Abstract: A door chime system includes a microcontroller having a processor and a data memory for storing digital sound files. The microcontroller includes an input and an output representative of digital sound files; a door chime actuator having an output responsive to the depression of the doorbell electrically connected to the input of said microcontroller and an amplifier stage for converting a one of said digital sound files into sound. The output from the microcontroller representative of a digital sound file is supplied to the input of the amplifier stage responsive to the door chime output.

Abstract: A method and circuit arrangement dynamically calibrate a photosensitive control for a light source that includes a voltage divider circuit coupled to a resistive light detector and configured to output to a comparison circuit a variable voltage signal that varies with the resistance of the resistive light detector. To calibrate the photosensitive control, a variable impedance circuit in the voltage divider circuit is adjusted to null out any changes in voltage caused by feedback from the controlled light source. The amount of correction is proportional to the amount of light feedback. Based on the amount of correction needed, a new reference voltage is selected that will accurately detect the next dusk to dawn transition while the light feedback is present.

Abstract: A MP3 chime player and display device having a MP3 microcontroller unit being integrated with an in-store display. The in-store display of the present invention has MP3 play selection buttons and associated selection insignia. The microcontroller is in electronic communication with a reprogrammable digital storage device, an electronic port, speakers, volume controls, as well as buttons on the button board or in-store display.