-sdk. This reduces the number of dependencies needed on install and thus speeds up builds even further.

As an aside: You should also take a look my hobby project, Piranhas.

This design feels … fresh.

This design feels … fresh.