Privacy Monitor

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Privacy Monitor
Something is wrong.jpg
A private monitor for... your privacy!
Privacy rules!
Patrick Juhl

Privacy Monitor[edit]


Build a privacy monitor of which the display is only readable if you are using an appropriate polarized filter

Why ?[edit]

Some would say because we can, others for porn. Well, the truth is none of these but rather because I was asked to build a prototype for Columbian artists that might be willing to give me a flight ticket to come over and solve it in person.

Why do I share this here ? Well because it involves hacking, hackers and was built in the hackerspace with bits and pieces "found" here and there.

Finally, although it is not a very ambitious project, the result was really good and it was fun to make and I am hoping that you will like it.


This project didn't suddenly show up in a dream but rather was found on the amazing Internet, really well described and documented. It could actually be summarized in two steps: Strip the screen and assemble glasses. But that was not the case for me as I chose, not so actively, to take a few more steps to have something a little more challenging to do.

Phase 1 - Strip...[edit]

Not you, the monitor. Typical LCD monitors usually have their glass surface covered with two layers, a polarized filter and an anti-glare surface. Remove them both very carefully by starting in a corner with a box cutter of some sort. When possible, grab it with your hands and carefully peel it off. A good tip is to pull at an angle to the screen that takes the peeled filter as close to the screen as possible. This will both make it less likely to break the screen and will leave a minimal amount of glue residues.

If glue remains, you can use towels soaked in paint thinner to clean it off as described in the original example.

Phase 2 - Realize... (optional)[edit]

...that not only this screen that you chose might not work but that you have no way to test it. And that in addition to that, you do not have a working power supply for it.

Phase 3 - Steal... (optional and depends only on phase 2)[edit]

...very shamefully a power supply from a working screen from somebody else's project, without asking for the permission and while that person is away in Amsterdam. And do this while knowing only too well what kind of mailing list ramble you might provoke.

Phase 4 - Realize again... (optional)[edit]

...that this power supply that you stole happily provides the backlights with juice (which happened to work, hurray!) but does not please the controller needed to display something on the screen. Yeah, too much privacy is a problem as well, you want to find the right balance, so...

Phase 5 - Find... (optional and depends only on step 4 )[edit]

...a controller that not only fits the screen but can be supplied by the partially broken power supply from the original, broken screen. If this is getting cryptic, check out the pictures in the result section. And yes your counting skills are alright, this screen now needs two power supplies.

Phase 6 - Assemble...[edit]

...everything together and create the specs. These can easily be made out of cheap 3D glasses from your local movie theater. Just pop out the filters and tilt them to the right angle to obtain a clear image. I used an angle of around 45 degrees and tape to keep them in that position. You can also buy your own filter and cut out some nice specs for a better looking result.

Phase 7 - Watch...[edit]

...people stare at your white screen and think you are crazy because you are wearing silly glasses with tape on.

Phase 8 - Close the tab... (strongly NOT recommended for your sleep and mental health)[edit]

...of firefox by accident and after only previewing the result of your almost done project page...


Quite satisfying I must say and I might just have got myself a flight ticket to Bogotà.

The pictures below demonstrate:

A privacy monitor in action Not so private anymore The illegitimate child of 3 incestuous screens

Watch it in action[[1]]

Acknowledgments (in order of appearance)[edit]

Instructables and Dimovi [[2]]

Ptr_ for his 3D glasses and thoughts

Olm for his amazing screen peeling skills and help

Dr. Pascaloïd for his incredible problem-solving creativity

Net_Runner for generously lending, without knowing it, a working screen from his project. I promise to put it back unharmed where I found it and buy you a beer for your contribution