![]() I found that the signals sent always start with a long "on", followed by the signal repeated again and again. It just transmits signals by sending long or short pulses - just like morse code. So this signal is transmitted with what is called On-Off Keying, which is what almost all wireless devices use to communicate. I was then able to see the waves of the signals in Audacity:įurther zooming in, I could finally see the individual bits being transmitted: It's also important to set the Encoding (32-bit float in my case) and Byte order (Little endian on Intel) correctly. I also found it's best to set the channels to 1 - Mono. Make sure the sample rate is set to 2000000 (2 million samples per second), to match the rate at which it was recorded. The next step was to import the signals into Audacity like this: I recorded the signal sent by the remote control for both ON and OFF for each of the 3 outlets (so a total of 6 signals). It saves the radio signals to a file - /tmp/radio_signal.dat.It records 2 million samples per second (something needed for importing into Audacity).It records at around 315 MHz, the frequency at which the remote transmits (which I found by looking up it's FCC ID code online).So first I recorded the signals of the different outlets with this Gnu Radio Companion flowgraph:Ī few things to note about this flowgraph: So I had these remote-controlled outlets (which I bought at Home Depot):Īnd I wanted to see what their wireless communication looked like. Gnu Radio is the main software I use for receiving and transmitting radio signals, but I've found Audacity, a program meant primarily for editing sound files, to be a great program for viewing and editing radio signals. ![]() You can capture radio signals with Software-defined Radios (SDR), such as the HackRF.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |