Reduce eye strain and insomnia when working at night with F.lux and Redshift

For thousand of years our days have been scheduled by the sun, so it is no surprise that our biological clock can be directly affected by the amount of light we get. Yet, our bodies can not differentiate sun light from artificial light, and in our modern societies we are surrounded by the later until the very last minute we go to sleep.

Melatonin is the hormone that tells our body when it is time to sleep, but it secretion can be affected by exposure to bright light, specially blue light of which we get a lot during day time, while red light, like that for example of sunsets, does not hamper our sleep cycle. The effect of light on our daily cycles has been studied by Harvard among others.

In this post I am going to talk about software to automatically reduce the amount of blue in your screen without you even noticing it according to the time of day. Remember that screens produce any color by mixing red, green and blue light sources.

Optimize Archlinux's Pacman

Pacman is a packet manager used by Arch Linux and all it's derived distributions. It is the equivalent to apt-get from Ubuntu, and as all packet managers in Linux, allows us to easily install most common, and sometimes uncommon, packets (program) without needing to scour the web for them as in other operating systems.

Pacman is already really fast and many people think it the perfect package manager (me included). However, you can tweak it's performance even further.

For spanish readers, take a look at [frikinux]'s post. He's who told me about reflector, which we will use to get faster downloads from closeby mirrors.

Electronics tutorial: an intuitive idea of what voltage is

This time I am going to talk about voltage, trying to give the most intuitive intuitive interpretation possible: potential difference.

Actually, voltage is the potential difference between two points in an electric field per unit of charge. Does this sound familiar? Here is a clue: cinematic potential energy is the potential difference between two points of a gravitational field per unit of mass.

Electronics tutorial: basics and Ohm's law

This is the first post about a series of mini basic-electronics tutorials I intend to write. Many of my friends, some engineers, some not, are starting to play around with Arduinos and other microcontrollers; and although they are doing quite well with the programming part, they still struggle to understand why you have to connect everything to ground, what a pull-up resistor is or how Pulse Width Modulation (PWM) works. But first we have to start with the basics.

In this post I am going to talk about voltage, current, resistors and Ohm's law.

Book recommendation: Leviathan series by Scott Westerfeld

Imagine how different World War I would have been if the Central Powers had had huge steam-powered battlemechs and fought against genetically modified beasts big as towers controlled by the Allies.

Surrounded by the tension of the war two characters emerge, Price Aleksandar of Hohenberg, who has no right to the throne yet is forced into hiding from the noble families of Austro-Hungary, and Deryn Sharp, a 15-year-old Scottish girl who wants to join the Royal Air Service to serve on an airship despite that women can not join the military.

7.1 surround sound on Linux

I was having trouble setting up surround sound on a PC with an integrated Realtek HD Sound Card ALC898. My problem was that although I had a 7.1 soundcard and a 7.1 sound system, not all my speakers where playing.

After checking pulseaudio I noticed that my soundcard was detected only as 5.1 compatible but with two audio inputs, so I was left with the task of turning one of the inputs jacks into an output (preserving one of the inputs for my microphone).

Solving Antergo's "Signature is unknown trust"

Antergos is a Linux distribution based on ArchLinux, in a similar fashion of how Ubuntu is based on Debian.

If you are using Antergos, you will have noticed errors due to wrong or unknown authentication keys when performing a full-system update, with an error message similar to "Signature is unknown trust". Luckily this is quite simple to solve.