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Currently I am trying to get a Mindwave Mobile device to operate with an Arduino Uno. I'm following the guide here.

However the sample code given doesn't work very well. I have been trying to get a more consistent output but to no avail.

MindWave Code :

#include <SoftwareSerial.h>     // library for software serial
SoftwareSerial mySerial(5, 6);  // RX, TX
int BAUDRATE = 57600;

// checksum variables
byte payloadChecksum = 0;
byte CalculatedChecksum;
byte checksum = 0;              //data type byte stores an 8-bit unsigned number, from 0 to 255
int payloadLength = 0;
byte payloadData[64] = {0};
byte poorQuality = 0;
byte attention = 0;
byte meditation = 0;

// system variables
long lastReceivedPacket = 0;
boolean bigPacket = false;
boolean brainwave = false;

void setup() {
  Serial.begin(57600);       // Bluetooth
  delay(500);
  mySerial.begin(4800);      // software serialz
  delay(500);
  Serial.print("Communicating... ");
  mySerial.print("Communicating... ");
  mySerial.println();
}

byte ReadOneByte() {
  int ByteRead;
  // Wait until there is data
  while (!Serial.available());
  //Get the number of bytes (characters) available for reading from the serial port.
  //This is data that's already arrived and stored in the serial receive buffer (which holds 64 bytes)
  ByteRead = Serial.read();
  return ByteRead; // read incoming serial data
}

unsigned int delta_wave = 0;
unsigned int theta_wave = 0;
unsigned int low_alpha_wave = 0;
unsigned int high_alpha_wave = 0;
unsigned int low_beta_wave = 0;
unsigned int high_beta_wave = 0;
unsigned int low_gamma_wave = 0;
unsigned int mid_gamma_wave = 0;

void read_waves(int i) {
  delta_wave = read_3byte_int(i);
  i += 3;
  theta_wave = read_3byte_int(i);
  i += 3;
  low_alpha_wave = read_3byte_int(i);
  i += 3;
  high_alpha_wave = read_3byte_int(i);
  i += 3;
  low_beta_wave = read_3byte_int(i);
  i += 3;
  high_beta_wave = read_3byte_int(i);
  i += 3;
  low_gamma_wave = read_3byte_int(i);
  i += 3;
  mid_gamma_wave = read_3byte_int(i);
}

int read_3byte_int(int i) {
  return ((payloadData[i] << 16) + (payloadData[i + 1] << 8) + payloadData[i + 2]);
}

void loop() {
  // Look for sync bytes
  // Byte order: 0xAA, 0xAA, payloadLength, payloadData,
  // Checksum (sum all the bytes of payload, take lowest 8 bits, then bit inverse on lowest
  if (ReadOneByte() == 0xAA) {
    if (ReadOneByte() == 0xAA) {
      payloadLength = ReadOneByte();
      if (payloadLength > 169) //Payload length can not be greater than 169
        return;
      payloadChecksum = 0;
      for (int i = 0; i < payloadLength; i++) {     //loop until payload length is complete
        payloadData[i] = ReadOneByte();             //Read payload
        payloadChecksum += payloadData[i];
      }
      checksum = ReadOneByte();                     //Read checksum byte from stream
      payloadChecksum = 255 - payloadChecksum;      //Take one’s compliment of generated checksum
      if (checksum == payloadChecksum) {
        poorQuality = 200;
        attention = 0;
        meditation = 0;
      }
      brainwave = false;
      for (int i = 0; i < payloadLength; i++) { // Parse the payload
        switch (payloadData[i]) {
          case 02:
            i++;
            poorQuality = payloadData[i];
            bigPacket = true;
            break;
          case 04:
            i++;
            attention = payloadData[i];
            break;
          case 05:
            i++;
            meditation = payloadData[i];
            break;
          case 0x80:
            i = i + 3;
            break;
          case 0x83:                         // ASIC EEG POWER INT
            i++;
            brainwave = true;
            byte vlen = payloadData[i];
            //mySerial.print(vlen, DEC);
            //mySerial.println();
            read_waves(i + 1);
            i += vlen; // i = i + vlen
            break;
        }                                 // switch
      }                                   // for loop

/*
      if (bigPacket) {
        if (poorQuality == 0) {
        }
        else {                            // do nothing
        }
      }
*/
      if (brainwave && attention > 0 && attention < 100) {
        mySerial.print(attention, DEC);
        mySerial.println();

        Serial.print(attention, DEC);
        Serial.println();
      }
    }
  }
}

Often, the serial monitor stops display new values that stems from the Mindwave. Any suggestions on how I could modify the code to get it to run more smoothly will be greatly appreciated.

1

No use in reinventing the wheel!

Brain is an Arduino Library for parsing data from Neurosky-based EEG headsets. Tested units include the Star Wars Force Trainer and Mattel MindFlex.

It's designed to make it simple to send out an ASCII string of comma-separated values over serial, or to access processed brain wave information directly in your Arduino sketch. See the examples for code demonstrating each use case.

https://github.com/kitschpatrol/Brain

Install the library, and set it up like this:

#include <Brain.h>

// Set up the brain parser, pass it the hardware serial object you want to listen on.
Brain brain(Serial);

void setup() {
// Start the hardware serial.
Serial.begin(9600);
}

void loop() {
// Expect packets about once per second.
// The .readCSV() function returns a string (well, char*) listing the most recent brain data, in the following format:
// "signal strength, attention, meditation, delta, theta, low alpha, high alpha, low beta, high beta, low gamma, high gamma"    
    if (brain.update()) {
    Serial.println(brain.readErrors());
    Serial.println(brain.readCSV());
    }
}

Can't guarantee that it will work, but if you have the TX pin of the bluetooth hooked up to the RX pin of the Arduino I'm pretty sure it will work.

0

I have just spotted this question because I had a similar issue: the while condition reading Serial data is blocking.

I've rewritten the parsing part a little bit, which you can see here.

This makes it smoother to run things in parallel, but it takes about the same time to accumulate a big packet of brainwave data.

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