Trend temperature and humidity. Note: only works on a Raspberry Pi with a DHT22 temp/humidity sensor.

PLAYDOUGH_WEATHER.rb

#!/usr/bin/env ruby 
require 'json'
NORMAL = 1
DEGRADED = 2
EXCESSIVE = 3
DOWN = 4

def is_number? string
  true if Float(string) rescue false
end

dht22reading = `sudo AdafruitDHT.py 22 4`
tempC = dht22reading.split(' ').first.split('=').last.to_f
tempF = (tempC * 1.8000 + 32.00).round(2)

humidity = dht22reading.split(' ').last.split('=').last.to_f.round(2)

# TODO: Drive the numbers off config
tempState = !is_number?(tempF) ? DOWN : (tempF > 78 ? EXCESSIVE : (tempF > 72 ? DEGRADED : NORMAL))
humidityState = !is_number?(humidity) ? DOWN : (humidity > 50 ? EXCESSIVE : (humidity > 40 ? DEGRADED : NORMAL))

if tempC == 0 && humidity == 0
   data = {
      :availability => 0,
      :temperature_state => 3,
      :humidity_state => 3,
   }
else
   data = {
      :temperature => tempF,
      :humidity => humidity,
      :temperature_state => tempState,
      :humidity_state => humidityState
   }
end
puts data.to_json.gsub(/"/, "'")