Project Advice- motion sensor input

Hi folks

I'm completely new to Arduino so please be patient!

I have 4 audio tracks.
I have a PIR motion sensor, with a NC dry contact switch.

When the motion sensor is activated I would like the audio to skip to the next track.

Like I say, I'm completely new to this so my questions are very basic:

What Arduino hardware should I buy to allow this? I'm thinking the UNO will do the trick.
Will I need to use PD or similar to control the audio tracks or is there a better/simpler option?

Thanks!

What is PD stands for?
Google "arduino wave mp3 audio shield" , SFE(SparkFunElectronics) has plenty of them with example code.

I think PD means Proportional and Derivative. But if it is so I don't think you need to use PD.
You can simply use an external interrupt and skip to next track when ever the interrupt pin changes state or goes high.
The idea is you connect the sensor output to the interrupt pin and whenever it changes its state or goes high or low you make the audio track change.

ksp

Sorry guys- by PD I meant http://puredata.info/

It's similar to Max, which I thought would make a good option for playing audio files.

I have an Arduino UNO now though I haven't yet had a chance to plug it in!

You need to define, or at least to us, what is going to play the audio tracks. As you mention puredata, then one assumes its an external (to the arduino) device??

Texy

yes, sorry for being vague.

I will be running the software on a mac mini or similar, so I am completely flexible as to the best way to go about this.

I imagined I would connect the PIR to the Arduino.
When the Arduino detects and open contact it would somehow trigger the music playback software into skipping a track.

This is GREAT!

I've got my Arduino sensing the switch on the PIR, and I've got a serial data value every 2 seconds.

Now, in MAX msp, I just need a bang every time I get a "1" data value.

How do I read serial data on max?