Low-power wake-up mechanism for wireless devices

1. A wireless communications system comprising:

a first wireless device comprising

a primary wireless transceiver;

a secondary wireless receiver; and

an electronic processor configured to

operate the first wireless device and communicate through the primary wireless transceiver when in an active mode,

monitor the secondary wireless receiver for a wake-up signal when the first wireless device is in a sleep mode, and

transition the first wireless device from the sleep mode to the active mode in response to detecting the wake-up signal through the secondary wireless receiver, and

a second wireless device, wherein

the first wireless electronic device is configured to monitor the secondary wireless receiver for the wake-up signal by monitoring an antenna for a binary high signal at a defined number of intervals according to a first duty cycle, and

wherein the second wireless electronic device is configured to monitor a wireless receiver for a second wake-up signal by monitoring an antenna of the second wireless electronic device for a binary high signal at a second defined number of intervals according to a second duty cycle, the second duty cycle being different from the first duty cycle.

2. The wireless communications system of claim 1 , wherein the secondary wireless receiver includes a dedicated wireless radio device that is separate from components of the primary wireless transceiver.

3. The wireless communications system of claim 1 , wherein the primary wireless transceiver includes a primary antenna, a sampling circuit, and a primary radio electronic processor, and

wherein the secondary wireless receiver includes the antenna and a second radio electronic processor.

4. The wireless communications system of claim 3 , wherein the primary radio electronic processor operates in a reduced power mode when the first wireless electronic device is in the sleep mode.

5. The wireless communications system of claim 1 , wherein the electronic processor is configured to disable communication through the primary wireless transceiver when in the sleep mode.

6. The wireless communications system of claim 5 , wherein the electronic processor is configured to disable communication through the secondary wireless receiver when in the active mode.

7. The wireless communications system of claim 1 , further comprising a wireless signal source configured to

transition both the wireless electronic device and the second wireless electronic device from the sleep mode into the active mode by transmitting a first wake-up signal configured to provide a binary high signal according to both the first duty cycle and the second duty cycle, and

transition the wireless electronic device, and not the second wireless electronic device, from the sleep mode into the active mode by transmitting a second wake-up signal configured to provide a binary high signal according to the first duty cycle and not according to the second duty cycle.

8. The wireless communications system of claim 1 , further comprising:

a wireless signal source configured to transmit the wake-up signal; and

a redundant wireless signal source configured to detect the wake-up signal transmitted by the wireless signal source and to re-transmit the wake-up signal to the second wireless electronic device, wherein the redundant wireless signal source is positioned between the wireless signal source and the second wireless electronic device.

9. The wireless communications system of claim 1 , wherein the second wireless electronic device is further configured to detect a trigger event and, in response to the trigger event, transmit a trigger signal to a wireless signal source, and further comprising a wireless signal source configured to transmit the wake-up signal to the first wireless electronic device in response to receiving the trigger signal from the second wireless electronic device.