Method and system for configuring electrical contacts in electrical device

1. A primary device for connecting to a secondary device, comprising:

at least three electrical contacts;

a voltage source; and

a controller,

wherein each electrical contact of said at least three electrical contacts has an associated high switch connected between the electrical contact and the voltage source, and an associated low switch disposed between the electrical contact and electrical ground, and

wherein the controller is connected to each of the low switches and the high switches and is configured to sequentially close a plurality of pairs of switches to connect the voltage source to the secondary device during an orientation operation, each pair of switches comprising a high switch associated with one of the electrical contacts and a low switch associated with another of the electrical contacts, and is further configured to record a voltage difference between the electrical contacts associated with each of the plurality of pairs of switches, and to determine an orientation of the secondary device relative to the primary device based on the recorded voltage differences.

2. The primary device according to claim 1 , wherein the controller is further configured to close at least one low switch and at least one high switch in response to the determined orientation of the secondary device.

3. The primary device according to claim 2 ,

wherein the primary device is an electrical charging device, and

wherein the controller is further configured to close at least one low switch and at least one high switch in response to the determined orientation of the secondary device prior to a charging operation.

4. The primary device according to claim 1 , wherein each of the low switches and the high switches is a transistor.

5. The primary device according to claim 1 , further comprising a nonvolatile memory storing a record of expected voltage differences between the electrical contacts associated with each of the plurality of pairs of switches for each of a plurality of orientations,

wherein the controller is further configured to compare voltage differences recorded during the orientation operation with the expected voltage differences to determine the orientation of the secondary device.

6. The primary device according to claim 1 , further comprising a current limiting resistor connected in parallel with a current limiting switch between the voltage source and the at least three electrical contacts,

wherein the controller is further configured to hold the current limiting switch open during the orientation operation.

7. The primary device according to claim 1 , further comprising at least five electrical contacts.

8. An electrical system comprising a primary device and a secondary device,

the primary device comprising:

at least three electrical contacts,

a voltage source, and

a controller; and

the secondary device comprising a plurality of electrical contacts associated with different functions and being configured to engage the electrical contacts of the primary device in a plurality of orientations,

wherein each electrical contact of said at least three electrical contacts has an associated high switch connected between the electrical contact and the voltage source and an associated low switch disposed between the electrical contact and electrical ground, and

wherein the low switches and the high switches are configured to sequentially close a plurality of pairs of switches to connect the voltage source to the secondary device during an orientation operation, each pair of switches comprising a high switch associated with one of the electrical contacts and a low switch associated with another of the electrical contacts, and is further configured to record a voltage difference between the electrical contacts associated with each of the plurality of pairs of switches, and to determine an orientation of the secondary device relative to the primary device based on the recorded voltage differences.

9. The electrical system according to claim 8 , wherein the secondary device further comprises a diode connected between each pair of electrical contacts among the plurality of electrical contacts on the secondary device.

10. The electrical system according to claim 8 , wherein the primary device and the secondary device each have at least five electrical contacts.

11. The electrical system according to claim 8 , wherein the secondary device comprises a secondary battery.

12. A method of determining an orientation of a secondary device relative to a primary device to which the secondary device is connected, the primary device comprising at least three electrical contacts, a voltage source, and a controller, the secondary device having a plurality of electrical contacts associated with different functions of the secondary device and wherein the electrical contacts on the secondary device are configured to engage the electrical contacts of the primary device in a plurality of orientations, wherein each electrical contact of said at least three electrical contacts has an associated high switch connected between the electrical contact and the voltage source and an associated low switch disposed between the electrical contact and electrical ground, the method comprising:

sequentially closing a plurality of pairs of the switches to connect the voltage source to the secondary device, each pair of the switches comprising a high switch associated with one of the electrical contacts and a low switch associated with another of the electrical contacts;

recording a voltage difference between the electrical contacts associated with each of the plurality of pairs of switches; and

determining the orientation of the secondary device relative to the primary device based on the recorded voltage differences.

13. The method according to claim 12 ,

wherein the primary device further comprises a nonvolatile memory storing a record of expected voltage differences between the electrical contacts associated with each of the plurality of pairs of the switches for each of the plurality of orientations, and

wherein the method further comprises comparing the voltage difference recorded during an orientation operation with the expected voltage differences to determine the orientation of the secondary device.

14. The method according to claim 13 , wherein a digital interpretation of an expected voltage difference between the electrical contacts associated with a first pair of switches is undefined among a high value of 1 and a low value of 0.

15. A method of charging a secondary device connected to a primary device, the primary device comprising at least three electrical contacts, a voltage source, and a controller, the secondary device having a plurality of electrical contacts associated with different functions of the secondary device and wherein the electrical contacts on the secondary device are configured to engage the electrical contacts of the primary device in a plurality of orientations, wherein each electrical contact in the primary device has an associated high switch connected between the electrical contact and the voltage source and an associated low switch disposed between the electrical contact and electrical ground, the method comprising:

determining an orientation of the secondary device relative to the primary device by:

sequentially closing a plurality of pairs of switches to connect the voltage source to the secondary device, each pair of the switches comprising a high switch associated with one of the electrical contacts and a low switch associated with another of the electrical contacts,

recording a voltage difference between the electrical contacts associated with each of the plurality of pairs of switches, and

determining the orientation of the secondary device relative to the primary device based on the recorded voltage differences;

closing at least one low switch and at least one high switch in response to the determined orientation of the secondary device; and

providing a charging current from the primary device to the secondary device through at least one of the closed switches.