Freetronics reseller Hadley Rich from nicegear has published an effective way of measuring household power consumption using a Freetronics EtherTen board, MQTT and some external hardware. Hadley's power meters each have an LED that blinks 1600 times per kWh used, which is just perfect for monitoring. Using a photocell taped (and covered!) to the front of the meter it can detect the pulses, which are then fed to the EtherTen via a simple circuit. The data is then published to the network using the MQTT protocol for other devices to read.
In this case a python server receives the data over the network and logs it for graphing. An interesting and simple solution to what can often though to be a complex problem, so for more information visit the project page. And for more, we're on twitter and Google+, so follow us for news and product updates as well.
When putting together your next Internet-enabled Arduino project - save time, space and money with the Freetronics EtherTen. Apart from being fully Arduino Uno-compatible, it has onboard Ethernet, microSD socket, full USB interface (so you don't need a costly FTDI cable just to upload a sketch!) and supports optional Power-over-Ethernet. For more information and to order, click here.