Thanks for the comments, I made a few changes and I have it working the way I want now...
python code:
import serial
import time
ser = serial.Serial('/dev/ttyUSB0', 9600, timeout=1)
time.sleep(1)
logfile = open('test.csv', 'a')
while 1:
line = ser.readline()
now = time.strftime("%d/%m/%Y %H:%M:%S", time.localtime())
a = "%s, %s, %s" % (now, line, "\n")
print a
logfile.write(a)
logfile.flush()
logfile.close()
ser.close()
arduino code:
/* Sensor test sketch
for more information see http://www.ladyada.net/make/logshield/lighttemp.html
*/
#define aref_voltage 3.3 // we tie 3.3V to ARef and measure it with a multimeter!
//TMP36 Pin Variables
int tempPin = 1; //the analog pin the TMP36's Vout (sense) pin is connected to
//the resolution is 10 mV / degree centigrade with a
//500 mV offset to allow for negative temperatures
int tempReading; // the analog reading from the sensor
int led_state;
void setup(void) {
// We'll send debugging information via the Serial monitor
Serial.begin(9600);
pinMode(13, OUTPUT);
Serial.println("Ready");
// If you want to set the aref to something other than 5v
analogReference(EXTERNAL);
}
void loop(void) {
tempReading = analogRead(tempPin);
//Serial.print("Temp reading = ");
//Serial.print(tempReading); // the raw analog reading
// converting that reading to voltage, which is based off the reference voltage
float voltage = tempReading * aref_voltage;
voltage /= 1024.0;
// print out the voltage
//Serial.print(" - ");
//Serial.print(voltage); Serial.println(" volts");
//Serial.print(temperatureC); Serial.println(" degrees C");
// now print out the temperature
float temperatureC = (voltage - 0.5) * 100 ; //converting from 10 mv per degree wit 500 mV offset
//to degrees ((volatge - 500mV) times 100)
// now convert to Fahrenheight
float temperatureF = (temperatureC * 9.0 / 5.0) + 32.0;
Serial.print(temperatureF);
//Serial.print(",");
digitalWrite(13,led_state);
led_state=!led_state;
//Serial.println(" degrees F");
delay(2000);
}