Freelancing: Python script to monitor temperature sensors on Raspberry Pi
Making money as a full-time undergrad is no easy feat, and many computer science majors find freelance programming provides a complementary income to working a real job, and in some cases freelancing is a developers primary income. The issue most programmers face with freelancing is finding consistent work; so a few websites exist to gather people looking for work and people looking to hire, in an attempt to pair them.
DS18B20 Temperature sensor
The client reported having 4 DS18B20 temp sensors wired up to a Raspberry Pi 2 or 3 (unspecified). Searching Google yielded a supported python library called W1ThermSensor.
The W1ThermSensor library is easy to use and it was very quick to learn the basics from the python.org wiki page.
Features
- Add/remove auto-run at (re)boot (using cron table, previously using rc.local).
- Store settings/preferences in a local file and apply them on program start.
- Auto-save settings/preferences.
- Automatically detect and use the first 4 temperature sensors that w1thermsensor finds.
- Define maximum/minimum temperature ranges on each sensor; determines when notifications are sent.
- Define a time to wait between sending multiple notifications.
- Specify a gmail account/password to be used as the notification sender, as well as any email which will be the receiver.
- Name each sensor. Very useful for distinguishing between sensors in notification emails and in the sensor settings menu.
- Uses the w1thermsensor built-in temperature conversion (previously used a approximation).
- Prints the temperature of each sensor in the settings menu.
- Name the house (where the Raspberry Pi is). Used for email notifications.
- Runs the temperature monitoring on a separate thread such that the user can change settings/preferences while monitoring is taking place.
The code
import os
import os.path
import re
import time
from datetime import datetime
import smtplib
from w1thermsensor import W1ThermSensor
import sys
from crontab import CronTab
import subprocess
from threading import Threadsensors = []
houseName = "My home"
emailTo = "example@mail.com"
gmailFrom = "working@gmail.com"
gmailPass = "plainTextPassword"
notifTime = 10
settingsDelim = '\n' # might want to change this
cron_job = type('system_cron', (object,), {})()def clr():
os.system("clear")def replace( filePath, text, subs, flags=0 ):
with open( filePath, "r+" ) as file:
fileContents = file.read()
textPattern = re.compile( re.escape( text ), flags )
fileContents = textPattern.sub( subs, fileContents )
file.seek( 0 )
file.truncate()
file.write( fileContents )def addRemoveCron():
clr()
print("Script is added to cron jobs to run at restart: " + str(hasattr(cron_job,"is_valid") and cron_job.is_enabled()))
print("1. Enabled cron job to run script at reboot")
print("2. Disable cron job to run script at reboot")
choice = raw_input(">")
if(choice=="1"):
if(hasattr(cron_job,"is_valid") and cron_job.is_enabled()):
print("Cron job is already enabled!")
raw_input("Press any key to return")
addRemoveCron()
addToStartup()
if(choice=="2"):
if(hasattr(cron_job,"is_valid") and cron_job.is_enabled()):
removeFromStartup()def addToStartup():
global cron_job
system_cron = CronTab()
cron_job = system_cron.new(command="python /home/pi/multipleSensors.py m")
cron_job.every_reboot()
cron_job.enable()
system_cron.write()def removeFromStartup():
global cron_job
system_cron = CronTab()
system_cron.remove(cron_job)
system_cron.write()# Using the built in W1ThermSensor conversion instead
#def cToF(c): # (C * 9/5) + 32 = F
# return (float(c)*(9.0/5.0)+32.0)def loadSettings():
global sensors
global houseName
global emailTo
global gmailFrom
global gmailPass
global notifTimeif(sensors): del sensors[:]
sensors = []
f = open("tempSensors.config")
fc = f.read()
for stri in fc.split(settingsDelim):
if('=' not in stri): continue
fn = stri.split("=")[0]
fv = stri.split("=")[1]
if(fn=="houseName"): houseName = fv
if(fn=="emailTo"): emailTo = fv
if(fn=="gmailFrom"): gmailFrom = fv
if(fn=="gmailPass"): gmailPass = fv
if(fn=="notifTime"):
actualFv = 0
try:
actualFv = int(fv)
except:
actualFv = -1
if(actualFv<1): continue
notifTime = actualFv
if(fn=="sensors"): # sensors=Kitchen~abcd1234f~120~32,Living Room~09123ffff~120~32,...
