_SKU_SEN0240_肌电传感器_Analog_EMG_Sensor_by_OYMotion - jimaobian/DFRobotWikiCn GitHub Wiki

/*
* Copyright 2017, OYMotion Inc.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
*    notice, this list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright
*    notice, this list of conditions and the following disclaimer in
*    the documentation and/or other materials provided with the
*    distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF
* THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
* DAMAGE.
*
*/

#if defined(ARDUINO) && ARDUINO >= 100
#include "Arduino.h"
#else
#include "WProgram.h"
#endif

#include "EMGFilters.h"

#define TIMING_DEBUG 1

#define SensorInputPin A0 // input pin number

EMGFilters myFilter;
// discrete filters must works with fixed sample frequence
// our emg filter only support "SAMPLE_FREQ_500HZ" or "SAMPLE_FREQ_1000HZ"
// other sampleRate inputs will bypass all the EMG_FILTER
int sampleRate = SAMPLE_FREQ_1000HZ;
// For countries where power transmission is at 50 Hz
// For countries where power transmission is at 60 Hz, need to change to
// "NOTCH_FREQ_60HZ"
// our emg filter only support 50Hz and 60Hz input
// other inputs will bypass all the EMG_FILTER
int humFreq = NOTCH_FREQ_50HZ;

// Calibration:
// put on the sensors, and release your muscles;
// wait a few seconds, and select the max value as the threshold;
// any value under threshold will be set to zero
static int Threshold = 0;

unsigned long timeStamp;
unsigned long timeBudget;

void setup() {
    /* add setup code here */
    myFilter.init(sampleRate, humFreq, true, true, true);

    // open serial
    Serial.begin(115200);

    // setup for time cost measure
    // using micros()
    timeBudget = 1e6 / sampleRate;
    // micros will overflow and auto return to zero every 70 minutes
}

void loop() {
    /* add main program code here */
    // In order to make sure the ADC sample frequence on arduino,
    // the time cost should be measured each loop
    /*------------start here-------------------*/
    timeStamp = micros();

    int Value = analogRead(SensorInputPin);

    // filter processing
    int DataAfterFilter = myFilter.update(Value);

    int envlope = sq(DataAfterFilter);
    // any value under threshold will be set to zero
    envlope = (envlope > Threshold) ? envlope : 0;

    timeStamp = micros() - timeStamp;
    if (TIMING_DEBUG) {
        // Serial.print("Read Data: "); Serial.println(Value);
        // Serial.print("Filtered Data: ");Serial.println(DataAfterFilter);
        Serial.print("Squared Data: ");
        Serial.println(envlope);
        // Serial.print("Filters cost time: "); Serial.println(timeStamp);
        // the filter cost average around 520 us
    }

    /*------------end here---------------------*/
    // if less than timeBudget, then you still have (timeBudget - timeStamp) to
    // do your work
    delayMicroseconds(500);
    // if more than timeBudget, the sample rate need to reduce to
    // SAMPLE_FREQ_500HZ
}

  -
    一般情况下，肌肉放松时，是一条值始终为0的直线，如下图所示。如偶尔有几个尖峰波形出现，也属正常现象。


![肌电信号_放松.png](http://imgtest.dfrobot.com.cn/DFRobotCnWikiImage/肌电信号_放松.png "肌电信号_放松.png")

  -
    用力握拳的过程中，可看到明显的肌电波形，如下图所示。


![肌电信号_握拳.png](http://imgtest.dfrobot.com.cn/DFRobotCnWikiImage/肌电信号_握拳.png "肌电信号_握拳.png")

/*
   Copyright 2017, OYMotion Inc.
   All rights reserved.

   Redistribution and use in source and binary forms, with or without
   modification, are permitted provided that the following conditions
   are met:
   1. Redistributions of source code must retain the above copyright
      notice, this list of conditions and the following disclaimer.
   2. Redistributions in binary form must reproduce the above copyright
      notice, this list of conditions and the following disclaimer in
      the documentation and/or other materials provided with the
      distribution.

