Written by InGuardians' Faith Alderson and Larry Pesce, VaporTrail is a tool for data transmission over FM, using RPITX to transmit from an out-of-the-box Raspberry Pi, and an RTL-SDR to receive. Twitter handles: @unknownloner, @haxorthematrix, @inguardians
http://www.electrodragon.com/product/fm-radio-module-rda5807m/