US 5,633,625 AGranted

Electronic chime module and method

AssigneeSaturn Electronics & Engineering, Inc.

InventorsGuy J. Gaub, Ray M. Hallenbeck

Life of this patent

Estimating the term…

Loading patent…

Abstract

An exponentially decaying chime sound is generated with a single tri-statable output pin from a microprocessor which is implemented using a single digital output pin line to create states of low, high and disconnect which are input to a control circuit for output to a speaker. Preferably, the control circuit comprises a low pass filter in series with a buffer. Preferably, the buffer is a Darlington transistor. Preferably, the speaker is an electro-mechanical device, alternatively it may be a piezo-resistive device. A method is disclosed for generating a desired audible chime signal with a chime generating circuit regulating a tri-statable output via a single pin of a microprocessor to approximately generate a desired signal frequency, and preferably includes regulating said tri-statable output to produce amplitude decay of the desired signal frequency over time.

Claims19

Dependent claims

Chime generating circuitry, for use in a vehicle control system having a control means for monitoring the status of a vehicle condition, comprising:

(a) an oscillator circuit connected to a microcontroller;
(b) a microcontroller comprised of:
a microprocessor having a central processing unit, random access memory and read only memory,
a plurality of inputs for monitoring the status of a vehicle condition including a first input for receiving a seat belt unbuckled signal, a second input for receiving a door open signal, a third input for receiving a key in the ignition signal, fourth input for receiving a signal from an accessory, each of said inputs being operable to transmit said signals from said inputs to said microprocessor,
a single tri-statable output operable to generate a time-varying digital output signals, the tri-statable output having at least three states including an on-state, an off-state, and a high-impedance disconnect state, said high-impedance disconnect state being used to help generate a sinusoidal signal by repetitively holding the output signal at an intermediate level for a predetermined time period;
(c) a control circuit comprising:
a single stage low-pass filter circuit having an input receiving the digital output signal from said single tri-statable output and a first output for producing a first output voltage,
a buffer having an input and an output, said input receiving said first output voltage from said low-pass filter circuit, said buffer output being operable to drive a tone-generating device.

5 more elements

Chime generating circuitry, for use in a vehicle control system having a control means for monitoring the status of a vehicle condition, comprising:

a microprocessor-based chime control means, including a microprocessor having at least one tri-statable output, for generating a time-varying digital output signal, the tri-statable output having at least three states, including an on-state, an off-state and a high-impedance state, the digital output signal at the tri-statable output being controlled by the microprocessor so as to generate an approximate sinusoidal waveform for producing a corresponding exponentially decaying sinusoidal signal to an audio output device which in turn creates a corresponding decaying chime sound the approximate sinusoidal waveform including a plurality of periods during each sinusoidal cycle wherein the tri-statable output is placed in its high-impedance state for a predetermined length of time each period;
a low pass filter means having an input and an output, said input receiving the digital output signal from the tri-statable output;
a buffer means having an input and an output, said input of said buffer means receiving output from said filter means and said output of said buffer means producing a signal for delivery to a tone-generating audio output device.

Dependencies are inferred from the claim text.