Encode videos to send via WhatsApp

WhatsApp currently is kind of picky about the video format that supports. To my knowledge only: MP4 (H264 + aac)

I use avconv to convert my existing video files:

INPUT_FILE=~/vids/ground_spiral.MP4

avconv -i $INPUT_FILE \
       -f mp4 -c:v h264 -b:v 1200k -g 300 -bf 2 -s 640x352 \
       -c:a aac -b:a 64k -ac 1 \
       /tmp/output.MP4

Install Hack Typeface on Ubuntu/Debian

Want to try Hack Typeface? Use the following gist:

Happy coding!

Add custom facts to puppet

Just needed a fast way to set up facts with a couple of commands on the machine where I'm using/testing puppet manifests.

Surprissingly I found what I was looking for digging in Vagrant code. Put your facts in environment variables, prefixed with 'FACTER_':

# Define your facts as variables
export FACTER_YOURCUSTOMFACT=value1
export FACTER_OTHERFACT=value2

puppet apply /path/to/puppet/test/main.pp

Happy testing!

Extracting RFID chip from SSS Siedle

At work we use RFID cards to get through the doors. I don't like to carry it hanging from the neck. I wanted to put the rfid card in my phone, which is the only artifact (beside my wristwatch) that I carry with me all the time.

One problem: the card is too thick to fit inside the phone. But it's mostly made of plastic, so my idea was to somehow extract the chip and antenna from the card.

If you have a Siedle RFID card, which looks like the picture, and want do do the same keep reading:

Electronic controller for the washing machine

The electromechanical timer of my washing machine died. It couldn't be repaired and had to be replaced.

What to do?

1. Be boring, go to the store, buy a new one, replace it
2. Build your own, even if you have no idea how

If you think the second option is the right one keep reading...

Biometric identification through door movement analysis

With my friend Julian we thought it may be possible to identify a person entering into a building from the way it opens the building's door, analyzing the angular values over time.

It's because of the differences between human beings (physical and psychological) that anyone of us interact with our surroundings in a very unique way. The key thing here is to be able to recognize patterns for each individual, and then use them as identification method.

Hack your monitor to hang upside down

For another project I was lacking enough room to put a CRT monitor and a PC on relatively small shelf. So instead of getting another extra shelf I decided to put the monitor on the bottom side of the shelf. Yeah :)

I just need to manage to invert the image of the monitor, to make some use of this fancy setup.

15 digit 7 segment display

To show some stats of my home server I end up building a nice 7 segment display with following specs:

• 15 digits (supporting all alphabet)
• flicker free
• doesn't require constant refreshing
• must be cheap (I'm a student)
• works with with the serial port
• modular (simply connect many of them to expand the display)