diff --git a/stt_engines/snowboy/main.py b/stt_engines/snowboy/main.py
index f2781d7..7dd2499 100644
--- a/stt_engines/snowboy/main.py
+++ b/stt_engines/snowboy/main.py
@@ -1,4 +1,4 @@
-import snowboydecoder
+import maindecoder
 import sys
 import signal
 
@@ -48,7 +48,22 @@ def detected_callback(modelid):
 
 sensitivity = sys.argv[1]
 sensitivities = [sensitivity]*nbmodel
-detector = snowboydecoder.HotwordDetector(models, sensitivity=sensitivities)
+# Trigger ticks:
+#   a tick is the sleep time of snowboy - argument of start()
+#   [0] ticks_silence_before_detect:
+#       min silence ticks before detection
+#   [1] param ticks_voice_before_detect:
+#       max voice ticks before detection
+#   [2] ticks_voice_after_detect:
+#       max voice ticks after detection
+#   [3] ticks_silence_after_detect:
+#       min silence ticks after detection
+trigger_ticks = [ 2, 10, 3, 2 ]
+
+detector = maindecoder.JarvisHotwordDetector(
+    models,
+    sensitivity=sensitivities,
+    trigger_ticks=trigger_ticks)
 
 # main loop
 # make sure you have the same numbers of callbacks and models
diff --git a/stt_engines/snowboy/maindecoder.py b/stt_engines/snowboy/maindecoder.py
new file mode 100644
index 0000000..facd3de
--- /dev/null
+++ b/stt_engines/snowboy/maindecoder.py
@@ -0,0 +1,268 @@
+#!/usr/bin/env python
+
+import snowboydecoder
+import snowboydetect
+import pyaudio
+import collections
+import time
+import os
+import logging
+
+logging.basicConfig()
+logger = logging.getLogger("snowboy")
+logger.setLevel(logging.INFO)
+TOP_DIR = os.path.dirname(os.path.abspath(__file__))
+
+RESOURCE_FILE = os.path.join(TOP_DIR, "resources/common.res")
+
+class JarvisHotwordDetector(object):
+    """
+    Snowboy decoder to detect whether a keyword specified by `decoder_model`
+    exists in a microphone input stream.
+
+    :param decoder_model: decoder model file path, a string or a list of strings
+    :param resource: resource file path.
+    :param sensitivity: decoder sensitivity, a float of a list of floats.
+                              The bigger the value, the more senstive the
+                              decoder. If an empty list is provided, then the
+                              default sensitivity in the model will be used.
+    :param audio_gain: multiply input volume by this factor.
+    :param trigger_ticks: ticks before triggering callback, tick is a sleep_time.
+                   [0] ticks_silence_before_detect:
+                       min silence ticks before detection
+                   [1] param ticks_voice_before_detect:
+                       max voice ticks before detection
+                   [2] ticks_voice_after_detect:
+                       max voice ticks after detection
+                   [3] ticks_silence_after_detect:
+                       min silence ticks after detection
+    """
+    def __init__(self, decoder_model,
+                 resource=RESOURCE_FILE,
+                 sensitivity=[],
+                 audio_gain=1,
+                 trigger_ticks=[-1,-1,-1,-1]):
+
+        def audio_callback(in_data, frame_count, time_info, status):
+            self.ring_buffer.extend(in_data)
+            play_data = chr(0) * len(in_data)
+            return play_data, pyaudio.paContinue
+
+        tm = type(decoder_model)
+        ts = type(sensitivity)
+        tt = type(trigger_ticks)
+        if tm is not list:
+            decoder_model = [decoder_model]
+        if ts is not list:
+            sensitivity = [sensitivity]
+        if tt is not list:
+            trigger_ticks = [-1,-1,-1,-1]
+        model_str = ",".join(decoder_model)
+
+        self.detector = snowboydetect.SnowboyDetect(
+            resource_filename=resource.encode(), model_str=model_str.encode())
+        self.detector.SetAudioGain(audio_gain)
+        self.num_hotwords = self.detector.NumHotwords()
+        self.trigger_ticks = trigger_ticks
+
+        if len(decoder_model) > 1 and len(sensitivity) == 1:
+            sensitivity = sensitivity*self.num_hotwords
+        if len(sensitivity) != 0:
+            assert self.num_hotwords == len(sensitivity), \
+                "number of hotwords in decoder_model (%d) and sensitivity " \
+                "(%d) does not match" % (self.num_hotwords, len(sensitivity))
+        sensitivity_str = ",".join([str(t) for t in sensitivity])
+        if len(sensitivity) != 0:
+            self.detector.SetSensitivity(sensitivity_str.encode())
+
+        self.ring_buffer = snowboydecoder.RingBuffer(
+            self.detector.NumChannels() * self.detector.SampleRate() * 5)
+        self.audio = pyaudio.PyAudio()
+        self.stream_in = self.audio.open(
+            input=True, output=False,
+            format=self.audio.get_format_from_width(
+                self.detector.BitsPerSample() / 8),
+            channels=self.detector.NumChannels(),
+            rate=self.detector.SampleRate(),
+            frames_per_buffer=2048,
+            stream_callback=audio_callback)
+
+    def match_ticks(self,aticks):
+        tticks = self.trigger_ticks
+        """ locate the trigger position """
+        silence_before = 0
+        silence_after = 0
+        voice_after = 0
+        voice_before = 0
+        kw_passed = False
+        """ Pattern to match is: Silence - Voice - Detection - Voice* - Silence """
+        for _ans in reversed(aticks):
+            if kw_passed == True:
+                """ Before the keyword """
+                if _ans == -2:
+                    if voice_before == 0:
+                        """ fail - no voice before detection?! """
+                        logger.info("No match - no voice before hotword")
+                        return -1
+
+                    silence_before += 1
+                    if silence_before >= tticks[0]:
+                        """ break - complete """
+                        break
+
+                elif _ans == 0:
+                    """ voice """
+                    if silence_before>0:
