DataDog has a simple API for sending measurements to which you post JSON with an array of data points and a unix timestamp. Then you can make up dashboards with graphs like this:
The temperature and humidity sensor is one I grabbed at Jaycar, they call it a Duinotech XC4432 that contains a DHT11 sensor. Unfortunately the resolution seems only to be a degree so I'm waiting for something better to come in the post.
Because DataDog wants a time stamp with every reading, I get the time from an NTP server. The code is mushed together from three samples:
- DHTester from Ladyada
- The ESP8266 BasicHttpClient (but using POST instead of GET)
- The UdpNtpClient from the Ethernet library
I'm using GPIO 2 on the esp8266 to read the sensor.