sensorsToLoad = fv.split(",")
for sen in sensorsToLoad:
if(len(sen.split("~"))<3): continue
newSensor = W1ThermSensor(W1ThermSensor.THERM_SENSOR_DS18B20, sen.split("~")[1])
newSensor.Name = sen.split("~")[0]
newSensor.MaxTrig = int(sen.split("~")[2])
newSensor.MinTrig = int(sen.split("~")[3])
sensors.insert(0, newSensor)
f.close()def saveSettings():
f = open("tempSensors.config", 'w')
f.write("houseName="+houseName+"\n")
f.write("emailTo="+emailTo+"\n")
f.write("gmailFrom="+gmailFrom+"\n")
f.write("gmailPass="+gmailPass+"\n")
f.write("notifTime="+str(notifTime)+"\n")
f.write("sensors=")
for sensor in sensors:
f.write((sensor.Name if hasattr(sensor,"Name") else "Unnamed") + "~" + str(sensor.id) + "~" + str(sensor.MaxTrig) + "~" + str(sensor.MinTrig))
f.write(",")
f.close()def detectSensors(): # removes the old sensor list and fills it with alive sensors
global sensors
if(sensors): del sensors[:]
sensors = []
for sensor in W1ThermSensor.get_available_sensors():
sensor.MaxTrig = 120
sensor.MinTrig = 32
sensors.insert(0, sensor)
print("Detected sensor. ID = %s" % (sensor.id))
raw_input("Press any key to return")def alterTriggers(sens):
#global triggerValues
print("Altering name and trigger values for sensor ID: %s\n\tTrigger high: %d, trigger low: %d" % ((sens.Name if hasattr(sens,"Name") else sens.id), sens.MaxTrig, sens.MinTrig))
newTriggerHigh = raw_input("Enter new trigger high (in F): ")
newTriggerLow = raw_input("Enter new trigger low (in F): ")
newSensorName = raw_input("Enter new name for sensor: ")
actualTriggerHi = 0
actualTriggerLo = 0
try:
actualTriggerHi = int(newTriggerHigh)
actualTriggerLo = int(newTriggerLow)
except:
actualTriggerHi = -1
actualTriggerLo = -1
if(actualTriggerHi<1 or actualTriggerLo<1 or len(newSensorName)<1): return
sens.MaxTrig = actualTriggerHi
sens.MinTrig = actualTriggerLo
sens.Name = newSensorName
saveSettings()def sendAlert(stri):
dt = datetime.now().strftime("%Y-%m-%d %H:%M:%S %p")
message = "From: "+gmailFrom +"\nTo: "+emailTo+"\nSubject: Temperature sensor alert at " + houseName +"!"+"\n\n"+ dt + "\n" + stri
try:
server = smtplib.SMTP("smtp.gmail.com", 587)
server.ehlo()
server.starttls()
server.login(gmailFrom, gmailPass)
server.sendmail(gmailFrom, emailTo, message)
server.close()
# print("Email alert sent!") # don't print, probably will interrupt user input
except: # but print if theres an email issue
print("There was a problem sending a mail alert!")def storeTemps():
global sensors
#global triggerValues
for sensor in sensors:
if(sensor.get_temperature(W1ThermSensor.DEGREES_F)>=sensor.MaxTrig):
sendAlert((sensor.Name if hasattr(sensor, "Name") else sensor.id) + " was triggered for being too hot, reporting in at " + str(sensor.get_temperature(W1ThermSensor.DEGREES_F)))
if(sensor.get_temperature(W1ThermSensor.DEGREES_F)<=sensor.MinTrig):
sendAlert((sensor.Name if hasattr(sensor, "Name") else sensor.id) + " was triggered for being too cold, reporting in at " + str(sensor.get_temperature(W1ThermSensor.DEGREES_F)))def printTemps():
global sensors
inx = 0
for sensor in sensors:
print(str(inx+1) + ". Sensor ID: %s reported %f" % (((sensor.Name if hasattr(sensor, "Name") else sensor.id), sensor.get_temperature(W1ThermSensor.DEGREES_F))))
print("\tTrigger high: %d, trigger low: %d" % (sensor.MaxTrig, sensor.MinTrig))
inx+=1
print("5. Main menu")
opt = raw_input(">")
actualOpt = 0
try:
actualOpt = int(opt)
except:
actualOpt = -1
if(actualOpt<1): return
if(actualOpt<5): alterTriggers(sensors[actualOpt-1])
if(actualOpt==5): pageOne()
printTemps()def changeHouseName():
global houseName
clr()
print("Current house name: "+houseName)
newName = raw_input("New house name: ")
if(len(newName)<1): return
houseName = newName
saveSettings()def changeNotifEmail():
global emailTo
print("Current email getting notifications: "+emailTo)
newEmail = raw_input("New email to get notifications: ")
if(len(newEmail)<1 or '@' not in newEmail): return
emailTo = newEmail
