Hearing Ethernet Packets with an ESP8266 and RTL-SDR

Over on YouTube CNLohr has posted a video showing an interesting side effect of implementing ethernet on the ESP8266. The ESP8266 is a very popular $7 wifi module for microcontrollers that has found a lot of extra use outside of its intended design. Previously CNLohr also showed how Analogue NTSC TV could be broadcast with the ESP8266. Recently it was found that (software based) ethernet capability could be hacked into it.

In his new video CNLohr demonstrates that AM radio can be broadcast by attaching a short wire antenna to the ESP8266 ethernet output, and then using an RTL-SDR to receive one of its harmonics at 150 MHz. He shows that by varying the size and speed of the packets he can change the received tones, and even create notes to play music. This essentially gives a simple way to ‘hear’ ethernet.