For our PNP Project we need a way to switch main power for our Vacuum pump and Compressed Air Pump for Dispenser and PNP Header. First I wanted to use a esp8266 WIFI Chip and an Solid State Relay (SSR). But i found a finished solution:
https://www.itead.cc/sonoff-wifi-wireless-switch.html ~$5
The alternative version, use an esp8266 and a Solid State Relay, here some stuff
http://www.ebay.de/itm/351584833428 SSR-Relay
http://www.ebay.de/itm/121734485794 3.3V power supply
But the first one are better, hopefully i can sniff the network protocol 
http://blog.brianmoses.net/2015/12/sonoff-and-slampher-home-automation-review.html