Simple service plugin that read values from a url that returns json formated values. I used to read values from my thingspeak channel.
edit service.py and fill in the thingspeak api key and the channel id variable
Add $INFO[Window(Home).Property(thingspeak)] to one of the xml (for example the home.xml) files from your skin, this will be replaced by the values from thingspeak.
Launch Kodi >> Add-ons >> Get More >> .. >> Install from zip file
Feel free to ask any questions on the Kodi Forums.
Enjoy!