   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
   "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
   FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
   COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
   INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
   BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
   OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
   AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
   OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF
   THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
   DAMAGE.
*/

#if defined(ARDUINO) && ARDUINO >= 100
#include "Arduino.h"
#else
#include "WProgram.h"
#endif

#include "EMGFilters.h"
#define SensorInputPin A0   //sensor input pin number

/*
  Define the `threshold` variable as 0 to calibrate the baseline value of input sEMG signals first.
  After wiring the sEMG sensors to the Arduino board, wear the sEMG sensors. Relax your muscles for a few seconds,
  you will be able to see a series of squared sEMG signals values get printed on your serial terminal.
  Choose the maximal one as the baseline by setting the `threshold` variable. Then rebuild this project.
  The `envelope`, which is the squared sEMG signal data, will be printed to the serial line.
  The developer can plot it using the Arduino SerialPlotter.

  Note:
      After calibration, Any squared value of sEMG sigal below the baseline will be treated as zero.
      It is recommended that you do calibration every time you wear the sEMG sensor.
*/
unsigned long threshold = 0;  // threshold: Relaxed baseline values.(threshold=0:in the calibration process)
unsigned long EMG_num = 0;      // EMG_num: The number of statistical signals

EMGFilters myFilter;
/*
  Set the input frequency.
  The filters work only with fixed sample frequency of
  `SAMPLE_FREQ_500HZ` or `SAMPLE_FREQ_1000HZ`.
  Inputs at other sample rates will bypass
*/
SAMPLE_FREQUENCY sampleRate = SAMPLE_FREQ_500HZ;
/*
  Set the frequency of power line hum to filter out.
  For countries with 60Hz power line, change to "NOTCH_FREQ_60HZ"
*/
NOTCH_FREQUENCY humFreq = NOTCH_FREQ_50HZ;

void setup()
{
  myFilter.init(sampleRate, humFreq, true, true, true);
  Serial.begin(115200);
}

void loop()
{
  int data = analogRead(SensorInputPin);
  int dataAfterFilter = myFilter.update(data);  // filter processing
  int envelope = sq(dataAfterFilter);   //Get envelope by squaring the input
  envelope = (envelope > threshold) ? envelope : 0;    // The data set below the base value is set to 0, indicating that it is in a relaxed state

  /* if threshold=0,explain the status it is in the calibration process,the code bollow not run.
     if get EMG singal,number++ and print
  */
  if (threshold > 0)
  {
    if (getEMGCount(envelope))
    {
      EMG_num++;
      Serial.print("EMG_num: ");
      Serial.println(EMG_num);
    }
  }
  else {
    Serial.println(envelope);
  }
  delayMicroseconds(500);
}

/*
   if get EMG signal,return 1;
*/
int getEMGCount(int gforce_envelope)
{
  static long integralData = 0;
  static long integralDataEve = 0;
  static bool remainFlag = false;
  static unsigned long timeMillis = 0;
  static unsigned long timeBeginzero = 0;
  static long fistNum = 0;
  static int  TimeStandard = 200;
  /*
    The integral is processed to continuously add the signal value
    and compare the integral value of the previous sampling to determine whether the signal is continuous
   */
  integralDataEve = integralData;
  integralData += gforce_envelope;
  /*
    If the integral is constant, and it doesn't equal 0, then the time is recorded;
    If the value of the integral starts to change again, the remainflag is true, and the time record will be re-entered next time
  */
  if ((integralDataEve == integralData) && (integralDataEve != 0))
  {
    timeMillis = millis();
    if (remainFlag)
    {
      timeBeginzero = timeMillis;
      remainFlag = false;
      return 0;
    }
    /* If the integral value exceeds 200 ms, the integral value is clear 0,return that get EMG signal */
    if ((timeMillis - timeBeginzero) > TimeStandard)
    {
      integralDataEve = integralData = 0;
      return 1;
    }
    return 0;
  }
  else {
    remainFlag = true;
    return 0;
   }
}

  -
    如发现松拳时，计数多次累加，则是阀值设置的较低，引起误判。可将代码中的threshold变量值再加100，重新上传样例代码至arduino主控板，再次查看效果，直到把threshold变量加到满意效果为止。

![握拳计数.png](http://imgtest.dfrobot.com.cn/DFRobotCnWikiImage/握拳计数.png "握拳计数.png")