Was reading an article about Subaru keyfobs having issues where anyone using a raspberry pi and a tv tuner can emulate one to break in to many of the Subaru range when I noticed that they were using the PI as an SDR (software defined radio) transmitter without any extra hardware.
Subaru full disclosure: [Only registered and activated users can see links. ]
Software: [Only registered and activated users can see links. ]
I have used a TV tuner as an SDR to receive various signals (can listen in to airport to plane comms and all sorts) and listened for radio signals but replaying some attacks meant you needed an actual SDR transmitter to send signals and the RFhack SDR is about £250. Turns out there is some software on the Pi you can use after connecting a wire/antenna to one of the pins to send out radio frequencies with no extra hardware.
RPITX - RF transmitter for Raspberry Pi: [Only registered and activated users can see links. ]
Thought that was pretty amazing. I managed to read some keyfob entry cards before but had no way to play back the signal to see if it would work but seems I might be able to use the Pi to do it.
Kinda amazed the Pi can do this.