// Reads temperature from TMP36 sensor (from SparkFun electronics) on Arduino Pro Mini 3.3V 8MHz
// Reports the readings to serial port
// Plug Vcc of sensor to digital 12
// Plug Gnd of sensor to gnd of the board
// Plug Vout of sensor to analog 0
// Monitoring diode (digital 13) blinks while sensor is being read
const int power = 12;
const int monitor = 13;
const int analog = A0;
const int serialRate = 9600 * 4;

void setup() {
  // Beware: This is for Arduino Pro Mini 8MHz
  // most boards do not need this division
  Serial.begin(serialRate / 2);
  pinMode(power, OUTPUT);
}

void loop() {
  // Power up the thermo sensor
  digitalWrite(power, HIGH);
  // Power up monitor led
  digitalWrite(monitor, HIGH);
  // Wait for consistent ADC reading
  delay(150);
  // Read sensor value
  int value = analogRead(analog);
  digitalWrite(power, LOW);
  digitalWrite(monitor, LOW);

  // Print values to serial
  // Formula is 10mV per degree celsius for this sensor
  // Arduino reference is 3.3 on this board
  // ADC range is 0 to 1023 (10 bits)
  Serial.println(100 * value * (3.3 / 1023));
  // Flush serial to get more consistent decoding at the other end of serial link
  Serial.flush();
  
  // Wait for next loop
  delay(2000);
}