def enroll():
    
    ## Enrolls new finger
    ##

    ## Tries to initialize the sensor
    try:
        f = PyFingerprint('/dev/ttyUSB0', 57600, 0xFFFFFFFF, 0x00000000)

        if ( f.verifyPassword() == False ):
            raise ValueError('The given fingerprint sensor password is wrong!')

    except Exception as e:
        print('The fingerprint sensor could not be initialized!')
        print('Exception message: ' + str(e))
        exit(1)


    ## Gets some sensor information
    print('Currently stored templates: ' + str(f.getTemplateCount()))

    ## Tries to enroll new finger
    try:
        print('Waiting for finger...')

        ## Wait that finger is read
        while ( f.readImage() == False ):
            pass

        ## Converts read image to characteristics and stores it in charbuffer 1
        f.convertImage(0x01)
        
        ## Checks if finger is already enrolled
        result = f.searchTemplate()
        positionNumber = result[0]

        
        if ( positionNumber >= 0 ):
            f.loadTemplate(positionNumber, 0x01)
            characterics = str(f.downloadCharacteristics(0x01))
            passhashes = hashlib.sha256(characterics).hexdigest()
            passhash = passhashes[0:32]
            print('Template already exists at position #' + str(positionNumber))
            return passhash

        time.sleep(2)
        ## Wait that finger is read again
        while ( f.readImage() == False ):
            pass
        ## Converts read image to characteristics and stores it in charbuffer 2
        f.convertImage(0x02)

        ## Compares the charbuffers and creates a template
        f.createTemplate()

        ## Gets new position number (the counting starts at 0, so we do not need to increment)
        positionNumber = f.getTemplateCount()

        ## Saves template at new position number
        if ( f.storeTemplate(positionNumber) == True ):
            ## Hashes characteristics of template
            
            characterics = str(f.downloadCharacteristics(0x01))
            passhashes = hashlib.sha256(characterics).hexdigest()
            passhash = passhashes[0:32]
            ## Hashes characteristics of template
            print('SHA-2 hash of template: ' + passhash)
            return passhash
            
    except Exception as e:
        exit(1)
        #print('SHA-2 hash of template: ' + hashlib.sha256(characterics).hexdigest())