Chameleon inspired high-temperature thermochromic traffic light type photonic crystal sensors toward early fire detection and visual sensing

Fire detection plays a crucial role in maintaining the safety of people's lives and property. However, most early fire detectors are designed to monitor the current or voltage changes of the sensing materials, which require external power supplies. It is still a challenge to make rapid and accurate noncontact early fire detection in precombustion due to the lack of reliable alarm signals. Herein, inspired by the discoloration of chameleon skin, we developed an early fire warning sensor (EFWS) by coating photonic crystals (PCs) on a plastic sheet with thermal expansion properties. Monodispersed zinc sulfide (ZnS) was coated on the plastic sheet as abnormal detection component for EFWS. Combined with the intelligent image recognition algorithm, the EFWS was designed and gave warnings for 0.9 s at 260 °C. For the first time, a photonic crystal-based non-contact real-time monitoring EFWS in precombustion is developed. The sensing material can be directly pasted on the surface of the detected equipment, and combined with existing surveillance cameras in the detection area, early warning of fires can be achieved. The EFWS system can be used in non-open fire alarms for aircraft, buildings, electrical appliances, substations, and other places in the future.