US Patent 11143642 Graphene-based indicator

A sensor product for detecting an analyte or condition. The sensor product having a body and a circuit integrated with the body. The circuit including an electric power source, a sensing element comprising graphene or a graphene derivative in which the sensing element is configured to undergo a change in an electrical property in the presence of an analyte or condition, and an indicator configured to display information indicating the presence of the analyte or condition when the change in an electrical property of the sensing element occurs. For instance, the indicator may display “DANGER EVACUATE” in the presence of chlorine gas, elevated temperatures, or other analytes or conditions.