Patent ID: 11927472
Assignee: AMAZON TECHNOLOGIES, INC.
Field: Measurement (Instruments)
Classification: CPC G  H | IPC G  H

Claim 3:
4. The materials handling facility of claim 1, wherein the photovoltaic power source is in communication with the computer system, and
wherein the one or more sets of instructions, when executed, further cause the computer to at least:
receive, from the photovoltaic power source, information regarding a first level of electrical energy generated by at least the first photovoltaic cell from light emitted by at least the light source at a first time;
receive, from the photovoltaic power source, information regarding a second level of electrical energy generated by at least the first photovoltaic cell from light emitted by at least the light source at a second time, wherein the second time is after the first time;
determine that the second level of electrical energy is less than the first level of electrical energy; and
in response to determining that the second level of electrical energy is less than the first level of electrical energy,
determine that the transaction occurred at the second time.