English Pronunciation Training Machine

I made a pronunciation training machine using Google Speech API, because it is difficult for the Japanese to distinguish "L" and "R" pronunciations.

Overview

If you talk to the USB microphone connected to the Raspberry Pi by speaking to "right" or "light" and recognize it correctly, the servo motor points to the right when "right," and the LED lights if it is "light".

I use the Google Speech API to recognize the voice input to the microphone. I registered the API and got the key.

Raspberry Pi Settings

Install voice processing library sox.

$ sudo apt-get install alsa-utils sox libsox-fmt-all 

Python Program

When recording, light the red LED. When it recognizes "right" and "light" it sends a signal to Arduino (GPIO).

#!/usr/bin/env python
# -*- coding: utf-8 -*-
import requests
import json
import os
import commands
import time
import RPi.GPIO as GPIO
GOOGLE_APIKEY = 'Google Speech API key'
LISTEN_SECONDS = 3 #3 seconds recording
VOICE_IN_PATH = '/home/pi/tmp.flac'
#GPIO settings
GPIO.setmode(GPIO.BCM)
GPIO.setup(2, GPIO.OUT)
GPIO.setup(3, GPIO.OUT)
GPIO.setup(4, GPIO.OUT)
GPIO.output(2, 0)
GPIO.output(3, 0)
GPIO.output(4, 0)
#Audio input (voice -> sound data) 
def listen(seconds):
    print 'lestening...'
    cmdline = 'AUDIODEV=hw:1 rec -c 1 -r 17000 ' + VOICE_IN_PATH + \
        ' trim 0 ' + str(seconds)
    os.system(cmdline)
    return os.path.getsize(VOICE_IN_PATH)
#Voice recognition  (sound data -> text)
def recognize():
    print('recognizing...')  
    f = open(VOICE_IN_PATH, 'rb')
    voice = f.read()
    f.close()
    #English lang=en-US
    url = 'https://www.google.com/speech-api/v2/recognize?xjerr=1&client=chromium&'\
        'lang=en-US&maxresults=10&pfilter=0&xjerr=1&key=' + GOOGLE_APIKEY
    hds = {'Content-type': 'audio/x-flac; rate=17000'}
    try:  
        reply = requests.post(url, data=voice, headers=hds).text
    except IOError: 
        return '#CONN_ERR'
    except:
        return '#ERROR'
    objs = reply.split(os.linesep)
    for obj in objs:
        if not obj:
            continue
        alternatives = json.loads(obj)['result']
        if len(alternatives) == 0:
            continue
        return alternatives[0]['alternative'][0]['transcript']
    return ""
def current_milli_time():
    return int(round(time.time() * 1000))
if __name__ == '__main__':
    #first time record will be failed. 
    listen(1)
    no_word = 0
    wifi_err = 0
try:
    while True:
        #Audio input
        t0 = current_milli_time()
        GPIO.output(2, 1)  #Rec LED on
        size = listen(LISTEN_SECONDS)
        GPIO.output(2, 0)  #Rec LED off
        t = current_milli_time() - t0
        if (t < 2000):
            print 'USB microphone not available'
            time.sleep(10)
            continue
        print 'listened:' + str(t) + 'ms'
        print 'voice data size=' + str(size)  
        #Voice recognition
        t0 = current_milli_time()
        message = recognize().encode('utf-8')
        print 'recognized:' + str(current_milli_time() - t0) + 'ms'
        if (message == '#CONN_ERR'):
            print 'internet not available'  
            time.sleep(10)
            continue
        elif (message == '#ERROR'):
            print 'voice recognize failed' 
            time.sleep(10)
            continue
        print 'Result: ' + message
        #Discrimination Discrimination between "right" and "light" 
        if 'right' in message:
            print 'right'
            GPIO.output(3, 1)  #Servo turns the right
            GPIO.output(4, 0)  #Neopixel LED off
            time.sleep(3)
        elif 'light' in message:
            print 'light'
            GPIO.output(3, 0)  #Servo turns to the　orignal
            GPIO.output(4, 1)  #Neopixel LED on
            time.sleep(3)
        else:
            print 'non'
except KeyboardInterrupt:
    GPIO.cleanup()
    pass

Arduino IDE Program

The library for NeoPixel is below.

https://github.com/adafruit/Adafruit_NeoPixel

Code to receive the signal from the Raspberry Pi and control the servo and the NeoPixel ring.

#include <Servo.h> 
#include <Adafruit_NeoPixel.h>
int GPIO3 = 3; 
int GPIO4 = 4; 
int servo, LED; 
Servo myservo; 
Adafruit_NeoPixel strip = Adafruit_NeoPixel(12, 6, NEO_GRB + NEO_KHZ800); 
void setup() { 
 Serial.begin(9600); 
 // make the pushbutton's pin an input: 
 pinMode(GPIO3, INPUT); 
 pinMode(GPIO4, INPUT); 
 myservo.attach(9); 
 myservo.write(0); 
 myservo.detach(); 
 strip.begin(); 
 strip.show(); // Initialize all pixels to 'off' 
} 
void loop() { 
 //Read GPIO 
 servo = digitalRead(GPIO3); 
 LED = digitalRead(GPIO4); 
 Serial.print(servo); Serial.print("\t"); 
 Serial.println(LED); 
 //Servo 
 myservo.attach(9); 
 delay(100); 
 if(servo == 1){ 
   myservo.write(0); 
 }else{ 
   myservo.write(90); 
 } 
 myservo.detach(); 
 delay(100); 
 //LED 
 int bright = 20; 
 if(LED == 1){ 
   for(uint16_t i=0; i<strip.numPixels(); i++) { 
     strip.setPixelColor(i, strip.Color(bright, bright, bright)); 
   } 
   strip.show(); 
 }else{ 
   strip.clear(); 
   strip.show(); 
 } 
} 

Operation