#include <SoftwareSerial.h>

/*
  Software serial multple serial test
 
 Receives from the hardware serial, sends to software serial.
 Receives from software serial, sends to hardware serial.
 
 The circuit: 
 * RX is digital pin 2 (connect to TX of other device)
 * TX is digital pin 3 (connect to RX of other device)
 
 created back in the mists of time
 modified 9 Apr 2012
 by Tom Igoe
 based on Mikal Hart's example
 
 This example code is in the public domain.
 
 */

SoftwareSerial mySerial(0, 1); // TX, RX
//int counter;
uint8_t blue_led = 2, green_led = 3, red_led = 7;
int temp_offset = 280, temperature;//, min_temp = 20, max_temp = 30, pwm;
int us_delay;

void setup()  
{
    // set the data rate for the SoftwareSerial port
    mySerial.begin(9600);
  
    ADCSRA |= 0b10000000;
    //delay(1); // << this makes ADC saturate at 1023
    pinMode(red_led, OUTPUT);
    pinMode(green_led, OUTPUT);
    pinMode(blue_led, OUTPUT);
}

void loop() // run over and over
{
    temperature = readTemp();
    mySerial.print(millis());
    mySerial.print(",");
    //mySerial.print("temp: ");
    mySerial.print(temperature);
    mySerial.print(",");
    //mySerial.print(" delay: ");
    mySerial.println(us_delay);

    us_delay = (temperature-20)*127/(120-28)+us_delay/2;
    if (us_delay > 255) us_delay = 255;
    else if (us_delay < 0) us_delay = 0;
    
    analogWrite(red_led, 255-us_delay);
    analogWrite(green_led, 255);
    analogWrite(blue_led, 255);
}

int readTemp() { 
  // Read temperature sensor against 1.1V reference
    ADMUX = _BV(REFS1) | _BV(MUX5) | _BV(MUX1);

    delay(2); // Wait for ADMUX setting to settle
    ADCSRA |= _BV(ADSC); // Start conversion
    while (bit_is_set(ADCSRA,ADSC)); // measuring

    uint8_t low = ADCL; // must read ADCL first - it then locks ADCH
    uint8_t high = ADCH; // unlocks both
    int result = (high << 8) | low; // combine the two

    return result-temp_offset;
}