Raspberry Pi Data logging

Beer_Data_Logger.py

"""This program will be used to log data during the fermentation process.
The sensors will be hooked upto the raspberry pi and the data will be 
recorded to a .txt file on timed internals. It will record temperature
and light as of right now. Eventually this will also contorl a Peltier 
cooler and a fan. It will be installed on top of a fermentation chamber to 
maintain temperatures in acceptable yeast ranges. 

August 10, 2014 K. Snyder"""

#IMPORT MODULES
import datetime
import time
import os
import glob

#CREATE THE FILE/DIRECTORY FOR THE SENSOR
base_dir = '/sys/bus/w1/devices/'
device_folder = glob.glob(base_dir + '28*')[0]
device_file = device_folder + '/w1_slave'

'''THIS TAKES THE TIME DATA IN SECONDS AND CONVERTS IT INTO
YEAR MONTH DATE HOUR MINUTES SECOND'''
def timestamp():
	ts = time.time()
	st = datetime.datetime.fromtimestamp(ts).strftime('%Y-%m-%d %H:%M:%S')
	return st

#GLOBAL VARIABLES THAT ARE USED IN FUNCTIONS
record_rate = .5 #Measured in minutes

'''THIS CREATES A FILE BASED ON THE BEER NAME AND CREATES 
THE HEADER. THE USER CAN DEFINE IT AND IT WILL THEN CLOSE THE
DATA FILE. THE HEADERS ARE ALSO CREATED IN THIS SECTION INCLUIDNG
TIME      TEMPERATURE      LIGHT'''
def file_create():
	print 'Beer Data Logger Program version 0.1'
	print 'Creater: Kyle Snyder\n'
	file_name = raw_input("What beer type is this? ")
	file_list = [file_name,'.txt']
	f = open(''.join(file_list),'w')
	f.write(file_name + " " + timestamp() + '\n')
	f.write('TIME' + '\t' + 'TEMPERATURE' + '\t' + 'LUX\n')
	f.close()
	print 'Data file created...'
	print 'Data recording!!!'
	return ''.join(file_list)

#THIS FUNCTION WILL READ THE RAW DATA FROM THE SENSOR. IT WILL
#THEN BE CONVERTED TO MEANINFUL TEMPERATURE VALUES

def read_temp_raw():
    f = open(device_file, 'r')
    lines = f.readlines()
    f.close()
    return lines


#THIS ACTUALLY READS THE TEMP AND CONVERTS IT
def read_temp():
    lines = read_temp_raw()
    while lines[0].strip()[-3:] != 'YES':
        time.sleep(0.2)
        lines = read_temp_raw()
    equals_pos = lines[1].find('t=')
    if equals_pos != -1:
        temp_string = lines[1][equals_pos+2:]
        temp_c = float(temp_string) / 1000.0
        temp_f = temp_c * 9.0 / 5.0 + 32.0
        return "%.2f" % temp_f

#THIS WILL ACTUALLY RECORD THE DATA FROM THE SENSORS TO THE FILE
#IN TAB FORM.
def record_data(record_rate):
	start_time = time.time()
	while(True):
		new_time = time.time()
		if ((new_time-start_time)/60 > record_rate):
			f = open(file_name,'a')
			f.write(timestamp() + '\t' + str(read_temp()) + '\t' + '100' + '\n')
			f.close()
			print timestamp() + '\t' + str(read_temp()) + '\t' + '100'
			start_time = new_time


while True:
	file_name = file_create()
	record_data(record_rate)