Just how cold is that window? Winter monitoring with the TI Sensortag, Node-RED, and Freeboard

Our living room has lovely (old) wooden windows. When it's cold, the windows get cold. Last year we got some lovely thermal curtains to insulate. I thought I'd use some of the equipment I had to see just how cold the windows were and how much warmer the curtains are to the touch. The setup: Macbook Air running OS X 10.9 (Mavericks), Node-RED 0.9.1, Freeboard, TI Sensortag. I'm using RabbitMQ as my MQTT message passing system, but that's not strictly necessary for this application. »