1. Field of the Invention
This invention relates to an improved remote control system for a combined ceiling fan and light fixture and, more particularly, to a system of this type using a radio frequency link, microprocessor control, and a number of special features.
2. Description of the Prior Art
Ceiling fans are often combined with light fixtures, and it is desirable to provide remote control means for controlling fan speed and direction as well as light intensity. One such remote control system is shown in U.S. Pat. No. 4,719,446, issued Jan. 12, 1988 to Edward F. Hart. This system uses existing house wiring to couple control signals from a wall mounted control unit to control the speed of the fan and the intensity of the light. However, systems of this character require access to an AC line by replacing a wall switch and are subject to line noise. Such systems are difficult to operate in that fan and light operations are sometimes confused. Moreover, the prior art systems do not readily lend themselves to the incorporation of special features. Fan motors of the prior art are typically connected across an AC power supply through triacs which, in conventional practice, are triggered continuously. The commutating effect of back EMF from the motor causes the triac to go to zero at some point other than true AC zero cross, thus causing the triac to fall out of conduction. Although continuous triggering is effective, the prior art fan motors tend to have high power dissipation causing the motor to run hot.