Samer and I have slowly started working on our next gadget, the OpenThermostat. Part of the design of OpenSprinkler 3.0 is to make the main (ESP8266) processor board separate from the solenoid driver board, so that the same processor board can be plugged into different driver board (such as an HVAC) board to make other controllers. The circuit is fairly easy to design but it’s the software that’s going to take a while to finish.