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#!/usr/bin/python3
# -*- coding: utf-8 -*-
"""Python script to read temperature from DS18B20.
I plug the sensor data into pin 4 on the raspberry pi which requires pin 4 to
be a gpio pin. If the modprobe commands don't results in the device showing up
in the bus folder then make sure the following line is in `/boot/config.txt`:
```
dtoverlay=w1-gpio,gpiopin=4
```
After rebooting and the script should work.
"""
import glob
import os
import time
def enable_kernel_modules():
"""Enable kernel modules."""
os.system('modprobe w1-gpio')
os.system('modprobe w1-therm')
def get_device_file():
"""Get the path to the the data file."""
base_dir = '/sys/bus/w1/devices/'
device_folder = glob.glob(base_dir + '28*')[0]
device_file = device_folder + '/w1_slave'
return device_file
def read_device_file(device_file):
"""Read the raw temperature from the device."""
f = open(device_file, 'r')
lines = f.readlines()
f.close()
return lines
def parse_raw_input(raw_input):
"""Parse raw data into temperatures."""
# Error reading, return nothing
if raw_input[0].strip()[-3:] != 'YES':
return None, None
equals_pos = raw_input[1].find('t=')
if equals_pos != -1:
temp_string = raw_input[1][equals_pos+2:]
temp_c = float(temp_string) / 1000.0
temp_f = temp_c * 9.0 / 5.0 + 32.0
return temp_c, temp_f
else:
return None, None
def main():
"""Main Function."""
enable_kernel_modules()
device_file = get_device_file()
while True:
raw_input = read_device_file(device_file)
print(parse_raw_input(raw_input))
if __name__ == '__main__':
"""Run main routine."""
main()
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