Abstract: A spa communication system for establishing a communication link between a central spa box having a control module and spa components in a spa system. The spa control module is connected to the spa components through a communication link, and the spa control module sends command signals to at least one spa component and receives status information from at least one spa component on the communication link.

Abstract: A water temperature control circuit for a washing machine includes window detector and dual water valve drivers to modulate the hot and cold water valves to maintain the water temperature at a desired level. A temperature selector switch provides hot, regulated hot, warm, regulated warm, and cold temperature settings for the washing machine. During regulated temperature operation the window detector modulates one of the water valves to maintain the water temperature within a narrow temperature band. The window comparator includes two comparators that receive a common temperature input from a temperature sensing element. As such, no shunt resistor is required for one or the other comparators, thus improving accuracy. The control circuit operates open loop with respect to the hot and cold water valves that it controls, utilizing instead only the temperature input for controlling the proper water valve when enabled.

Abstract: A driver circuit for a latching type valve is provided which utilizes an electronic switch assembly to provide the dual polarity necessary to actuate the latching type valve to both its open and closed states. The driver circuitry includes a microprocessor and a slope detector circuit for monitoring the coil current used to energize the valve solenoid to determine when the valve armature has moved to its fully actuated position. The driver circuit preferably utilizes power MOSFET devices in the switch assembly configured into an H-bridge to drive the solenoid coil. Advantageously, the user of power MOSFET devices eliminates the necessity for a current sense resistor in the control circuitry, thereby decreasing power dissipation and increasing efficiency of the drive circuit, thereby prolonging the battery life used to drive the valve.

Abstract: A precharged capacitor connected in parallel with the contacts of an open switch discharges through the switch upon closure. Oxides on the switch contacts are broken through upon closure of the switch to produce a good electrical connection. The capacitor provides sufficient voltage and transient current to clean the switch contacts. A microprocessor having signals of only 5 volts can interrogate a plurality of such switches by multiplexing some semiconductor switching circuits that energize the interrogated switches and by synchronously multiplexing some microprocessor input circuits. The microprocessor's input circuits therefore receive signals indicating the status of each switch in turn.

Abstract: Disclosed are two arrangements for remotely indicating the status of a washing machine and/or a dryer. In one arrangement, a current sense circuit is employed along with an optional vibration sense circuit to detect whether or not the washing machine or the dryer are on or off. At a change from on-to-off or from off-to-on, the status of the washing machine or dryer is transmitted over the air to a receiver for status display to the operator. In the second arrangement, detection of the status is internal to the washing machine and the dryer and the status includes additional information such as the type of cycle and the amount of time left before the cycle finishes. To avoid constant transmission of such information, the receiver includes a timer which is synchronized to the washing machine/dryer timing circuits.