一、什么是声波通讯

声波通信的原理其实比较简单，主要是用单频率声音信号对数据进行编码，然后播放这些单频率声音，接收方在收到声音后，识别出频率，然后根据频率解码出数据。比如：我们可以将1500HZ的正弦波对应数字1，1600HZ的正弦波对应数字2，1700HZ 的正弦波对应数字3。那么数字串3123就对应4段正弦波，规定每段正弦波持续100ms，则3123对应400毫秒的声音段。接收方录制声音，对收到的声音进行解析，识别出1700HZ，1500HZ，1600HZ，1700HZ四段正弦波频率，然后查找码本，解码出的数字就是3123。本文是参考https://blog.csdn.net/zhaokaiqiang1992/article/details/41149621开源Demo进行扩充。实现中英文字符传输

二、应用场景

支付宝声波支付、微信加好友、附近建群、基于超声波的电视/视频互动，基于超声波的电视/视频互动、歌曲识别，摇一摇；缺点也是相当明显，参考资料少，技术不开源，传输距离短，数据传输安全性低；

三、原理剖析

声波通讯.png

1.数据存储

package home.gz.com.sinvoicetool;

import java.util.concurrent.BlockingQueue;
import java.util.concurrent.LinkedBlockingDeque;

/**
 * @author Wudi
 * @date 2018/10/17
 * 数据的存储采用阻塞队列（BlockingQueue）
 */
public class SinBuffer {
    private final static String TAG = "SinBuffer";

    /**
     * 默认缓冲区大小 大于最100ms 内的采样率
     */
    public final static int DEFAULT_BUFFER_SIZE = 4096;
    /**
     * 默认缓冲区数量
     */
    public final static int DEFAULT_BUFFER_COUNT = 3;

    /**
     * 生产队列
     */
    private BlockingQueue<SinBufferData> sinBufferDataProducer;

    /**
     * 消费队列
     */
    private BlockingQueue<SinBufferData> sinBufferDataConsumer;

    // 静态空缓冲区
    private static SinBuffer.SinBufferData sEmptyBuffer = new SinBuffer.SinBufferData(0);

    public static SinBuffer.SinBufferData getsEmptyBuffer() {
        return sEmptyBuffer;
    }


    public SinBuffer() {
        this(DEFAULT_BUFFER_COUNT, DEFAULT_BUFFER_SIZE);
    }

    public SinBuffer(int mSinBufferCount, int mSinBufferSize) {
        sinBufferDataProducer = new LinkedBlockingDeque<>(mSinBufferCount);
        // 需要结束缓存，所以数量比生产者要+1
        sinBufferDataConsumer = new LinkedBlockingDeque<>(mSinBufferCount + 1);
        // 初始化生产者对立
        for (int i = 0; i < mSinBufferCount; i++) {
            try {
                sinBufferDataProducer.put(new SinBufferData(mSinBufferSize));
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        }
    }

    /**
     * 重置数据
     */
    public void resetSinBuffer() {
        // 将生产者的空头结点剔除
        int size = sinBufferDataProducer.size();
        for (int i = 0; i < size; i++) {
            SinBufferData sinBufferData = sinBufferDataProducer.peek();
            if (null == sinBufferData || null == sinBufferData.shortData) {
                sinBufferDataProducer.poll();
            }
        }
        // 将消费者中的非空数据添加到生产者当中
        size = sinBufferDataConsumer.size();
        for (int i = 0; i < size; i++) {
            SinBufferData sinBufferData = sinBufferDataConsumer.poll();
            if (null != sinBufferData && null != sinBufferData.shortData) {
                sinBufferDataProducer.add(sinBufferData);
            }
        }
    }

    /**
     * 获取生产者头节点
     */
    public SinBuffer.SinBufferData getFirstProducerNode() {
        return getBufferDataImpl(sinBufferDataProducer);
    }


    /**
     * 从消费者队列获取
     *
     * @return
     */
    public SinBuffer.SinBufferData getSinBufferConsumeData() {
        return getBufferDataImpl(sinBufferDataConsumer);
    }

    /**
     * 加入到消费者和队列
     * @param sinBufferData
     * @return
     */
    public boolean putSinBufferConsumeData(SinBufferData sinBufferData) {
        return putBufferDataImpl(sinBufferDataConsumer, sinBufferData);
    }

    /**
     * 写入数据到生产者队列
     *
     * @param sinBufferData
     * @return
     */
    public boolean putBufferData(SinBufferData sinBufferData) {
        return putBufferDataImpl(sinBufferDataProducer, sinBufferData);
    }

    /**
     * 读取缓存数据，FIFO
     *
     * @param dataBlockingQueue
     * @return
     */
    private SinBufferData getBufferDataImpl(BlockingQueue<SinBufferData> dataBlockingQueue) {
        if (dataBlockingQueue != null) {
            try {
                return dataBlockingQueue.take();
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        }
        return null;
    }

