Inductive Loop Detector works by detecting an inductance change in wire loop (coil) that is buried in road. It does that by measuring the frequency of the internal oscillator which powers the mentioned coil. When a metallic object moves over the coil it changes its inductance and that in turn changes the oscillator frequency which is measured by the microcontroller. We can provide pre-programmed PIC chip to meet your requirement on this project.
It is used for vehicle access control at door and barrier controls, for monitoring the occupancy and for vehicle counting in parking garages, for traffic light installations and traffic controllers, for direction and speed detection of vehicle traffic, in car-wash plants, etc. This device can also work as an independent speed trap and can be easily interfaced to Arduino.
Specifications
Number of operating modes: 4
Tuning: Automatic
Detection type: Presence/Pulse
Presence time: Adjustable in 3 steps
Pulse duration: 250 ms / 500 ms
Signal filtering: Adjustable in 2 steps (NORMAL, HIGH)
Loop inductance: 20 uH – 1000 uH
Frequency range: 20 kHz – 145 kHz
Frequency selection: 2 combinations (LOW, HIGH)
Sensitivity: Maximum 0.0025% Δf/f, adjustable in 8 steps
Detection speed: 10 ms by default, adjustable
Start-up time: ~ 1 second per channel (or longer if frequency is not stable)
Temperature range: -35°C – 120°C
Sensor protection: Galvanic isolation + gas discharge tube for lightning protection