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DIY USB charger

20160920_222327-2I got a hold of a USB outlet from ebay, and I wanted to use it basically as a hub for charging. I sourced a 3A 12V plug-type power supply which I figured would work well with the ‘UBEC‘ 5V buck converter I got made for RC plane receivers, changed the UBEC cables to DC barrel jacks and. hmm doesn’t work.. :/

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Monitoring RPi Temp and CPU with Thingspeak

I made the following python script to update CPU Temperature and 5 minute average CPU load of my RPi to Thingspeak:

#!/usr/bin/env python
import subprocess
import httplib, urllib

GetTempCommand = "cat /sys/class/thermal/thermal_zone0/temp"
GetCPUCommand = "cat /proc/loadavg"

GetTempProcess = subprocess.Popen(GetTempCommand.split(), stdout=subprocess.PIPE)
GetTempOutput = GetTempProcess.communicate()[0]
Temp = float(GetTempOutput) / 1000
#print Temp
GetCPUProcess = subprocess.Popen(GetCPUCommand.split(), stdout=subprocess.PIPE)
GetCPUOutput = GetCPUProcess.communicate()[0]
CPU = GetCPUOutput.split()
#print CPU[1]

params = urllib.urlencode({'field1': CPU[1],'field2': Temp, 'key':'######'})     # use your API key generated in the thingspeak channels for the value of 'key'
# temp is the data you will be sending to the thingspeak channel for plotting the graph. You can add more than one channel and plot more graphs
headers = {"Content-typZZe": "application/x-www-form-urlencoded","Accept": "text/plain"}
conn = httplib.HTTPConnection("api.thingspeak.com:80")                
try:
    conn.request("POST", "/update", params, headers)
    response = conn.getresponse()
    data = response.read()
    conn.close()
except:
    print "connection failed"

The script is run every 5 mins using cron ($ crontab -e):

*/5 * * * * python "/home/ubuntu/logging/TempCPUtoThingspeak.py"

I borrowed some script from here and here.