+                        break
+                    voice_before += 1
+
+            else:
+                """ After the keyword """
+                if _ans > 0:
+                    """ found the keyword - switch to before keyword """
+                    kw_passed = True
+                    continue
+                if _ans == -2:
+                    """ silence """
+                    if voice_after == 0:
+                        """ silence after detection """
+                        silence_after += 1
+                    else:
+                        """ fail - voice between silence """
+                        logger.info("No match - after hotword, mix of silence and voice")
+                        return -1
+                elif _ans == 0:
+                    """ voice """
+                    voice_after += 1
+
+        logger.info("Ticks status: " + `silence_before` + " " +
+                `voice_before` + " " +
+                `voice_after` + " " + `silence_after`)
+
+        """ Match? """
+        if tticks[0]>0 and silence_before < tticks[0]:
+            """ will never match """
+            logger.info( "No match silence_before" )
+            return -1
+        if tticks[1]>0 and voice_before > tticks[1]:
+            """ will never match """
+            logger.info( "No match voice_before" )
+            return -1
+        if tticks[2]>0 and voice_after > tticks[2]:
+            """ will never match """
+            logger.info( "No match voice_after" )
+            return -1
+        if tticks[3]>0 and silence_after < tticks[3]:
+            """ can still match on next tick """
+            logger.info( "No match silence_after - wait next tick" )
+            return 0
+        """ A match ! """
+        return 1
+
+    def start(self, detected_callback=snowboydecoder.play_audio_file,
+              interrupt_check=lambda: False,
+              sleep_time=0.03):
+        """
+        Start the voice detector. For every `sleep_time` second it checks the
+        audio buffer for triggering keywords. If detected, then call
+        corresponding function in `detected_callback`, which can be a single
+        function (single model) or a list of callback functions (multiple
+        models). Every loop it also calls `interrupt_check` -- if it returns
+        True, then breaks from the loop and return.
+
+        :param detected_callback: a function or list of functions. The number of
+                                  items must match the number of models in
+                                  `decoder_model`.
+        :param interrupt_check: a function that returns True if the main loop
+                                needs to stop.
+        :param float sleep_time: how much time in second every loop waits.
+        :return: None
+        """
+        if interrupt_check():
+            logger.debug("detect voice return")
+            return
+
+        tc = type(detected_callback)
+        if tc is not list:
+            detected_callback = [detected_callback]
+        if len(detected_callback) == 1 and self.num_hotwords > 1:
+            detected_callback *= self.num_hotwords
+
+        assert self.num_hotwords == len(detected_callback), \
+            "Error: hotwords in your models (%d) do not match the number of " \
+            "callbacks (%d)" % (self.num_hotwords, len(detected_callback))
+
+        logger.debug("detecting...")
+
+        """ with ticks compute """
+        tticks = self.trigger_ticks
+        aticks = collections.deque()
+        w_ticks = False
+        w_ticks_onsilence = False
+        if tticks[2] != -1 or tticks[3] != -1:
+            w_ticks_onsilence = True
+        if tticks[0] != -1 or tticks[1] != -1 or w_ticks_onsilence != False:
+            w_ticks = True
+        callback = None
+
+        while True:
+            if interrupt_check():
+                logger.debug("detect voice break")
+                break
+
+            data = self.ring_buffer.get()
+            if len(data) == 0:
+                time.sleep(sleep_time)
+                continue
+
+            ans = self.detector.RunDetection(data)
+            check_ticks = False
+
+            """ with ticks: append and keep it under 100 ticks """
+            if w_ticks:
+                aticks.append( ans )
+                if len(aticks)>100:
+                    aticks.popleft()
+
+            if ans == -1:
+                logger.warning("Error initializing streams or reading audio data")
+
+            elif ans == -2:
+                """ silence can trigger the callback if w_ticks and matches """
+                if w_ticks_onsilence == False or callback is None:
+                    continue
+                check_ticks = True
+
+            elif ans > 0:
+                message = "Keyword " + str(ans) + " detected at time: "
+                message += time.strftime("%Y-%m-%d %H:%M:%S",
+                                         time.localtime(time.time()))
+                logger.info(message)
+                callback = detected_callback[ans-1]
+                if callback is not None:
+                    if w_ticks == False:
+                        callback()
+                    elif w_ticks_onsilence == False:
+                        check_ticks = True
+
+            if check_ticks:
+                ret = self.match_ticks( aticks )
+                if ret == -1:
+                    """ Not a match """
+                    callback = None
+                elif ret == 1:
+                    logger.warning("Callback run");
+                    callback()
+                    callback = None
+                """ ret == 0 : Not a match yet """
+
+        logger.debug("finished.")
+
+    def terminate(self):
+        """
+        Terminate audio stream. Users cannot call start() again to detect.
+        :return: None
+        """
+        self.stream_in.stop_stream()
+        self.stream_in.close()
+        self.audio.terminate()