One of IoT application for the smart home: electronic appliance energy monitoring. I used Sonoff PoW as the measuring and switching device. To be integrated only into our private network, we need to flash the firmware. I used Tasmota’s ESP8266 firmware (https://github.com/arendst/Sonoff-Tasmota) and followed the instruction given in the web (Disclaimer: you have to solder some pins inside the module and because of that, the warranty expires and it could not redo if failed).
Workflow is needed to transfer the data from the sensor to the storage (I used InfluxDB as the storage). For that purpose, node-red was chosen due to its light load.
I used Grafana to visualize the readings stored in InfluxDB.
The collected data could then be used to predict an operation anomaly and energy consumption, e.g., http://redd.csail.mit.edu/