sensors script

#!/usr/bin/env python
#
# GrovePi Project for smart library.
#	*	Reads the data from light, temperature and humidity, sound and ultrasonic range sensors
#	*	Sensor Connections on the GrovePi:
#
#			-> Grove light sensor		- Port A0
#			-> Grove DHT sensors		- Port D7
#			-> Grove sound sensor		- Port A1
#			-> Grove distance sensor	- Port D8
#			-> Grove LED			- Port D5
#
# NOTE:
#
# The GrovePi connects the Raspberry Pi and Grove sensors.  You can learn more about GrovePi here:  http://www.dexterindustries.com/GrovePi
#
# Have a question?  Ask on the forums here:  http://forum.dexterindustries.com/c/grovepi
#
'''
## License

The MIT License (MIT)

GrovePi for the Raspberry Pi: an open source platform for connecting Grove Sensors to the Raspberry Pi.
Copyright (C) 2015  Dexter Industries

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.
'''

import time
import grovepi
import subprocess
import math

print("System Working")


#analog sensor port number
light_sensor = 2

#digital sensor
temp_humidity_sensor = 7

#temp_humidity_sensor type
#	grove starter kit comes with the bluew sensor
blue=0
white=1

#ultrasonic sensor for distance
ultrasonic_ranger = 8

# Connect the Grove Sound Sensor to analog port A1
#sound_sensor = 1

# PIN modes
grovepi.pinMode(1,"INPUT")
grovepi.pinMode(8,"INPUT")
grovepi.pinMode(temp_humidity_sensor,"INPUT")
grovepi.pinMode(light_sensor,"INPUT")

# The threshold to turn the led on depending on sound 400.00 * 5 / 1024 = 1.95v
#threshold_value = 350


#############
#test timings
time_for_sensor	= 2		#  1 seconds


time_to_sleep		= 1
log_file="log_file.csv"

#Read the data from the sensors
def read_sensor():
	try:
		light=grovepi.analogRead(light_sensor)
		distance = grovepi.ultrasonicRead(ultrasonic_ranger)
		[temp,humidity] = grovepi.dht(temp_humidity_sensor,blue)
		#Return -1 in case of bad temp/humidity sensor reading
		if math.isnan(temp) or math.isnan(humidity):		#temp/humidity sensor sometimes gives nan
			return [-1,-1,-1,-1]
			temp = -1;
			humidity = -1;
		#sound = grovepi.analogRead(sound_sensor)
		return [light,temp,humidity,distance]

	#Return -1 in case of sensor error
	except IOError as TypeError:
			return [-1,-1,-1,-1]


#Save the initial time, we will use this to find out when it is time to take a picture or save a reading
last_read_sensor= int(time.time())

while True:
  try:
	curr_time_sec=int(time.time())

	# If it is time to take the sensor reading
	if curr_time_sec-last_read_sensor>time_for_sensor:
		[light,temp,humidity,distance]=read_sensor()
		# If any reading is a bad reading, skip the loop and try again
		if light==-1 or temp==-1 or humidity ==-1 or distance==-1:
			print("Bad reading of one of the sensors")
			#time.sleep(time_to_sleep)
			continue
		curr_time = time.strftime("%Y-%m-%d:%H-%M-%S")
		print(("Time:%s\nLight: %d\nTemp: %.2f\nHumidity:%.2f\nDistance: %d\n" %(curr_time,light,temp,humidity,distance)))

		#Update the last read time
		last_read_sensor=curr_time_sec


	#Slow down the loop
	time.sleep(time_to_sleep)
  except IOError:
	print ("Error")