sgtpepperaut

hi there, i am currently working on a project that involves a cellphone that puts out ~1.3 volts AC signal to the speaker/vibrator. I am trying to switch a 12 Volt standard automotive relay with whenever that vibrator/speaker goes off (ie when the phone gets called) wondering if anyone has any info on what hardware to use to make this possible. I was reading about transistors and MOSFET amplifiers but i am not quite sure that i can simply hook the ac source up to the base and have 12 volts at the collector putting out 12 volts at the emitter. Any info is appreciated! thx