Hello, I'm currently trying the OYMotion Sensor.
The set up and everything seems all and good, and when I upload the sketch the Arduino IDE doesn't seem to find any errors on the coding. However I think the sensor seems to not able to detect the EMG?
Even when I'm not attaching the sensor to any body part, it still shows random numbers like below when it should've been 0.
And the sudden spike of 4 million showing is abnormal I think.
The code I used is below :
#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);
}
delay(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;
}
}
Thank you in advance!