A method of enabling a user computing device to manage a controlled device only when the computing device is physically proximate to the controlled device, comprising: repeatedly broadcasting, by the controlled device, a rotating code over a short range wireless communication channel from a user computing device, wherein: the rotating code changes after expiration of a time period, and the short range wireless communication channel has a wireless communication range that allows the user computing device to receive the broadcast rotating code only when the user computing device is positioned physically proximate to the controlled device (300, 402, 502), repeatedly receiving (402, 404, 502, 306), by the controlled device, a code from the user computing device, via the short range communication channel or a further communication channel that is different from the short range communication channel; determining, in response to receiving each code from the user computing device via the first or second communication channel, whether each received code corresponds to the rotating code most recently broadcast via the first communication channel; granting (312, 313), in response to determining that each code corresponds to the most recently broadcasted rotating code, the user computing device an access to manage the controlled device; and denying, in response to determining that each received code does not correspond to the most recently broadcasted rotating code, the user computing device the access to manage the controlled device. repeatedly broadcasting, by the controlled device, a rotating code over a short range wireless communication channel from a user computing device, wherein: the rotating code changes after expiration of a time period, and the short range wireless communication channel has a wireless communication range that allows the user computing device to receive the broadcast rotating code only when the user computing device is positioned physically proximate to the controlled device (300, 402, 502), the rotating code changes after expiration of a time period, and the short range wireless communication channel has a wireless communication range that allows the user computing device to receive the broadcast rotating code only when the user computing device is positioned physically proximate to the controlled device (300, 402, 502), repeatedly receiving (402, 404, 502, 306), by the controlled device, a code from the user computing device, via the short range communication channel or a further communication channel that is different from the short range communication channel; determining, in response to receiving each code from the user computing device via the first or second communication channel, whether each received code corresponds to the rotating code most recently broadcast via the first communication channel; granting (312, 313), in response to determining that each code corresponds to the most recently broadcasted rotating code, the user computing device an access to manage the controlled device; and denying, in response to determining that each received code does not correspond to the most recently broadcasted rotating code, the user computing device the access to manage the controlled device.