A bit of sample code that shows how Misty can read fingerprint scan data from an Arduino board through the UART serial port on her back.

Misty_GetFingerprintData_Sample.js

// ----------------------- Finger Print Sensor -----------------

// Updates the fingerPrintActivated key to set the state of the skill
// so that Misty is ready to receive data from the fingerprint scanner
_enableFingerPrint()
function _enableFingerPrint() {
    misty.Set("fingerPrintActivated", false, false);
}

// Starts Misty listening for data from UART serial. Data that comes in
// via serial is passed into the _backpackMessage callback.
_subscribeToBackpackData();
function _subscribeToBackpackData() {
    misty.ChangeLED(0, 0, 255);
    misty.DisplayImage("e_DefaultContent.jpg");
    misty.AddReturnProperty("backpackMessage", "SerialMessage");
    misty.RegisterEvent("backpackMessage", "SerialMessage", 50, true);
}

// Handles data passed in via serial.
function _backpackMessage(data) {
    // Gets the message.
    var status = data.AdditionalResults[0].Message;

    // If "PASS", you're all set -- access granted!
    if (status == "PASS") {
        if (!misty.Get("fingerPrintActivated")) {
            misty.Set("fingerPrintActivated", true, false);
            misty.ChangeLED(0, 255, 0);
            misty.DisplayImage("e_Joy2.jpg");
            misty.PlayAudio("accessGranted.wav", 100);
            misty.RegisterTimerEvent("resetEyes", 4000, false);
            misty.RegisterTimerEvent("enableFingerPrint", 3000, false);
        }
    } 
    // If FAIL, Misty takes your picture. Access denied!
    else if (status == "FAIL") {
        if (!misty.Get("fingerPrintActivated")) {
            misty.Set("fingerPrintActivated", true, false);
            misty.Set("pictureUse", "FINGER", false);
            misty.Set("pictureMode", true, false);
            misty.DisplayImage("e_JoyGoofy.jpg");
            misty.PlayAudio("accessDenied.wav", 100);
            misty.ChangeLED(255, 0, 0);
            misty.Pause(3000);
            misty.DisplayImage("e_SystemFlash.jpg");
            misty.ChangeLED(255, 255, 255);
            misty.PlayAudio("s_SystemCameraShutter.wav", 100);
            misty.TakePicture("finger", 375, 812, false, true);
            misty.Pause(200);
            misty.DisplayImage("e_SystemCamera.jpg");
            misty.ChangeLED(140, 0, 255);
            misty.Pause(500);
            misty.RegisterTimerEvent("resetEyes", 3000, false);
            misty.RegisterTimerEvent("enableFingerPrint", 3000, false);
        }
    } 
  catch (error) {
  }
}