Finding Peak and Valley with 1st Derivative

    
Looks like need some threshold to eliminate small noise bug as the right photo...

 
       ...
      //Randomize the sample as input
      int v = (int)random(-40, 40);
      a+=0.2; A = (int) (80 + sin(a) * (v+50)); //add sine wave
   
      stroke(100, 100, 100);
      line(lastXPos, lastA,   xPos, A); //draw gray samples------------------------------------

      //smooth it
      B = smooth(A, 0.9, B);    
   
      //get 1st derivative
      C = B - lastB;                   //  f''(x) =  f(x) - f(x-1);
      C = (C + lastC) >> 1;        // some easy smooth
         
      stroke(250, 100, 100);
      line(lastXPos, 100+lastB,   xPos, 100+B);          //draw smoothed samples-------------
      line(lastXPos+1, 100+lastB,   xPos+1, 100+B);

      stroke(100, 100, 250);
      line(lastXPos, 400+(lastC*8),   xPos, 400+(C*8));//draw 1st derivatives  --------------
      if ((C*lastC) <= 0) {
        //f'(x) changed; when (f'(x)>0, f'(x-1)<0) or (f'(x)<0, f'(x-1)>0) or f'(x)=0 or f'x(x-1)=0    
        if (lastC >0)  {//found valley, draw line------
           stroke(40,40, 60);
           line(xPos, 400, xPos, 200);
           }
        if (lastC <0)  {//found peak, draw line-------
           stroke(80,80, 120);
           line(xPos, 400, xPos, 150);
           }
        }
 
      lastA = A;           //store current value for next iteration
      lastB = B;
      lastC = C;
   
      lastXPos = xPos; //move forward
      ...

Change random samples into Perlin noise

Low Pass Smoothing & DC Removal

Smoothing w/ Eric Forman

Smoothing w/ Tom Igoe

Smoothing w/ Paul Badger

Eric Forman: http://teaching.ericforman.com/smoothing-sensor-input/

Tom Igoe:     http://www.tigoe.com/pcomp/code/arduinowiring/41/

Paul Badger: http://playground.arduino.cc/main/smooth

SI1143 Heartbeat Pulse Evaluate

Arduino reading

SI1143 setup

Processing Arduino SI1143 red data (baud:57600, samples:10)

After the SI1143 carefully setup, the total red light (IR+visible) data send to Processing for drawing, looks like finger tip is the best monitor place...

Processing red data w/ HRV (baud:115200, samples:2)

Processing red data w/ HRV (baud:115200, samples:1)

Improved one read from 2.5ms to 0.9ms, w/ some beers... (samples:4)

SI1143 Evaluate:Ambient Light, Proximity, Temperature

As default setup,
LED current sunk: 0x01, ~10cm stable detection
LED current sunk: 0x0F, ~30cm+ stable detection



...
  write_reg(HW_KEY, 0x17); 
  //0x0F:30cm detection, 0x01:10cm dectection
  write_reg(PS_LED21,0xFF); 
  write_reg(PS_LED3, 0x0F); 
  //Enable AUX as well
  param_set(CHLIST,0b01010111);
...

Temperature reading on IO Shield OLED

Connect Max32 SDA and SCL pins(20 and 21) to pins A4 and A5 of  IO Shield. 

Hack Arduino Leonardo RX/TX LED

Use all LED on the Arduino Leonardo

int led = 13;

// the setup routine runs once when you press reset:
void setup() {                
  // initialize the digital pin as an output.
  pinMode(led, OUTPUT);       
  }

// the loop routine runs over and over again forever:
void loop() {
  digitalWrite(led, HIGH);   // turn the LED on (HIGH is the voltage level)
  RXLED1;
  TXLED1;
  delay(300);               // wait for a second
  
  digitalWrite(led, LOW);    // turn the LED off by making the voltage LOW
  RXLED0;
  TXLED0;
  delay(300);               // wait for a second
}