A method for a light bulb or fixture to emit light and measure ambient light. The method includes driving solid state light sources, such as LEDs, in the bulb with a cyclical signal to repeatedly turn the solid state light sources off and on, where the light sources are turned off and on at a rate sufficient for the bulb to appear on. The method also includes measuring ambient light via a light sensor in or on the bulb during at least some times when the light sources are off, and outputting a signal related to the measured ambient light. The ambient light level signal can be used to control when the light bulb is on and an intensity of light output by the bulb.