What do i need to make a motion to audio sensor?

For a university project i need some sort of motion sensor which will activate a piece of audio when triggered. what do i need to make this? and where can i get these things?What do i need to make a motion to audio sensor?It depends what you want to accomplish, but probably you need proximity sensor

Look in electronics stores for "capacitive proximity sensor" or make it by yourself

You also can also use PIR sensor(motion detection) used in home security systems. It just need 12V DC power supply, and you can use its relay output as switch that will trigger audio device