Qt中Qchart插件实现PMW3901迷你光流模块上位机

光流计介绍

首先PMW3901 是一款迷你光流模块具有一下特点：

• 体积小、重量轻 仅0.6g
• 精度高
• 价格便宜
• 串口通信

PMW3901淘宝一搜一大片。串口通信协议如下图：

上位机

上位机使用Qt中的Qchart插件实现，实时显示X轴和Y轴速度变化量和X轴Y轴位移（这是在调试飞机时添加的，可以用软件里一个宏USE_UAV设置）。可以直观的看出速度的变化，方便调试。主界面如下:

Qchart使用方便一下代码是在窗口构造函数中添加的创建chart和坐标轴的函数：

 	m_chart = new QChart();
    QChartView *chartView = new QChartView(m_chart);
    chartView->setMinimumSize(800, 600);
    m_chart->addSeries(m_seriesX); //一共添加四条曲线
    m_chart->addSeries(m_seriesY);
    m_chart->addSeries(m_distX);
    m_chart->addSeries(m_distY);

    axisX = new QValueAxis; //设置图标坐标和文字等
    axisX->setRange(0, index_max);
    axisX->setLabelFormat("%g");
    axisX->setTitleText("sample");

    axisY = new QValueAxis;
    axisY->setRange(-indexY_range, indexY_range);
    axisY->setTitleText("speed");

    axis2Y = new QValueAxis();
    axis2Y->setRange(-50,50);
    axis2Y->setLabelFormat("%g");
    axis2Y->setTitleText("distance");

    axisY->setTickCount(11);  //设置Y轴上的网格数，11代表10个空格
    m_chart->setAxisX(axisX,m_seriesX);
    m_chart->setAxisY(axisY,m_seriesX);
    m_chart->setAxisX(axisX,m_seriesY);
    m_chart->setAxisY(axisY,m_seriesY);
    m_chart->addAxis(axis2Y,Qt::AlignRight);
    m_chart->setAxisY(axis2Y,m_distX);
    m_chart->setAxisY(axis2Y,m_distY);
    m_chart->setAxisX(axisX,m_distX);
    m_chart->setAxisX(axisX,m_distY);

    m_chart->legend()->setVisible(true);
    m_chart->legend()->setAlignment(Qt::AlignBottom);
    m_chart->setTitle("Optcial Flow Data");

然后在串口接收函数里更新chart：

/*串口数据接收处理槽函数*/
void Widget::SerialReceive()
{
    requestData = serial->readAll();
    uint8_t head,tail,sum;
#define USE_UAV 0  //通过无人机发数据还是直接用光流计

#if USE_UAV
    head = requestData[0];
    tail = requestData[12];
    flow_sum  = requestData[10];

    count++;  /*统计帧率*/

    if(index_x>index_max)
    {
        index_x=0;
        m_seriesX->clear();
        m_distX->clear();
    }
    if(index_y>index_max)
    {
        index_y=0;
        m_seriesY->clear();
        m_distY->clear();
    }
    if(head == 0xFE && tail ==0xAA) //根据协议解包
    {
        sum = requestData[2]+requestData[3]+requestData[4]+requestData[5]
                +requestData[6]+requestData[7]+requestData[8]+requestData[9];
        if(sum == flow_sum)
        {
            flow_SQUAL = requestData[11];

            dist_x = (int16_t)(requestData[2]<<8 | requestData[3]);
            dist_y = (int16_t)(requestData[4]<<8 | requestData[5]);
            flow_x = (int16_t)(requestData[6]<<8 | requestData[7]);
            flow_y = (int16_t)(requestData[8]<<8 | requestData[9]);
            m_seriesX->append(index_x,flow_x); //在曲线最末端追加一个点
            m_seriesY->append(index_y,flow_y);
            m_distX->append(index_x,dist_x);
            m_distY->append(index_y,dist_y);
            index_x++;
            index_y++;
            sum_data++;
            sum_label->setNum(sum_data);

        }
    }
    // qDebug()<<"head:"<<head<<"tail:"<<tail<<"sum:"<<sum<<"SQUAL:"<<SQUAL;
    // qDebug()<<"head:"<<head<<"tail:"<<tail<<"flow_sum:"<<flow_sum<<"sum:"<<sum;
     qDebug()<<"head:"<<head<<"tail:"<<tail<<"flow_x:"<<flow_x<<"flow_y:"<<flow_y;
#else
    head = requestData[0];
    tail = requestData[8];
    flow_sum  = requestData[6];

    count++;  /*统计帧率*/

    if(index_x>index_max)
    {
        index_x=0;
        m_seriesX->clear();
    }
    if(index_y>index_max)
    {
        index_y=0;
        m_seriesY->clear();
    }
    if(head == 0xFE && tail ==0xAA)
    {
        sum = requestData[2]+requestData[3]+requestData[4]+requestData[5];

        if(sum == flow_sum)
        {
            flow_SQUAL = requestData[7];
            flow_x = (int16_t)(requestData[3]<<8 | requestData[2]);
            flow_y = (int16_t)(requestData[5]<<8 | requestData[4]);
            m_seriesX->append(index_x++,flow_x); 
            m_seriesY->append(index_y++,flow_y);
            sum_data++;
            sum_label->setNum(sum_data);

        }
    }
    // qDebug()<<"head:"<<head<<"tail:"<<tail<<"sum:"<<sum<<"SQUAL:"<<SQUAL;
    // qDebug()<<"head:"<<head<<"tail:"<<tail<<"flow_sum:"<<flow_sum<<"sum:"<<sum;
     qDebug()<<"head:"<<head<<"tail:"<<tail<<"flow_x:"<<flow_x<<"flow_y:"<<flow_y;
#endif

}

完整工程猛戳这儿。