    /**
     * 写入缓存数据
     *
     * @param dataBlockingQueue
     * @param sinBufferData
     * @return
     */
    private boolean putBufferDataImpl(BlockingQueue<SinBufferData> dataBlockingQueue, SinBufferData sinBufferData) {
        if (dataBlockingQueue != null && sinBufferData != null) {
            try {
                dataBlockingQueue.put(sinBufferData);
                return true;
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        }
        return false;
    }

    public static class SinBufferData {
        /**
         * 数据存储采用16喂short
         */
        public byte[] shortData;
        /**
         * 填充体积大小
         */
        private int bufferSize;

        /**
         * 最大填充提及
         */
        private int maxBufferSize;

        /**
         * 静态的空缓冲区
         */
        public SinBufferData(int mMaxBufferSize) {
            this.maxBufferSize = mMaxBufferSize;
            bufferSize = 0;
            if (mMaxBufferSize > 0) {
                shortData = new byte[mMaxBufferSize];
            } else {
                shortData = null;
            }
        }

        public byte[] getShortData() {
            return shortData;
        }

        public void setShortData(byte[] shortData) {
            this.shortData = shortData;
        }

        public int getBufferSize() {
            return bufferSize;
        }

        public void setBufferSize(int bufferSize) {
            this.bufferSize = bufferSize;
        }

        public int getMaxBufferSize() {
            return maxBufferSize;
        }

        public void setMaxBufferSize(int maxBufferSize) {
            this.maxBufferSize = maxBufferSize;
            shortData = new byte[maxBufferSize];
        }

    }
}

2.通讯工具类

package home.gz.com.sinvoicetool;

import android.text.TextUtils;
import android.util.Log;

import java.util.ArrayList;
import java.util.List;

/**
 * @author Wudi
 * @date 2018/10/16
 */
public class CommonUtil {
    private static final String TAG = "CommonUtil";
    /**
     * ASCII 最小和最大字符限定
     */
    private final static int MIN_ASCII = 32, MAX_ASCII = 127;
    /**
     * 默认采样率
     */
    public final static int DEFAULT_SAMPLE_RATE = 44100;

    /**
     * 默认每个字发送的正弦波持续时间
     */
    public final static int DEFAULT_DURATION = 100;

    /**
     * 字符映射频率，采用二进制传输 8820代表符号间隔， 5512：代表1与开始标志  4409 ：代表0   3150 ：代表结束标志
     * 5  8  10  14
     */
    public static final int[] CODE_FREQUENCY = new int[]{8820, 5512, 4409, 3150};

    private static List<Integer> mCodes = new ArrayList<Integer>();

    /**
     * 将字符串转化为二进制流
     *
     * @param text
     * @return
     */
    public static List<Integer> convertStringToBit(String text) {
        // 存放二进制流
        mCodes.clear();
        if (!TextUtils.isEmpty(text)) {
            char[] chars = text.toCharArray();
            for (int i = 0; i < chars.length; i++) {
                addBitString(Integer.toBinaryString(chars[i]));
                mCodes.add(3);
                Log.d(TAG, String.valueOf(mCodes));
            }
        }
        return mCodes;
    }

    private static void addBitString(String bitString) {
        Log.d(TAG, "二进制编码：" + bitString);
        for (int j = 0; j < bitString.length(); j++) {
            if (bitString.charAt(j) == '1') {
                mCodes.add(1);
            } else {
                mCodes.add(2);
            }
            mCodes.add(0);
        }
    }


    /**
     * 将二进制转化为字符串
     *
     * @param bitStream
     * @return
     */
    public static String convertBitToString(String bitStream) {
        String text = "";
        if (!TextUtils.isEmpty(bitStream)) {
            Log.d(TAG, "二进制解码： " + bitStream);
            int[] temp = bitToIntArray(bitStream);
            int sum = 0;
            for (int i = 0; i < temp.length; i++) {
                sum += temp[temp.length - 1 - i] << i;
            }
            text = String.valueOf((char) sum);
        }
        return text;
    }

    /**
     * 将二进制字符串转换成int数组
     *
     * @param binStr
     * @return
     */
    public static int[] bitToIntArray(String binStr) {
        char[] temp = binStr.toCharArray();
        int[] result = new int[temp.length];
        for (int i = 0; i < temp.length; i++) {
            result[i] = temp[i] - 48;
        }
        return result;
    }

}

四、参考资料

声波通讯参考：
https://www.jianshu.com/p/56bfa1668568
https://blog.csdn.net/zhaokaiqiang1992/article/details/41149621
PCM数据参考：
https://www.cnblogs.com/TianFang/p/7894630.html
AudiotTrack与AudioRecord参考：
https://www.cnblogs.com/innost/archive/2011/01/09/1931457.html
https://www.cnblogs.com/renhui/p/7457321.html
二进制编码
https://www.jb51.net/article/114746.htm

声波通讯、配网、声波互动（一）