Device for converting a movement of a user into a voltage

1. A device for converting a movement of a user into a voltage, the device comprising:

a neck cord;

a piezoelectric sensor coupled to the neck cord, wherein the piezoelectric sensor has at least one end point and is bendable relative to a plane including the at least one end point; and

a printed circuit board, coupled to the piezoelectric sensor, wherein the neck cord is arranged to provide in use a pulling force acting on the piezoelectric sensor in a first direction, a weight of the printed circuit board causes a gravity force to act on the piezoelectric sensor in a second direction being different from the first direction such that the movement of the user wearing the neck cord results in a change in the shape of the piezoelectric sensor, the piezoelectric sensor generating the voltage in response to the change in the shape.

2. The device according to claim 1 wherein the piezoelectric sensor is shaped as a rectangular element having two opposite end portions and a middle portion, the element being bendable relative to a plane crossing the end portions, the neck cord being coupled to the end portions of the element, the printed circuit board being mechanically coupled to the middle portion of the element.

3. The device according to claim 1 wherein the piezoelectric sensor is shaped as a rectangular element having two opposite end portions and a middle portion, the element being bendable relative to a plane crossing the end portions, the neck cord being coupled to the middle portion of the element, the printed circuit board being mechanically coupled to the end portions of the element.

4. The device according to claim 1 wherein the piezoelectric sensor comprises two rectangular shaped elements, each element having first and second end portions, each element being bendable relative to a plane crossing its end portions, the neck cord being coupled to the first end portions and the printed circuit board being mechanically coupled to the second end portions.

5. The device according to claim 2 wherein the printed circuit board is positioned perpendicular relative to the plane.

6. A device for monitoring a user comprising the device according to claim 1 wherein the device for monitoring a user further comprises a filter arranged for filtering the generated voltage, the device further comprising an electronic component being arranged to switch from a standby state to an operating state in dependence of the filtered generated voltage exceeding a threshold.

7. The device for monitoring a user according to claim 6 wherein the device is further arranged to transmit a control signal in response to the electronic component switching from the standby state to the operating state.

8. The device for monitoring a user according to claim 6 wherein the electronic component is a processor and/or a movement sensor for measuring the movements of the user.

9. The device for monitoring a user according to claim 6 wherein the electronic component is further arranged to switch from the operating state to the standby state a predetermined time after the voltage is below a further threshold.

10. A fall detector comprising the device for monitoring a user according to claim 6 wherein the electronic component is a movement sensor for measuring the movements of the user, the device further comprising a processor, the processor being arranged to switch from a standby state to an operating state in dependence of a wake up signal received from the movement sensor, the processor being further arranged to process the measurements from the movement sensor to detect a potential fall of the user, the fall detector being further arranged to transmit an alarm signal in response to the processor having detected a possible fall.

11. A system for monitoring a user comprising a base station arranged for receiving the control signal transmitted by the device for monitoring a user according to claim 9 , the base station being further arranged to send a warning signal when no control signal has been received for a predetermined time period.

12. A method of converting a movement of a user into a voltage, the method comprising the steps of:

applying a pulling force, via a neck cord, to a piezoelectric sensor in a first direction, wherein the piezoelectric sensor has at least one end point and is bendable relative to a plane including the at least one end point;

applying a second force to the piezoelectric sensor in a second direction via a weight of a printed circuit board coupled to and acting on the piezoelectric sensor in the second direction and the pulling force passed on by the neck cord in the first direction to the piezoelectric sensor cause a change in the shape of the piezoelectric sensor, wherein the piezoelectric sensor generates a voltage corresponding to the change in the shape.

13. The method of monitoring a user comprising the method of converting a movement of a user into a voltage according to claim 12 , the method of monitoring a user further comprising the steps of

filtering the generated voltage;

comparing the filtered voltage generated by the piezoelectric sensor with a threshold;

switching an electronic component from standby to operating when the filtered voltage exceeds the threshold.

14. The method of monitoring a user according to claim 13 further comprising the step of:

transmitting a control signal in response to electronic component switching from the standby state to the operating state.

15. The method of detecting a potential fall comprising the method of monitoring a user according to claim 13 and further after the electronic component is switched to operating comprising the steps of:

monitoring with a movement sensor the movements of the user;

processing the measurements from the movement sensor with a processor to detect a potential fall of the user.