5 ms·

Is it possible to do this across an entire monitor ? Could the NSA (or anyone else) be filming us through our screens ? "We see all through the black mirror"

ajuc 8y ago
Each pixel receives light from each point in the room, so almost all of them have the same value. You need a pinhole to block vast majority of that light, so that each pixel on screen receives light from a different point on the other side of the pinhole.
qmr 8y ago
Maybe, but why do that when you can compromise webcams and display cables?
- m1573rp34130dy 8y ago
  display cables can be shielded, webcams can be covered over removed or banned from office use...the whole tempest hacking thing was intended to be applied noninvasively from a suspicious icecream truck parked outside for the last 3 days...
m1573rp34130dy 8y ago
...if you work it for a while, you can image things in a radar like fashion. there was even a device that could be purchased that was a working television/camera, now obsolete...what you are suggesting requires physical compromise beforehand...
londons_explore 8y ago
I tried this on an oled display (by removing the controller and accessing row and column lines directly). Light certainly had some effect, but I didn't get to be able to have the display show something and act as a sensor at the same time (possibly because the capacitance of the row and column lines is too high)
- Sephr 8y ago
  What specific display did you try this with? Maybe µLED displays will eventually be sensitive enough for use as 3d webcams or pupil tracking for AR/VR. Capacitive touch screens in lenses can also track pupils using the shape of the eye.
  - DoctorOetker 8y ago
    I would love to learn more about using capacitive touch screen to track pupils. Is there a specific article or smth you can recommend?
tobyhinloopen 8y ago
Your OLED display doesn't have a lens though, so you would only see light differences
- amelius 8y ago
  The keyhole of the door could serve as a pinhole.

ajuc 8y ago

Each pixel receives light from each point in the room, so almost all of them have the same value. You need a pinhole to block vast majority of that light, so that each pixel on screen receives light from a different point on the other side of the pinhole.

qmr 8y ago

Maybe, but why do that when you can compromise webcams and display cables?

m1573rp34130dy 8y ago
display cables can be shielded, webcams can be covered over removed or banned from office use...the whole tempest hacking thing was intended to be applied noninvasively from a suspicious icecream truck parked outside for the last 3 days...

m1573rp34130dy 8y ago

...if you work it for a while, you can image things in a radar like fashion. there was even a device that could be purchased that was a working television/camera, now obsolete...what you are suggesting requires physical compromise beforehand...

londons_explore 8y ago

I tried this on an oled display (by removing the controller and accessing row and column lines directly). Light certainly had some effect, but I didn't get to be able to have the display show something and act as a sensor at the same time (possibly because the capacitance of the row and column lines is too high)

Sephr 8y ago
What specific display did you try this with? Maybe µLED displays will eventually be sensitive enough for use as 3d webcams or pupil tracking for AR/VR. Capacitive touch screens in lenses can also track pupils using the shape of the eye.
- DoctorOetker 8y ago
  I would love to learn more about using capacitive touch screen to track pupils. Is there a specific article or smth you can recommend?

tobyhinloopen 8y ago

Your OLED display doesn't have a lens though, so you would only see light differences

amelius 8y ago
The keyhole of the door could serve as a pinhole.