Illumination systems, which include at least one light source (e.g., LED and/or laser diode), light sensor, and a power source are described. In certain embodiments, a light sensor and a microprocessor are used to detect light emitted by a light source and to adjust the power signal provided to the light source at least partially based on the detected light. Some embodiments may enable the color point and/or brightness of the emitted light to be controlled at least partially based on the detected light. The illumination systems may be designed to be used as a liquid crystal display (LCD), general lighting apparatus, or any other illumination device.