import processing.serial.*;

Serial myPort;        // The serial port
int xPos = 1;         // horizontal position of the graph
float logTime=0;
boolean converting = false;
PrintWriter output;

void setup () {
// set the window size:
size(800, 400);        

// List all the available serial ports
println(Serial.list());
// I know that the first port in the serial list on my linux
// is always my Arduino, so I open Serial.list()[0].
// Open whatever port is the one you're using.
myPort = new Serial(this, Serial.list()[0], 115200);
// don't generate a serialEvent() unless you get a newline character:
myPort.bufferUntil('\n');
// set inital background:
background(0);
}
void draw () {
}

void keyTyped(){
  if((key == 's') && (!converting)) {
    output = createWriter("compression_" + str(hour()) + ":" + str(minute()) + ":" + str(second()) + ".msl");
    output.println ("DIY Rotary engine compression tester");
    output.println ("Time\tPressure");
    output.println ("s\tkg^cm2");
    xPos = 0;
    logTime=0;
    background (0);
    myPort.write ("s\n");
    converting = true;
  }
  if((key == 'p') && (converting)) {
    myPort.write ("p\n");
    output.flush();
    output.close();
    converting = false;
  }
}
void serialEvent (Serial myPort) {
// get the ASCII string:
String inString = myPort.readStringUntil('\n');
float voltage, pressure;

if (inString != null) {
// trim off any whitespace:
inString = trim(inString);
output.print(logTime);
logTime+=0.002; //bacause our arduino send values every 2ms.
output.print("\t");
float inByte = float(inString); //getting adc value (0-1023)
voltage = map(inByte, 0, 1023, 0, 5); //converting adc to voltage (0-5V)
pressure = map(voltage, 0.5, 4.5, 0, 10); //last two numbers is sensor pressure for 0.5 & 4.5V output
output.println(pressure);
inByte = map(inByte, 0, 1023, 0, height);
// draw the line:
stroke(127,34,255);
line(xPos, height, xPos, height - inByte);
xPos++; // increment the horizontal position:
// at the edge of the screen, go back to the beginning:
  if (xPos > width) {
   xPos = 0;
   background(0);
  }
}
}