recently i came across some great software for xbox kinect so i decided to upgrade my preexisting face recognition project. the software is called artectid (the software is included in zip file).
things you'll need:
arduino
relay
optocoupler
computer
270 ohm resistor
diode 1n4007 or 1n4004
xbox kinect
{openni1.5.4.0
OpenNI-Compliant Sensor Driver v5.1.2.1} get them from here: http://www.openni.org/openni-sdk/openni-sdk-history-2/
and of course oem windows kinect sdk get it here: http://www.microsoft.com/en-us/kinectforwindows/develop/overview.aspx

arduino kinect face.zip
Download

Step 1: Shematic

First put together arduino relay switch like on shematic

Step 2: Uploading Arduino Code

int incomingByte = 0;

void setup() {
Serial.begin(9600);
        pinMode(12, OUTPUT);
}

void loop() {

if (Serial.available() < 1) {
          return;
          }

incomingByte = Serial.read();
if (incomingByte == 67) {
          digitalWrite(12,HIGH);
   delay(50000);
   digitalWrite(12, LOW);
          }

}

Step 3: Installing Drivers

first install windows kinect sdk http://www.microsoft.com/en-us/kinectforwindows/develop/overview.aspx
then OpenNI SDK v1.5.4.0. http://www.openni.org/openni-sdk/openni-sdk-history-2/
and after that OpenNI-Compliant Sensor Driver http://www.openni.org/openni-sdk/openni-sdk-history-2/
and of course artecid( ArtecWELCOME-v1.0.0.141-x64-de6d925.exe)included in zip

Step 4: Creating Task

next copy application.windows32 from arduino kinect face.zip to desktop. Then create task in windows task Task Scheduler it should look
like the uper images.