szczys writes: There was this art piece that circled the internet a few weeks ago which used a tablet to visualize WiFi and other signals and it was complete fake. It was cool, and it approximated where radio waves emanated from, but it wasn't actually measuring them for display. Greg Charvat has built his career on Radar and other RF design. Seeing that demo he realized he could show you what actual microwaves look like. He used a radar that he built himself from coffee cans. By altering the circuit just a bit he is able to move the receiver around the room and illuminate different LEDs based on the signal traits. A long exposure photograph captures this and lets you see the radio waves. It's like a charcoal rubbing but for electromagnetic waves.