Sniffing Sunlight - Erik Kamerling

Explore the fascinating world of modulated light and its applications in covert communication through this ANYCon 2017 conference talk. Delve into the history of light-based communication, starting with Bell's Photophone, and learn about modern techniques for transmitting and receiving audio signals using light. Discover how to build basic Photophone equipment, including simple receivers and amplifiers, and witness demonstrations of audio modulated into ambient light. Investigate the potential of infrared lasers in surreptitious listening devices and explore natural reflections and attacking methods. Gain insights into cutting-edge applications, such as using smartphones as modulated light decoders, and understand the implications for security and surveillance. This talk covers both DIY approaches and commercial solutions, providing a comprehensive overview of this intriguing technology and its potential uses in various fields.

Background
The concept of modulated light
Roll your own
Buy commercial
Most lasers that are used in this capacity are infrared and very expensive
Infrared is used because the whole idea of a laser listening device, is to use it surreptitiously
The thing
Infrared laser range finders are almost a complete laser mic.
The precursor - Bell's Photophone
The Photophone continued
Building basic Photophone stuff
Building a simple receiver
Amplifiers
Demonstration of audio modulated • into ambient light
A morse type toy. Modulating thumps
Catching reflections
Natural reflections
Attacking with tape
Interesting examples of what's possible
Heliostats
Remember when we spoke about surreptitious attacks? • A Photophone receiver is surreptitious because it can capture from the environment at large. It does not rely on specifically arranged optics
How about this?
The smart phone as a modulated light decoder • This is really where it's at • Apps like Light Detector and Boop show what's possible via the light sensor on mobile phones
man's brush pass or dead-drop