在 python 中快速绘制数据

2022-01-18 00:00:00 python matplotlib plot arduino serial-port

问题描述

我正在尝试使用 arduino 绘制来自 mpu6050 imu 的数据.MPU6050 发送数据的速度比绘图快.Arduino 代码从串口提供 6 个数据，分别是 yaw、pitch、roll、ax、ay 和 az.我需要快速剧情的建议.

I'm trying to plot data from mpu6050 imu with arduino. MPU6050 sends data faster than plot. Arduino code gives 6 data which are yaw, pitch, roll, ax,ay and az from serial port. I need suggestions for fast plot .

Python 代码:

import serial
import matplotlib.pyplot as plt #import matplotlib library
from drawnow import * 

ser = serial.Serial('COM9', 115200)
yaw = 0.0
pitch =0.0
roll =0.0
ax =0.0
ay =0.0
az =0.0
o_yaw= [0]
o_pitch= [0]
o_roll= [0]
o_ax= [0]
o_ay= [0]
o_az= [0]
plt.ion()
cnt=0
def makeFig(): 
    plt.ylim(-1000,1000)                                 
    plt.grid(True)
    plt.ylabel('Magnitude')  
    plt.plot(olculen_ax, 'ro-', label='ax') 
    plt.plot(olculen_ay, 'bo-', label='ay')  
    plt.plot(olculen_az, 'go-', label='az')                               
    plt.legend()                    
while True:
    incoming=ser.readline()
    if ("hand" in incoming):
        incoming=incoming.split(":")
        if len(incoming)==8:
            yaw = float(incoming[1])
            pitch = float(incoming[2])
            roll = float(incoming[3])
            ax = float(incoming[4])
            ay = float(incoming[5])
            az = float(incoming[6])
            print "Split works"
    else:
        print incoming
    o_ax.append(ax)                    
    o_ay.append(ay)    
    o_az.append(az)
    o_yaw.append(yaw)
    o_pitch.append(pitch)
    o_roll.append(roll)              

    drawnow(makeFig)                       
    plt.pause(.00001)                     
    cnt=cnt+1
    if(cnt>50):                            
        o_ax.pop(0)
        o_ay.pop(0)                     
        o_az.pop(0)

Arduino 代码(我只是添加循环.代码源自 这个):

Arduino Code (I just add loop. code derived from this):

void loop() {
    if (!dmpReady) return;
    while (!mpuInterrupt && fifoCount < packetSize) {
    }

    mpuInterrupt = false;
    mpuIntStatus = mpu.getIntStatus();

    fifoCount = mpu.getFIFOCount();

     if ((mpuIntStatus & 0x10) || fifoCount == 1024) {
    mpu.resetFIFO();
    //Serial.println(F("FIFO overflow!"));
} else if (mpuIntStatus & 0x02) {
    while (fifoCount < packetSize) fifoCount = mpu.getFIFOCount();
    mpu.getFIFOBytes(fifoBuffer, packetSize);
    fifoCount -= packetSize;
    mpu.dmpGetQuaternion(&q, fifoBuffer);
    mpu.dmpGetAccel(&aa, fifoBuffer);
    mpu.dmpGetGravity(&gravity, &q);
    mpu.dmpGetLinearAccel(&aaReal, &aa, &gravity);
    mpu.dmpGetLinearAccelInWorld(&aaWorld, &aaReal, &q);
    mpu.dmpGetYawPitchRoll(ypr, &q, &gravity);
    Serial.print("hand:");
    Serial.print(ypr[0] * 180/M_PI);
    Serial.print(":");
    Serial.print(ypr[1] * 180/M_PI);
    Serial.print(":");
    Serial.print(ypr[2] * 180/M_PI);
    Serial.print(":");
    Serial.print(aaWorld.x);
    Serial.print(":");
    Serial.print(aaWorld.y);
    Serial.print(":");
    Serial.print(aaWorld.z);
    Serial.println(":");
}

}

解决方案

pyqtgraph 模块是一个很好的解决方案.它非常快速和简单.

The pyqtgraph module is a great solution. It is very fast and easy.

这是新代码:

from pyqtgraph.Qt import QtGui, QtCore
import numpy as np
import pyqtgraph as pg
from pyqtgraph.ptime import time
import serial

app = QtGui.QApplication([])

p = pg.plot()
p.setWindowTitle('live plot from serial')
curve = p.plot()

data = [0]
raw=serial.Serial('COM9', 115200)


def update():
    global curve, data
    line = raw.readline()
    if ("hand" in line):
       line=line.split(":")
       if len(line)==8:
            data.append(float(line[4]))
            xdata = np.array(data, dtype='float64')
            curve.setData(xdata)
            app.processEvents()

timer = QtCore.QTimer()
timer.timeout.connect(update)
timer.start(0)

if __name__ == '__main__':
    import sys
    if (sys.flags.interactive != 1) or not hasattr(QtCore, 'PYQT_VERSION'):
        QtGui.QApplication.instance().exec_()

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