Reduced power consumption low battery alert device

• US 4,660,027 A
• Filed: 08/31/1984
• Issued: 04/21/1987
• Est. Priority Date: 08/31/1984
• Status: Expired due to Fees

• Current Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Davis, Walter L.
• Primary Examiner(s): Rowland, James L.
• Assistant Examiner(s): Hofsass, Jeffery A.
• Application Number:
  US06/646,618
• Time in Patent Office: 963 Days
• Field of Search: 340/636, 340/635, 340/660, 340/661, 340/691, 324/426, 324/436, 324/435, 324/433, 324/133, 320/48, 320/13, 429/92, 429/61
• US Class Current: 340/636.15
• CPC Class Codes: G08B 21/185 Electrical failure alarms

Abstract

A reduced power consumption low battery indicator comprising in the preferred embodiment a transducer driver which drives a transducer to provide an audible alert. A microprocessor is used to generate a squarewave signal to power the transducer driver whenever the battery is depleted to a first predetermined level. A first low battery sensor is used to determine when the battery is depleted to the first predetermined level and generates a signal which is directed to the microprocessor to commence generation of the signal to drive the transducer driver. A second low battery sensor is used to determine when the battery is depleted to a second predetermined level and generates an output signal which is directed to the transducer driver which then drives the transducer at a lower power consumption rate.

Claims

1. A depleted battery indicator for a device being powered by a battery, said battery indicator comprising:

audio annunciator means for providing an audible alert;

circuit means, connected to said annunciator means, for determining when said battery has been depleted to a first predetermined voltage and generating a first signal to activate said annunciator means whereby said alert is provided at a first power level and for determining when said battery has been depleted to a second predetermined voltage and generating a second signal to further activate said annunciator means whereby said alert is provided at a second power level wherein said second power level is less than said first power level, thereby prolonging battery life.

2. The device, according to claim 1, wherein said circuit means comprising:

comparator means, for generating said first signal whenever the battery voltage decreases to said first predetermined voltage.

3. The device, according to claim 1, wherein said circuit means comprising:

comparator means, for generating said second signal whenever the battery voltage decreases to said second predetermined voltage.

4. The device, according to claim 1, wherein said circuit means further comprising:

processor means for generating a signal to turn on said annunciator means; and

first voltage comparator means, connected to said processor means, for generating said first signal whenever the battery voltage decreases to said first predetermined voltage whereby said annunciator means turn on signal is generated by said processor means and said alert is provided at said first power level.

5. The device, according to claim 4, wherein said circuit means further comprises:

second voltage comparator means, connected to said annunciator means, for generating said second signal whenever the battery voltage decreases to said second predetermined voltage whereby said alert is provided at said second power level.

6. A depleted battery indicator for a device being powered by a battery, said battery indicator comprising:

a transducer, for generating an audible alert;

transducer driver means, connected to said transducer, for driving said transducer;

processor means, connected to said transducer driver means, for generating a turn-on signal to activate said transducer driver means whereby said transducer generates said audible alert;

first voltage comparator means, connected to said processor means, for generating a first signal whenever the battery voltage decreases to a first threshold voltage whereby said turn-on signal is generated by said processor means and causes said transducer to be driven at a first power level;

second voltage comparator means, connected to said transducer driver means, for generating a second signal whenever the battery voltage decreases to a second threshold voltage which causes said transducer to be driven at a second power level wherein said second power level is less than said first power level, thereby prolonging battery life.

7. A depleted battery indicator for a device being powered by a battery, said battery indicator comprising:

audio annunciator means for providing an audible alert;

circuit means, connected to said annunciator means, for determining when said battery has been depleted to a predetermined voltage and generating a first signal which causes said annunciator means to provide said alert at a first power level and for generating a second signal at a predetermined time after said first signal is generated which causes said annunciator means to provide said alert at a second power level wherein said second power level is less than said first power level, thereby prolonging battery life.

8. The device, according to claim 7, wherein said circuit means comprising:

voltage comparator means for generating said first signal whenever said battery is depleted to said predetermined voltage.

9. The device, according to claim 7, wherein said circuit means comprising:

processor means, connected to said annunciator means, for generating a turn-on signal to activate said annunciator means whenever said first signal is generated and for generating said second signal at said predetermined time after said first signal is generated.

10. The device, according to claim 8, wherein said circuit means further comprising:

processor means, connected to said comparator means and said annunciator means, for generating said turn-on signal to activate said annunciator means whenever said first signal is generated and for generating said second signal at said predetermined time after said first signal is generated.

11. The device, according to claim 9, wherein said processor means comprising:

timer means for counting said predetermined time after said first signal is generated.

12. The device, according to claim 10, wherein said processor means comprising:

timer means for counting said predetermined time after said first signal is generated.

13. A depleted battery indicator for a device being powered by a battery, said battery indicator comprising:

a transducer for generating an audible alert;

transducer driver means, connected to said transducer, for driving said transducer;

voltage comparator means, connected to said battery, for comparing the battery voltage to a reference voltage and generating a first signal whenever said battery voltage decreases to a threshold voltage;

processor means, connected to said transducer driver means and said comparator means, for generating a turn-on signal to activate said transducer driver means whenever said first signal is generated which causes said transducer to be driven at a first power level, said processor means including a timer means for timing a predetermined time period after said first signal is generated, said processor means for generating a second signal to said transducer driver means after said predetermined time period which causes said transducer to be driven at a second power level wherein said second power level is less than said first power level, thereby prolonging battery life.

14. A method of indicating a depleted battery in a device being powered by a battery and having an audio annunciator means for generating an audible alert, comprising the steps of:

determining when said battery has been depleted to a first predetermined voltage;

activating said annunciator means to generate said alert at a first power level;

determining when said battery has been depleted to a second predetermined voltage;

further activating said annunciator means to generate said alert at a second power level wherein said second power level is less than said first level, thereby prolonging battery life.

15. The method, according to claim 14, wherein said step of determining when said battery is depleted to a first predetermined voltage comprises the step of:

comparing the battery voltage to a reference voltage and generating a signal which indicates that said battery voltage has decreased to said first predetermined voltage.

16. The method, according to claim 14, wherein said step of determining when said battery is depleted to a second predetermined voltage comprises the step of:

comparing the battery voltage to a reference voltage and generating a signal which indicates that said battery voltage has decreased to said second predetermined voltage.

17. A method of indicating a depleted battery in a device being powered by a battery and having an audio annunciator means for generating an audible alert, comprising the steps of:

determining when said battery has been depleted to a predetermined voltage;

activating said annunciator means to generate said alert at a first power level;

further activating said annunciator means to generate said alert at a second power level a predetermined time after said battery has been depleted to said predetermined voltage wherein said second power level is less than said first power level, thereby prolonging battery life.

18. The method, according to claim 17, wherein said step of determining when said battery is depleted to a predetermined voltage comprises the step of:

comparing the battery voltage to a reference voltage and generating a signal which indicates that said battery voltage has decreased to said predetermined voltage.

19. The method, according to claim 17, wherein said step of activating said annunciator means to generate said alert at a first power level comprises the step of:

starting a timing means which generates a signal after said predetermined time period has elapsed.