Start/ stop 5v motor from headphones jack
simulate this circuit &ndash; Schematic created using CircuitLab

change the output to a tip122 transistor, connect the motor + to 5V the negative lead to the collector. also, try varying the size of c3 after reworking the output if it seems to sluggish.  Also, you can add a voltage doubler in there as well to give it some more drive level. I'll draw you the detector and output with a voltage doubler: