Category Archives: Infrastructures

How I activated my webcam and watched my room over the internet

Recently I managed to activate my webcam and see what is happening in my room over the internet. Here are the steps, in case I need them in the future:

  1. Dynamic DNS:
    • Use a Dynamic DNS service to access the computer, in case the IP Adress changes.
    • Update the IP with a script that runs over cron.
  2. Have a script in cron to connect to the internet in case the connection is down.
  3. Find out which microphone I want to use (I can use e.g. Audacity to find out which microphones are available). Note this to put it below in :input-slave=alsa://<here>
  4. Run the ssh deamon with /etc/init.d/sshd start
  5. [Check about Firewall?]

After these preparation steps, I go to the remote computer and:

  1. Access the  computer with ssh over the dynamic DNS address.
  2. Stream video and audio to the internet with a command like
    cvlc
    v4l2:///dev/video0
    :input-slave=alsa://hw:1,0
    --sout '#transcode{vcodec=mp1v,
    acodec=mpga,
    ab=128,
    vb=1024}:standard{access=http,
    mux=mpeg1,
    dst=:1234}'
    (put it all in 1 line)
  3. Start VLC on the remote computer and watch the stream like <dynamic dns address>:1234 (or any other port that I have put in dst above)

The black holes of the email communication

I would define an email black hole (EBH) as an email address or a website, who receives email about an issue but does not answer (to the surprise of the sender). In this case, an EBH is the opposite of a spam server: it absorbes unexpectedly instead of emitting unexpectedly (or in the language of vector fields, spam functions as a source and EBH as a sink).

Some examples from my personal experience (all in Berlin):

  • Once I wanted to go to the dentist of the university clinic. I used the email option of the clinic in order to make an appointment. They never answered.
  • Once I wanted to complain about the problematic delivery of a newspaper and used their email form. I was never informed if anybody read it.
  • Once I wanted to see a lawyer and used her email form. She never replied.

Which consequences has this behaviour? That almost everybody offers an email contact option (no matter if they actually support this option), because they don't want to give the impression that they don't move on. And one liar brings millions of others behind him.