saveSettings()def changeSendingEmail():
global gmailFrom
print("current gmail being used to send notifications: "+gmailFrom)
newEmail = raw_input("New gmail to send notification: ")
if(len(newEmail)<1 or '@' not in newEmail): return
gmailFrom = newEmail
saveSettings()def changeSendingPass():
global gmailPass
print("current gmail password being used to send notifications: "+gmailPass)
newPass = raw_input("New gmail password to send notification: ")
if(len(newPass)<1): return
gmailPass = newPass
saveSettings()def changeWaitingTime():
global notifTime
print("Current time to wait between sending notification: "+str(notifTime)+" seconds")
newTime = raw_input("New time to wait, in seconds, between sending notifications: ")
if(len(newTime)<1): return
actualNewTime = 0
try:
actualNewTime = int(newTime)
except:
actualNewTime = -1
if(actualNewTime<1): return
notifTime = actualNewTime
saveSettings()def emailSetup():
clr()
global emailTo
global gmailFrom
global gmailPass
global notifTime
print("1. Change email getting notifications\n\t"+emailTo)
print("2. Change gmail being used to send notifications\n\t"+gmailFrom)
print("3. Change gmail password\n\t"+gmailPass)
print("4. Change time to wait between notifications\n\t"+str(notifTime)+" seconds")
print("5. Main menu")
navTo = raw_input(">")
actualNavTo = 0
try:
actualNavTo = int(navTo)
except:
actualNavTo = -1
if(actualNavTo<1 or actualNavTo>5): emailSetup()
if(actualNavTo==1): changeNotifEmail()
if(actualNavTo==2): changeSendingEmail()
if(actualNavTo==3): changeSendingPass()
if(actualNavTo==4): changeWaitingTime()
if(actualNavTo==5): pageOne()
emailSetup()def monit():
while(1):
try:
time.sleep(notifTime) # sleep the number of seconds between notification sending
storeTemps() # evaluate temps from sensors and store em in sensorTemps
except KeyboardInterrupt:
return
except:
print("Error in monitor thread\n")
# don't not do nuthin;thre = Thread(target = monit)
thre.daemon = True
threRng = Falsedef monitorForever():
global thre
global threRng
clr()
if(thre.isAlive()):
print("Monitor is running!")
else:
print("Starting to monitor, will send notifications when triggered...")
try:
thre.start()
except:
thre = Thread(target = monit)
thre.daemon = True
thre.start()
print("1. End monitoring")
print("2. Return to main menu and monitor in background")
try:
x = raw_input(">")
except: return # closed without properly ending thread, bad practice
if(x=="1"):
try:
thre._Thread__stop()
pageOne()
except: monitorForever()
if(x=="2"): pageOne()
monitorForever()def pageOne():
clr()
print("1. Set housee name")
print("\t"+houseName)
print("2. Setup sensors")
print("\t"+str(len(sensors))+" sensors active")
print("3. View temperature settings and values")
print("4. Setup notifications")
print("5. Run tempertature monitoring (" + ("not" if (thre.isAlive()==False) else "is") + " running!)")
print("6. Add or remove monitoring from cron jobs")
print("7. Save and exit")
try:
navTo = raw_input(">")
except:
return # exiting without properly closing threads, bad practice
navToActual = 0
try:
navToActual = int(navTo)
except:
navToActual = -1
if(navToActual<1 or navToActual > 7):
pageOne() # back to page 1
if(navToActual==1):
changeHouseName()
if(navToActual==2):
detectSensors()
if(navToActual==3):
printTemps()
if(navToActual==4): emailSetup()
if(navToActual==5):
monitorForever()
if(navToActual==6):
addRemoveCron()
if(navToActual==7):
saveSettings()
if(thre.isAlive()): thre._Thread__stop()
exit(0)
pageOne()pc = "ps -ef | grep -v grep | grep multipleSensors.py | grep -v sudo | grep -v " + str(os.getpid())
process_exists = os.system(pc)
if(process_exists==0):
print("Please only run 1 instance at a time!")
exit(0)if(len(sys.argv)>1 and sys.argv[1]=="m"):
#time.sleep(20)
if(os.path.isfile("tempSensors.config")): loadSettings()
if(thre.isAlive()):
print("Already monitoring!")
else:thre.start()if(os.path.isfile("tempSensors.config")): loadSettings()
pageOne()
