Device and method for alerting a runner when a new pair of running shoes is needed

1. A device for determining the wear of a sole of a shoe, comprising:

a first sensor receivable in the sole of the shoe, the first sensor generating a first signal in response to a first impact force thereon;

a second sensor receivable in the sole of the shoe at a location vertically spaced from the first sensor, the second sensor generating a second signal in response to a second impact force thereon; and

a control circuit connectable to the first and second sensors, the control circuit determining a difference between the first and the second sensor signals, generating an alert signal in response to the difference meeting a predefined criteria.

2. The device of claim 1 wherein the first sensor is a pressure sensor.

3. The device of claim 2 wherein the second sensor is a pressure sensor.

4. The device of claim 1 wherein the control circuit includes:

a first amplifier for amplifying the first signal; and

a second amplifier for amplifying the second signal.

5. The device of claim 4 wherein the control circuit includes a differential amplifier for determining a difference between the first amplified signal and the second amplified signal and for amplifying the difference between the first amplified signal and the second amplified signal.

6. The device of claim 5 wherein the control circuit includes a comparator for comparing the amplified difference between the first amplified signal and the second amplified signal with a threshold and for generating an illumination signal if the amplified difference between the first amplified signal and the second amplified signal meets the threshold.

7. The device of claim 6 wherein the control circuit includes a light emitting diode, the light emitting diode generating the alert signal in response to the illumination signal.

8. A device for determining the wear of a sole of a shoe, comprising:

a first pressure sensor receivable in the sole of the shoe, the first sensor generating a first signal that is proportional to a first impact force acting thereon;

a second pressure sensor receivable in the sole of the shoe at a location vertically spaced from the first pressure sensor, the second sensor generating a second signal that is proportional to a second impact force acting thereon; and

a control circuit connectable to the first and second pressure sensors, the control circuit comparing the difference between the first and second signals to a threshold and generating an alert signal in response to the difference between the first and second signal meeting the threshold.

9. The device of claim 1 wherein the control circuit includes:

a first amplifier for amplifying the first signal; and

a second amplifier for amplifying the second signal.

10. The device of claim 9 wherein the control circuit includes a differential amplifier for determining the difference between the first amplified signal and the second amplified signal and for amplifying the difference between the first amplified signal and the second amplified signal.

11. The device of claim 10 wherein the control circuit includes a comparator for comparing the amplified difference between the first amplified signal and the second amplified signal with the threshold and for generating an illumination signal if the amplified difference between the first amplified signal and the second amplified signal meets the threshold.

12. The device of claim 11 wherein the control circuit includes a light emitting diode, the light emitting diode generating the alert signal in response to response to the illuminating signal.

13. The device of claim 8 wherein the control circuit is enclosed in a capsule.

14. A method for measuring the wear of a sole of a shoe, comprising the steps:

measuring an impact force exerted on a first portion of the sole of the shoe;

measuring an impact force exerted on a second portion of the sole of the shoe at a location vertically spaced from the first portion;

comparing the impact force exerted on the first portion of the shoe and the impact force exerted on the second portion of the shoe; and

generating an alert signal if the difference between the impact force exerted on the first portion of the shoe and the impact force exerted on the second portion of the shoe meets a threshold.

15. The method of claim 14 wherein the sole of the shoe includes a midsole affixed to an upper surface of an outsole and wherein the method includes the additional steps of:

positioning a first sensor between the outsole and the midsole to measure the impact force exerted on the first portion of the shoe; and

positioning a second sensor on an upper surface of the midsole to measure the impact force exerted on the second portion of the shoe.

16. The method of claim 15 wherein the first sensor and the second sensor are axially aligned.

17. The method of claim 15 wherein the step of comparing the impact force exerted on the first portion of the shoe and the impact force exerted on the second portion of the shoe includes the additional steps of:

generating a first signal that is proportional to a first impact force;

generating a second signal that is proportional to a second impact force acting thereon;

amplifying the first and second signals; and

determining the difference between the first amplified signal and the second amplified signal.

18. The method of claim 15 comprising the additional steps of:

providing a control circuit to compare the impact force exerted on the first portion of the shoe and the impact force exerted on the second portion of the shoe and to generate the alert signal; and

enclosing the control circuit in a capsule.

19. The method of claim 18 comprising the additional step of interconnecting the capsule to the shoe.

20. The method of claim 15 comprising the additional step of illuminating a light emitting diode in response to the alert signal.