Problems with adding listener to PalmDirectionDetector script

[manjusrix]

Hey guys,

I am using the PalmDirectionDetector to detect a palm down and up gesture. The detection works well attaching a script to my GameObject. However I am now trying to do this using code but I face an error when trying to attach a listener to OnActivate(). Is there something I am doing wrong? Btw, using the 3.2 version of the SDK that comes with Unity 5.5.0f3.

    PalmDirectionDetector pdd; //class
    public IHandModel rightHandModel; //HandModel

void Start () {
    controller = new Controller();
    pdd = new PalmDirectionDetector();
    pdd.PointingType = PointingType.RelativeToHorizon;
    pdd.Period = 0.1f;
    pdd.OnAngle = 45;
    pdd.OffAngle = 65;
    pdd.HandModel = rightHandModel;
    pdd.OnActivate.AddListener(p2); //This line causes an NullReferenceException saying this was not initalised.
}

    private void p2()
{
    Debug.Log("Detected!");
}