MyoWare Muscle Sensor and Adafruit Feather 43u4

---

Ok, so I just wanted to look at this one. The guide is here: https://learn.adafruit.com/heybrows/overview .. It's under an MIT license for the code:

*********************************************************************
  This is an example for our nRF51822 based Bluefruit LE modules

  Pick one up today in the adafruit shop!

  Adafruit invests time and resources providing this open source code,
  please support Adafruit and open-source hardware by purchasing
  products from Adafruit!

  MIT license, check LICENSE for more information
  All text above, and the splash screen below must be included in
  any redistribution
*********************************************************************/

#include <Arduino.h>
#include <SPI.h>
#if not defined (_VARIANT_ARDUINO_DUE_X_) && not defined (_VARIANT_ARDUINO_ZERO_)
#include <SoftwareSerial.h>
#endif

#include "Adafruit_BLE.h"
#include "Adafruit_BluefruitLE_SPI.h"
#include "Adafruit_BluefruitLE_UART.h"

#include "BluefruitConfig.h"

/*=========================================================================
    APPLICATION SETTINGS

      FACTORYRESET_ENABLE       Perform a factory reset when running this sketch
     
                                Enabling this will put your Bluefruit LE module
                              in a 'known good' state and clear any config
                              data set in previous sketches or projects, so
                                running this at least once is a good idea.
     
                                When deploying your project, however, you will
                              want to disable factory reset by setting this
                              value to 0.  If you are making changes to your
                                Bluefruit LE device via AT commands, and those
                              changes aren't persisting across resets, this
                              is the reason why.  Factory reset will erase
                              the non-volatile memory where config data is
                              stored, setting it back to factory default
                              values.
         
                                Some sketches that require you to bond to a
                              central device (HID mouse, keyboard, etc.)
                              won't work at all with this feature enabled
                              since the factory reset will clear all of the
                              bonding data stored on the chip, meaning the
                              central device won't be able to reconnect.
    MINIMUM_FIRMWARE_VERSION  Minimum firmware version to have some new features
    MODE_LED_BEHAVIOUR        LED activity, valid options are
                              "DISABLE" or "MODE" or "BLEUART" or
                              "HWUART"  or "SPI"  or "MANUAL"
    -----------------------------------------------------------------------*/
#define FACTORYRESET_ENABLE         1
#define MINIMUM_FIRMWARE_VERSION    "0.6.6"
#define MODE_LED_BEHAVIOUR          "MODE"
/*=========================================================================*/

// Create the bluefruit object, either software serial...uncomment these lines
/*
  SoftwareSerial bluefruitSS = SoftwareSerial(BLUEFRUIT_SWUART_TXD_PIN, BLUEFRUIT_SWUART_RXD_PIN);

  Adafruit_BluefruitLE_UART ble(bluefruitSS, BLUEFRUIT_UART_MODE_PIN,
                      BLUEFRUIT_UART_CTS_PIN, BLUEFRUIT_UART_RTS_PIN);
*/

/* ...or hardware serial, which does not need the RTS/CTS pins. Uncomment this line */
//Adafruit_BluefruitLE_UART ble(BLUEFRUIT_HWSERIAL_NAME, BLUEFRUIT_UART_MODE_PIN);

/* ...hardware SPI, using SCK/MOSI/MISO hardware SPI pins and then user selected CS/IRQ/RST */
Adafruit_BluefruitLE_SPI ble(BLUEFRUIT_SPI_CS, BLUEFRUIT_SPI_IRQ, BLUEFRUIT_SPI_RST);

/* ...software SPI, using SCK/MOSI/MISO user-defined SPI pins and then user selected CS/IRQ/RST */
//Adafruit_BluefruitLE_SPI ble(BLUEFRUIT_SPI_SCK, BLUEFRUIT_SPI_MISO,
//                             BLUEFRUIT_SPI_MOSI, BLUEFRUIT_SPI_CS,
//                             BLUEFRUIT_SPI_IRQ, BLUEFRUIT_SPI_RST);


// A small helper
void error(const __FlashStringHelper*err) {
  Serial.println(err);
  while (1);
}

int threshold = 500;  //change this value to reflect the range of your muscle sensor
int oldSensorValue = 0;

/**************************************************************************/
/*!
    @brief  Sets up the HW an the BLE module (this function is called
            automatically on startup)
*/
/**************************************************************************/
void setup(void)
{
  //while (!Serial);  // required for Flora & Micro
  // delay(500);

  Serial.begin(115200);

  Serial.println("'Sup Brows!"); Serial.println("");

  /* We're ready to go! */
  Serial.println("");

  Serial.println(F("Adafruit Bluefruit Command <-> Data Mode communication"));
  Serial.println(F("------------------------------------------------"));

  /* Initialise the module */
  Serial.print(F("Initialising the Bluefruit LE module: "));

  if ( !ble.begin(VERBOSE_MODE) )
  {
    error(F("Couldn't find Bluefruit, make sure it's in CoMmanD mode & check wiring?"));
  }
  Serial.println( F("OK!") );

  if ( FACTORYRESET_ENABLE )
  {
    /* Perform a factory reset to make sure everything is in a known state */
    Serial.println(F("Performing a factory reset: "));
    if ( ! ble.factoryReset() ) {
      error(F("Couldn't factory reset"));
    }
  }

  /* Disable command echo from Bluefruit */
  ble.echo(false);

  Serial.println("Requesting Bluefruit info:");
  /* Print Bluefruit information */
  ble.info();

  Serial.println(F("Please use Adafruit Bluefruit LE app to connect in UART mode"));
  Serial.println();

  ble.verbose(false);  // debug info is a little annoying after this point!

