We have developed a board based on PIC microcontroller which is able to generate 1kHz PWM signal, detect the vehicle and control the relay. It is also possible to adjust PWM width for current regulation. The board is small enough to be installed directly into J1772 Yazaki connector.
See also the EVSE section at GWL/Power blog http://gwl-power.tumblr.com/tagged/EVSE
If you wish to buy a complete product see the EVCharge product section
This kit includes following parts:
To make your own charging station you will also need some soldering skills, wires, outdoor box and also a propper connector (Yazaki, Mennekes...)!
Here is an example use of this kit: