This Spa controller, developed by Richard Wotiz, is a winner of 2007 Microchip 16-bit embedded control design contest in CircuitCellar. Controller is able to drive 2HP single phase AC motor. Circuit operates with capacitor-start/capacitor-run motors. It also includes active power factor correction and inrush current limiting.
Motor driver is controlled by 16-bit dsPIC30F2020 microcontroller which drives motor via three phase IGBT power module. Spa controller can be connected to separate interface unit which is based on PIC16F687 where pump can be controlled by using while messages are displayed on LCD. Full project entry is here.