Roving collector

A system comprising:

• a plurality of dual-mode devices without an Internet connection geographically distributed, a first mode associated with a dual-mode device in the plurality of dual-mode devices comprising a high-energy mode to record data or to transmit the recorded data upon receiving a signal, wherein the plurality of dual-mode devices do not communicate with each other, and a second mode associated with the dual-mode device comprising a low-energy mode to determine whether to transition to the first mode;
• and
• a collecting device to transition a subset of the plurality of dual-mode devices into the first mode.

A method comprising:

• determining, by a processor associated with a dual-mode device operating in a low-energy mode, whether a wake-up condition has been satisfied by monitoring properties of an environment surrounding the dual-mode device, the wake-up condition excluding a communication from another dual-mode device;
• and
• reducing energy consumption of the dual-mode device by operating the dual-mode device in a high-energy mode during a task associated with the wake-up condition and transitioning the dual-mode device to the low-energy mode upon completion of the task.

A system comprising:

• a plurality of off-line sensors without an Internet connection distributed over an environment and operating in at least two modes, a first mode comprising a high-energy mode to record an environment property associated with the environment or to transmit the recorded environment property upon receiving a signal from a collecting device, wherein the plurality of off-line sensors do not communicate with each other, and a second mode comprising a low-energy mode to monitor an environment and to determine whether to activate the first mode;
• and
• the collecting device to transition a subset of the plurality of off-line sensors into the first mode.