| Summary: | 碩士 === 明新科技大學 === 電子工程研究所 === 101 === The main drawback of common passive infrared sensing devices PIR is the failure in determining the changes in the environment, especially the slow-moving people within the range of detection since in the detection range the temperature of the object is not changed, it causes false positives in the PIR using the scheme. Active infrared sensors can improve the above shortcomings, however, the effective distance is mostly limited to three meters. A reflecting mirror is usually used to increase the reflection distance. The thesis is focused on the design and implementation of the active infrared sensing system, this system use of common electronic components, and design the preamplifier, amplifier, filter, rectifier, ADC conversion circuit with a Microcontroller Unit to determine the changes in the environment. We also use the program filter to reduce the sunlight error range. When the environmental changeover, the LED of our system will indicate this situation. This detection range changing can be interfaced through MATLAB software. Our system also improves the performance for the detection range to more than three meters. Finally, the application automatic doors and automatic lamp depict the correctness.
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