battery_monitor.py

#!/usr/bin/env python3
# Simple script to monitor battery status, CPU temperature and screen brightness.
# Opens file specified in filename and appends one line of data when the script 
# is run.
#
# Usage -
# 1) change the variable filename to whatever file you want to append your log to. 
# 2) make this script executable with chmod +x battery_monitor.py
# 3) append it to your crontab using crontab -e. My crontab entry looks like:
#    */1 * * * * /path/to/battery_monitor.py
#    This runs the script once every minute.
# Note: This script runs fine on my x230 laptop running archlinux. You most 
# definitely will have to tinker with it to get it running on yours.

import subprocess as sub
import re
from datetime import datetime

filename = '/path/to/log/file'


def parseSpaces(commandList):
    p = sub.Popen(commandList, stdout=sub.PIPE, stderr=sub.PIPE)
    output, errors = p.communicate()
    return re.split(' ', str(output))


def getBrightness():
    actual = '/sys/class/backlight/intel_backlight/actual_brightness'
    maxBrightness = '/sys/class/backlight/intel_backlight/max_brightness'
    ac = int(open(actual, 'r').read())
    maxb = int(open(maxBrightness, 'r').read())
    return int((ac*100)/maxb)

parsed = parseSpaces(['acpi', '-bi'])
if parsed[2][:-1] == 'Discharging':
    log = [str(datetime.now()),  # datetime
           parsed[2][:-1],  # chargingStatus
           parsed[3][:-1],  # charge remaiting
           parsed[4],  # time remaining
           parsed[14],  # list full charge
           parsed[17][:-3]]  # max capacity
else:
    log = [str(datetime.now()),  # datetime
           parsed[2][:-1],  # chargingStatus
           parsed[3][:-1],  # charge remaiting
           parsed[4],  # time remaining
           '-',  # list full charge
           '-']  # max capacity

parsed = parseSpaces(['acpi', '-t'])
log.append(parsed[3])  # CPU temperature

log.append(str(getBrightness()))  # backlight brightness

with open(filename, 'a') as fp:
    fp.write('\t'.join(log))
    fp.write('\n')