An Implementation of Programmable Oscillator for Inductive-Loop Vehicle Sensor Using Low-Cost Microcontroller

this paper presents the implementation of automatic oscillator tuning for inductive loop vehicle sensor. The implementation is based on a series of an oscillator, a resonance circuit, and microcontroller to capture the output of the resonance circuit. Three programmable oscillators are proposed and compared. The experiment was done on 24 combinations of loop wire and capacitor to simulate the different real-world scenarios. The results are concluded that the proposed method is correctly locating the resonance frequency and create output signal that highly distinctive between positive and negative detected case.