反应本地中的polidea BLE解码特征值

如何解决反应本地中的polidea BLE解码特征值

我正在尝试解码从BLE接收到的软件包，但是我没有任何运气。如果您有任何想法，可以帮助我，我将不胜感激。这是我收到的base64示例：

ReadByte

我应该得到速度，电池电压，选项字节和odo

using System;
using System.IO;
using UnityEngine;

#if UNITY_WINRT && !UNITY_EDITOR
using Windows.Networking.Sockets;
using Windows.Networking;
using Windows.Networking.Connectivity;
using Windows.Storage.Streams;
using System.Runtime.InteropServices.WindowsRuntime;
#endif

public class NetworkManager : MonoBehaviour
{
    public int tcpPort;

#if UNITY_WINRT && !UNITY_EDITOR
    private StreamSocketListener streamSocketListener;
    private StreamReader tcpStreamReader = null;
    private StreamSocketListenerConnectionReceivedEventArgs connectionArgs;
    private DatagramSocket datagramSocket;
    private MemoryStream pendingDatagramSocketStream;
#endif

    private UInt32 tcpMessageSizeByteCount;
    private UInt32 tcpMessageSizeBytesRead;
    private byte[] tcpMessageSizeBuffer;

    private bool tcpMessageSizeReceived;

    private UInt32 tcpMessageByteCount;
    private UInt32 tcpMessageBytesRead;
    private byte[] tcpMessageBuffer;

    // Use this for initialization
    void Start()
    {
        Application.runInBackground = true;
        ResetTcpConnection();
    }

    public void ResetTcpConnection()
    {
#if UNITY_WINRT && !UNITY_EDITOR
        ResetTcpRead();

        if (streamSocketListener != null)
        {
            tcpStreamReader.Dispose();
            tcpStreamReader = null;
            connectionArgs = null;
            streamSocketListener.Dispose();
            streamSocketListener = null;
        }

        streamSocketListener = new StreamSocketListener();
        streamSocketListener.ConnectionReceived += this.StreamSocketListener_ConnectionReceived;
        streamSocketListener.BindServiceNameAsync(tcpPort.ToString());
#endif
    }

#if UNITY_WINRT && !UNITY_EDITOR
    // Process the client connection.
    private async void StreamSocketListener_ConnectionReceived(StreamSocketListener sender,StreamSocketListenerConnectionReceivedEventArgs args)
    {
        connectionArgs = args; // Keep this alive
        tcpStreamReader = new StreamReader(connectionArgs.Socket.InputStream.AsStreamForRead());
    }
#endif

    // Update is called once per frame
    void Update()
    {
#if UNITY_WINRT && !UNITY_EDITOR
        if (tcpStreamReader != null && !tcpStreamReader.EndOfStream)
        {
            Stream stream = tcpStreamReader.BaseStream;
            ReadTcpData(ref stream);
        }
#endif
    }

    private void ResetTcpRead()
    {
        tcpMessageSizeByteCount = sizeof(UInt32);
        tcpMessageSizeBytesRead = 0;
        tcpMessageSizeBuffer = new byte[tcpMessageSizeByteCount];

        tcpMessageSizeReceived = false;

        tcpMessageByteCount = 0;
        tcpMessageBytesRead = 0;
        tcpMessageBuffer = null;
    }

    private void ReadTcpData(ref Stream stream)
    {
        try
        {
            if (!tcpMessageSizeReceived)
            {
#if UNITY_WINRT && !UNITY_EDITOR
                while(tcpMessageSizeBytesRead < tcpMessageSizeByteCount && !tcpStreamReader.EndOfStream)
                {
                    tcpMessageSizeBuffer[tcpMessageSizeBytesRead++] = (byte)stream.ReadByte();
                }

                if(tcpMessageSizeBytesRead == tcpMessageSizeByteCount)
                {
                    tcpMessageByteCount = BitConverter.ToUInt32(tcpMessageSizeBuffer,0);
                }
#endif

                if (tcpMessageByteCount > 0)
                {
                    tcpMessageBuffer = new byte[tcpMessageByteCount];
                    tcpMessageSizeReceived = true;
                }
            }
            else
            {
                // Read the message
                int bytesToRead = (int)(tcpMessageByteCount - tcpMessageBytesRead);
                bytesToRead = bytesToRead > 10000 ? 10000 : bytesToRead;
                int bytesRead = stream.Read(tcpMessageBuffer,(int)tcpMessageBytesRead,bytesToRead);
                tcpMessageBytesRead += (uint)bytesRead;

                // Did we finish reading the message?
                if (tcpMessageBytesRead >= tcpMessageByteCount)
                {
                    ResetTcpRead();
                }
            }
        }
        catch (Exception e)
        {
            throw e;
        }
    }
}

解决方法

查看Polidea / react-native-ble-plx库，似乎从特征读取的数据返回了base64。因此，作为字节数组，您的值将是：

AcgAyQ== is [1,200,201]
Av0BAA== is [2,253,1,0]
A0IARQ== is [3,66,69]
BGQEbA== is [4,100,4,108]

这看起来像第一个字节是OpCode，最后一个字节是校验和。我会假设两者之间的字节是小端字节序中的值。

我尝试了一些代码：

import toUint8Array from 'urlb64touint8array';
import { Buffer } from 'buffer'

var speed_bytes = toUint8Array('AcgAyQ==');
var battery_bytes = toUint8Array('Av0BAA==');
var option_bytes = toUint8Array('A0IARQ==');
var odo_bytes = toUint8Array('BGQEbA==');

var speed = Buffer(speed_bytes).readInt16LE(1) / 10;
var battery = Buffer(battery_bytes).readInt16LE(1) / 10;
var options = (Buffer(option_bytes).readInt16LE(1) >>> 0).toString(2)
var odo = Buffer(odo_bytes).readInt16LE(1) / 10;

console.log('Processing speed: [' + speed_bytes + '] ' + speed);
console.log('Processing battery: [' + battery_bytes + '] ' + battery);
console.log('Processing option: [' + option_bytes + '] ' + options);
console.log('Processing odo: [' + odo_bytes + '] ' + odo);

哪个给出了以下输出：

Processing speed: [1,201] 20 
Processing battery: [2,0] 50.9 
Processing option: [3,69] 1000010 
Processing odo: [4,108] 112.4