Capacitive detection, energy transfer, and/or data transfer system

1. A system comprising a base and at least a first moveable entity, the first moveable entity being separate to and freely moveable with respect to the base and positionable in at least a first position with respect to the base,

the base comprising at least a first base electrode, and the moveable entity comprising at least a first moveable entity electrode, and

the first base electrode and the first moveable entity electrode being arranged to couple to form a first capacitor when the first moveable entity is in the first position,

the base further comprising signal supply means, arranged to supply a first time-varying electrical Signal to the first base electrode, and

the first moveable entity further comprising circuitry connected to the first moveable entity electrode,

wherein the base is arranged to power the circuitry via the time-varying electrical signal and the coupling between the first base electrode and the first moveable entity electrode when the first moveable entity is in the first position, and

wherein the time-varying electrical signal carries data and the circuitry is arranged to detect the data when the first moveable entity is in the first position.

2. A system in accordance with claim 1 , wherein the base further comprises Signal detection means arranged to detect an electrical signal from the first base electrode.

3. A system in accordance with claim 2 , wherein the signal detection means is adapted to determine whether the first moveable entity is in the first position from the electrical signal from the first base electrode.

4. A system in accordance with claim 2 , wherein the signal detection means is adapted to determine an identity of the first moveable entity when the first moveable entity is in the first position from the electrical signal from the first base electrode.

5. A system in accordance with claim 2 , wherein the circuitry is arranged to provide a second time-varying electrical signal to the first moveable entity electrode, the second time-varying electrical signal carrying second data, and the signal detection means is adapted to detect the second data when the first moveable entity is in the first position.

6. A system in accordance with claim 1 , wherein the circuitry comprises:

a first node, connected to the first moveable entity electrode, a second node, and a third node;

a first diode connected between the first node and the second node to allow current flow from the first node to the second node and block current flow from the second node to the first node; and

a second diode connected between the third node and the first node to allow current flow from the third node to the first node and block current flow from the first node to the third node.

7. A system in accordance with claim 6 , wherein the circuitry further comprises a second capacitor connected between the second node and the third node.

8. A system in accordance with claim 7 , wherein a voltage is developed across the second capacitor in response to the first time-varying electrical signal being applied to the first base electrode when the first moveable entity is in the first position.

9. A system in accordance with claim 6 , wherein the circuitry further comprises a resistor connected between the second node and the third node.

10. A system in accordance with claim 9 , wherein an electrical current is driven through the resistor in response to the first time-varying electrical signal being applied to the first base electrode when the first moveable entity is in the first position.

11. A system in accordance with claim 6 , wherein the circuitry further comprises data detection means connected to the second and third nodes and adapted to detect data carried by the first time-varying electrical signal from a signal developed between the second and third nodes when the first moveable entity is in the first position.

12. A system in accordance with claim 6 , wherein the circuitry further comprises data transmission means connected to the second and third nodes and adapted to supply a second time-varying electrical signal carrying second data to the first moveable entity electrode.

13. A system in accordance with claim 11 , wherein the circuitry further comprises power supply circuitry connected to the second and third nodes, adapted to receive power via the second and third nodes when the first moveable entity is in the first position, and adapted to power at least one of the data detection means and the data transmission means using the received power.

14. A system in accordance with claim 1 , wherein the first moveable entity comprises a first portion, and a second portion attached to the first portion, wherein the second portion comprises the first moveable entity electrode and the circuitry.

15. A system in accordance with claim 14 , wherein the second portion is a label attached to a surface of the first portion.

16. A system in accordance with claim 14 , wherein the first portion comprises a container.

17. A system in accordance with claim 16 , wherein the container is one of: a plastic container, and a metal container.

18. A system in accordance with claim 16 , wherein the container is at least partly filled with liquid or solid contents.

19. A system in accordance with claim 14 , wherein the coupling between the first base electrode and the first moveable entity electrode to form the first capacitor is at least partly via the first portion.

20. A system in accordance with claim 19 , wherein the first portion comprises a container having a wall, and optionally at least partly filled with contents, and the coupling is at least partly via the wall, and optionally at least partly via the contents.