This Lego Weather Station is an exercise in IoT concepts using an Arduino (Cactus Micro Rev2) which has a built-in ESP8266 WiFi module. It then sends the sensor data using MQTT to a Mosca MQTT broker. A Node-RED client subscribes to the data feed, stores it into a MongoDB and then visualizes it with a Google Chart. The blog article is more about the journey than just the destination . This is one of many cool projects in the Internet of Lego city, which examines all sorts of interesting embedded, NodeJS and IoT concepts using Lego.  Full Story: Weather Station – DHT11, MQTT, Node-RED, Google Chart, Oh My! | Internet of Lego