  /* Wait for connection */
  while (! ble.isConnected()) {
    delay(500);
  }

  Serial.println(F("******************************"));

  // LED Activity command is only supported from 0.6.6
  if ( ble.isVersionAtLeast(MINIMUM_FIRMWARE_VERSION) )
  {
    // Change Mode LED Activity
    Serial.println(F("Change LED activity to " MODE_LED_BEHAVIOUR));
    ble.sendCommandCheckOK("AT+HWModeLED=" MODE_LED_BEHAVIOUR);
  }

  // Set module to DATA mode
  Serial.println( F("Switching to DATA mode!") );
  ble.setMode(BLUEFRUIT_MODE_DATA);

  Serial.println(F("******************************"));
}

/**************************************************************************/
/*!
    @brief  Constantly poll for new command or response data
*/
/**************************************************************************/
void loop(void)
{

  int sensorValue = analogRead(0);
  
  //Just stream sensor value
  ble.println(sensorValue);

  //Only send message when sensor value moves above threshold
/*
  if (sensorValue > threshold && oldSensorValue < threshold) {
    ble.println(sensorValue);
  }
  
  oldSensorValue = sensorValue;
  */
  delay(500);

}

 The includes are:

#include <arduino.h>
#include <spi.h>
#if not defined (_VARIANT_ARDUINO_DUE_X_) && not defined (_VARIANT_ARDUINO_ZERO_)
#include <softwareserial.h>
#endif

#include "Adafruit_BLE.h"
#include "Adafruit_BluefruitLE_SPI.h"
#include "Adafruit_BluefruitLE_UART.h"

#include "BluefruitConfig.h"
#include "softwareserial.h"
#include "spi.h"
#include "arduino.h

I dunno, the bluetooth stuff seems a bit more complicated than what I'm used to on Rasp Pi. So it'll take longer than I thought to complete this!

1. First connect MyoWare EMG sensor to Arduino:

MyoWare "+" to +ve on Arduino
MyoWare "-" to GND on Arduino
MyoWare "SIG" to analogue pin on Arduino

2. Code for printing what we get using the Arduino IDE serial monitor:

int analogValue = 0;    // variable to hold the analog value

void setup() {
  // open the serial port at 9600 bps:
  Serial.begin(9600);
}

void loop() {
  // read the analog input on pin 0:
  analogValue = analogRead(0);

  // print it out in many formats:
  Serial.println(analogValue);       // print as an ASCII-encoded decimal
  Serial.println(analogValue, DEC);  // print as an ASCII-encoded decimal
  Serial.println(analogValue, HEX);  // print as an ASCII-encoded hexadecimal
  Serial.println(analogValue, OCT);  // print as an ASCII-encoded octal
  Serial.println(analogValue, BIN);  // print as an ASCII-encoded binary
  delay(10)
}

Code from https://www.arduino.cc/en/Serial/Println

serial.begin is to set data rate in baud https://www.arduino.cc/en/Serial/Begin

analogRead(0) analogue read from A0 pin on Arduino - put this in analogValue

Then go ahead and print the analogValue to the serial monitor

Next just print it to serial monitor

Then we can use the serial plotter too! e.g. http://www.instructables.com/id/Ultimate-Guide-to-Adruino-Serial-Plotter/

Ah ok, so we should get data corresponding to open vs. closed fist from that.

Ok, so we want to get a  threshold value for closed fist. If it's above that we have closed fist, if it's below we don't have it.

Set const int closed_fist_threshold = whatever that value is

So then it's just   if(analogRead(0) > closed_fist_threshold: we have closed fist!

or else if (analogRead(0) < closed_fist_threshold: we don't have closed fist!

** this is all C++

----

It all seems very easy, but this threshold value will be the same for everyone? I think we will have to test this! I don't think it will be!  

const int closed_fist_threshold = ??? ///// threshold for closed fist. Anything 
//above is closed fist. Below is not closed fist

void setup() 
{ 
//start serial monitor, set data rate 9600 Baud
Serial.begin(9600); 
 

void loop() 
{ 
//print EMG data to serial monitor for debug
Serial.println(analogRead(0)); 

//if EMG data greater than threshold, we have a fist
  if(analogRead(0) > closed_fist_threshold) {
    //do something
  }

//if EMG data lower than threshold, we don't have a fist made
  else if (analogRead(0) < closed_fist_threshold) {
    //do something 
  }

}