Sense household power (blinking led) and transmit to server over WIFI.

This project will consist of several parts which together will measure the blinks generated by common household power meters and upload the measurements to a server. In my case the power meter emits 10000 blinks per KWh, so each measured blink is 0.1 Wh. By storing the blink count every few seconds to few minutes it is possible to se the impact of using the oven, microwave, water heater etc.

The main parts are

• Client hardware
• Client software
• Server software

Each part will be described below.

Initially an Arduino UNO (easy prototyping), a photo transistor (for detecting the blinks) and a WiFly (for communicating with the server).

The photo transistor will generate an interrupt.

The client will wakeup periodically and send the blink counter value to the server using the WiFly module. Initially each wakeup will initiate a data transfer, but later on many datapoints can be stored locally and uploaded later to save bandwidth and allow for temporary connection issues.

Each interrupt will increase the blink counter.

Software running in a "cloud" environment and will initiall just allow for the client to store the data and have an API for fetching the stored data. Later will be increased to have a user interface for plotting the data.