temp2.py

#!/usr/bin/env python3

# Andrew Pattison, 11/10/2012 - 25/10/2012
# script to update cosm graphs using 2 sensors:
# 1. CPU temperature sensor built into CPU
# 2. Ambient temperature sensor on the I2C bus
# N.B. For some reason, the bash script that I
# previously used to update cosm occasionally caused
# cosm to report wierd temperatures like -913456 celcius
# for the CPU temperature
# so I do some basic sanity checking on the reading before
# sending it to cosm just to be on the safe side

# Errors are logged to syslog

import quick2wire.i2c as i2c
import time
import json
import http.client
import syslog
import sys

# I2C address of temperature sensor
address = 0x48

while True:
    try:
        with i2c.I2CMaster() as bus:
            sensora, sensorb = bus.transaction(i2c.writing_bytes(address, 0x00),i2c.reading(address, 2))[0]
            temp = (sensora << 8 | sensorb) / 256.
            tempstring = "{0:.2f}".format(temp)
            print ("Ambient temperature: %02.02f" % temp)

        file = open("/sys/class/thermal/thermal_zone0/temp", "r")
        string = file.readline()
        file.close()
        cputemp = float(string) / 1000
        if cputemp > 0:
            # normal reading from CPU temp sensor, so send to cosm
            cputempstring = "{0:.2f}".format(cputemp)
            upload = { "version": "1.0.0", "datastreams": [
            { "id":"RoomTemperature", "current_value":tempstring },
            { "id":"CPUTemperature", "current_value":cputempstring }
            ]
            }
        else:
            # abnormal reading from CPU temp sensor, so DON'T send to cosm
            cputempstring = "0.00"
            upload = { "version": "1.0.0", "datastreams": [
            { "id":"RoomTemperature", "current_value":tempstring }
            ]
            }
        print(cputempstring)
        print(json.dumps(upload))
        print("About to send data to cosm...")

        connection = http.client.HTTPConnection("api.cosm.com")
        data = json.dumps(upload)
        header = { "X-ApiKey":"<your key goes here>" }
        connection.request("PUT", "/v2/feeds/79499/", data, header)
        result = connection.getresponse()
        print("HTTP status code from cosm server: " + str(result.status))
        print("Finished sending data to cosm")

        if result.status == 200:
            if cputemp > 0:
                logstring = "CPU temp=" + cputempstring + ", room temp=" + tempstring
            else:
                logstring = "room temp=" + tempstring
            # syslog.syslog("Successfully sent data to cosm: " + logstring)
        else:
            syslog.syslog("Error sending data to cosm. HTTP response code: " + str(result.status))
        time.sleep(60)
    except Exception:
        # N.B. we are still within the while loop!
        print ("An exception occured: 0=" + str(sys.exc_info()[0]) + ", 1=" + str(sys.exc_info()[1]) + ", 2=" + str(sys.exc_info()[2]))
        syslog.syslog("An exception occured: 0=" + str(sys.exc_info()[0]) + ", 1=" + str(sys.exc_info()[1]) + ", 2=" + str(sys.exc_info()[2]))
        syslog.syslog("Pausing for 60 seconds to see if error condition clears...")
        time.sleep(60)
        syslog.syslog("Attempting to continue where I left off...")