Use an ESP-12 module (ESP8266 radio) to broadcast ADC readings from an SCT-013 current sensor or any other analog sensor connected to the sensor pins. Uses through-hole components for simplicity in revision 1.0. See the GitHub repository https://github.com/kasparsd/wiku for the latest updates.
The first revision prototype boards have arrived. There is something drastically wrong with the 3.3V power regulator wiring. The MCP1702 regulator (pdf) requires a few passives to actually do anything.
Secondly, the GPIO15 pin has to be tied to GND which is currently missing from the circuit.
I also received a few of the ESP-12S chips. Here a the instructions for updating the official AT firmware to the latest version 3.0: