This study proposes a low-cost and reliable smart fire alarm system that utilizes ultraviolet (UV) detection technology with an aspherical lens to detect fires emitting photons in the 185–260 nm range. The system integrates the aspherical lens with an accelerator and a digital compass to determine the fire source’s direction, allowing for safe evacuation and effective firefighting. Artificial intelligence is employed to reduce false alarms and achieve a low false alarm rate. The system’s wide detection range and direction verification make it an effective fire detection solution. Upon detecting a fire, the system sends a warning signal via Wi-Fi or smartphone to the user. The proposed system’s advantages include early warning, a low false alarm rate, and detection of a wide range of fires. Experimental results validate the system’s design and demonstrate high accuracy, reliability, and practicality, making it a valuable addition to fire management and prevention. The proposed system utilizes a parabolic mirror to collect UV radiation into the detector and a simple classification model that uses Fourier transform algorithm to reduce false alarms. The results showed accuracies of approximately 95.45% and 93.65% for the flame and UVB lamp, respectively. The system demonstrated its effectiveness in detecting flames in the range of up to 50 m, making it suitable for various applications, including small and medium-sized buildings, homes, and vehicles.

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This paper proposes a method for high-precision radius measurements. The proposed system uses a frequency-modulation technique to improve the accuracy of detecting cat’s eye and the confocal position of a lens. The distance between two points defined as the radius of a lens was measured by using a frequency-modulated Michelson interferometer. In the confocal part, when the tested lens was moved along the optical axis, the intensity at the detector reaches a maximum at the confocal and cat’s eye positions of the sphere. Synchronous detection technique is used to turn the intensity signal from the detector into an odd-symmetry signal through a zero point. These symmetry points coincide with cat’s eye and confocal positions and thus enhance the accuracy with which these two points are detected. A frequency-modulated Michelson interferometer is used to accurately measure the displacement when moving the test sphere between the confocal and cat’s eye points.