STEP COUNTER DEVICE WITH ENERGY-SCAVENGING FUNCTIONALITY, AND STEP-COUNTING METHOD

• US 20140088917A1
• Filed: 09/24/2013
• Published: 03/27/2014
• Est. Priority Date: 09/26/2012
• Status: Active Grant

• Current Assignee: STMicroelectronics International N.V. (STMicroelectronics NV)
• Original Assignee: STMicroelectronics SRL (STMicroelectronics NV)
• Inventors: Gasparini, Alessandro, Ramorini, Stefano, Cattani, Alberto
• Granted Patent: US 9,587,959 B2
• Time in Patent Office: Days
• US Class Current: 702/160
• CPC Class Codes: A43B 3/38 with power sources
• CPC Class Codes: A43B 3/42 where power is generated by conversion of mechanical movement to electricity, e.g. by piezoelectric means
• CPC Class Codes: G01C 22/006 Pedometers
• CPC Class Codes: H02M 7/219 in a bridge configuration

Abstract

A step-counter device detects and counts user steps. The device includes a transducer configured to generate an electrical transduction signal in response to user stepping. An energy-scavenging system is coupled to the transducer to generate a power supply voltage in response to the electrical transduction signal. A processing unit is powered by the power supply voltage. The processing unit is further configured to sense the electrical transduction signal and determine whether a user step has occurred and in response to that determination increment a step counter.

Claims

1. A step-counter device, comprising:

a transducer configured to generate an electrical transduction signal as a function of mechanical activity generated during stepping;

a processing unit configured to determine a step based on said electrical transduction signal and consequently increment a step count; and

an energy-scavenging system coupled to said transducer and configured to generate electrical energy for supplying said processing unit from said electrical transduction signal generated as a function of the mechanical activity generated during stepping.

2. The device according to claim 1, wherein said processing unit is configured to detect execution of a step upon occurrence of a characteristic pattern in a plot of said electrical transduction signal.

3. The device according to claim 2, wherein said characteristic pattern comprises the presence, within a given time interval, of a first significant portion and a second significant portion of said electrical transduction signal, having positive and negative polarities, respectively.

4. The device according to claim 1, wherein said transducer is of an electromagnetic type and has a characteristic inductance.

5. The device according to claim 4, wherein said energy-scavenging system comprises an interface stage having a first input terminal and a second input terminal coupled to said transducer and configured to define a switching converter using the characteristic inductance of said transducer.

6. The device according to claim 5, wherein said processing unit includes sensing inputs connected to said first input terminal and said second input terminal of said interface stage, the processing unit configured to process a first signal and a second signal present on said first input terminal and second input terminal, respectively, to determine execution of a step.

7. The device according to claim 6, wherein said energy-scavenging system comprises a storage capacitor on which an output voltage is present, said storage capacitor connected between a first output terminal and a second output terminal of said interface stage;

and wherein said first input terminal and said second input terminal are selectively switched, by said processing unit, in connection to a reference voltage or to said output voltage.

8. The device according to claim 6, wherein said first signal and said second signal are constituted by a plurality of pulses, and wherein said processing unit is configured to determine execution of a step upon detection of a given number of pulses of said first signal and second signal within a given time interval.

9. The device according to claim 5, wherein said energy-scavenging system comprises a storage capacitor on which an output voltage is present, said storage capacitor connected between a first output terminal and a second output terminal of said interface stage;

and wherein said interface stage comprises a logic control unit and a set of switches designed to be controlled in switching by said logic control unit for cyclically causing storage of energy in said inductor in a first interval of a switching period, and transfer of energy onto said storage capacitor in a second interval of the switching period, at both polarities, positive and negative, of the electrical transduction signal.

10. The device according to claim 9, wherein said logic control unit is configured for controlling switching of said set of switches to optimize a coupling efficiency between said transducer and said interface stage.

11. The device according to claim 10, wherein said first interval has a duration T_delay and wherein a ratio k is present between the value of the current circulating in said inductor at the end of said first interval and the value of the current circulating in said inductor at the end of said second interval;

wherein said logic control unit is configured to set the values of said duration T_delay and of said ratio k to optimize said coupling efficiency.

12. The device according to claim 1, wherein said energy-scavenging system comprises a voltage-regulator stage configured to generate a regulated voltage for supplying said processing unit;

and wherein said processing unit is configured to monitor the value of said regulated voltage and to enable detection of the execution of a step only in the case where said regulated voltage has a value higher than a pre-set threshold.

13. The device according to claim 1, further comprising a transmission stage operable in response to said processing unit for making a wireless transmission of information associated to said count.

14. The device according to claim 1, having a housing designed to be coupled to a shoe of said user.

15. A method, comprising:

carrying out an operation of transduction for generating an electrical transduction signal as a function of mechanical activity generated during stepping; and

determining from analysis of said electrical transduction signal that a step has occurred and enabling an incrementing of a step count;

wherein carrying out an operation of transduction comprises carrying out an operation of energy scavenging starting from said mechanical activity generated during stepping for the generation of electrical energy on the basis of said electrical transduction signal.

16. The method according to claim 15, wherein determining comprises detecting execution of a step upon occurrence of a characteristic pattern in the plot of said electrical transduction signal.

17. A device, comprising:

a motion transducer configured to generate an electrical transduction signal in response to applied motion;

an energy scavenging device configured to convert said electrical transduction signal into a power supply voltage; and

a processing device powered from said power supply voltage and having a sensor input coupled to receive the electrical transduction signal, said processing device configured to analyze the electrical transduction signal for the purpose of detecting a certain type of applied motion.

18. The device of claim 17, wherein said certain type of applied motion is a human step motion, said processing device further configured to increment a step counter in response to detection of said human step motion.

19. The device of claim 18, wherein said processing device is configured to detect said human step motion in response to detection of a characteristic pattern in a plot of the analyzed electrical transduction signal.

20. The device of claim 19, wherein said characteristic pattern comprises, within a time interval, the presence of a positive polarity signal portion and a negative polarity signal portion.

21. The device of claim 17, wherein the electrical transduction signal comprises a positive electrical transduction signal and a negative electrical transduction signal, and wherein said sensor input comprises a positive sensor input configured to receive the positive electrical transduction signal and a negative sensor input configured to receive the negative electrical transduction signal, said processing device analyzing the positive and negative electrical transduction signals for indication of the certain type of applied motion.

22. The device of claim 21, wherein operation of the energy scavenging device causes pulsation of the positive and negative electrical transduction signals, and wherein the analysis performed by said processing device comprises counting pulses in said the positive and negative electrical transduction signals in comparison to positive and negative threshold counts to make a detection of the certain type of applied motion.