Vehicle Loop Detector-2

Origional Project Created: "Mar 20, 2010"
This Project put on this website: June 6, 2011
REVISED August 12, 2014.

I have recieved Numerous Requests for a circuit to detect Vehicles
using a Buried Coil.
This is a REVISED, More Stable circuit than my Other Car Loop detector.


The Part Number "CE-04" is available from me. The PCB and Complete Kit of parts is also available from me. (Excluding the Coil)


1) First set the Fine Trimpot to a Mid Position. 2) Next set the Coarse Trimpot so the LED JUST Lights with NO METAL Near the Coil. 3) Now adjust the Fine Trimpot, so the LED Just goes Off.        NOTE: It MAY need a Slight Re-Adjust after a few minutes. The Precise Setting of the Controls can also Determine Sensitivity.

Coils of almost any Shape, Size or diameter are possible. For a Car, I would suggest a 4 foot diameter or Square Shape Coil. Or Rectangular Shapes can also work well.

This Circuit is for a Real Car or Truck, Maybe a motorcycle. It is NOT for detecting Small "Model Cars". As it does Not work well on Small Objects.

There are TWO SEPERATE COILS: Both Coils should be firmly taped Together, so the coil wires don't move within themselves or each other. If the wires are not stable, it will cause inductance changes resulting in frequency drift.

The Coil gets Buried where its Needed and the Circuit should go inside your House or Garage. Normally no special wire is needed to join it to the circuit board, unless it is really a long distance. Than possibly use a Coax cable for each coil. Also, Make Sure Coil Phasing is wired Correctly to the PCB or it Won't Work.

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Loop Detector-2 Schematic. NOTE:  The CE-04 Part is a Custom Made, In-House Part
and is Available from me.

Loop Detector-2 PCB.

Overlay Picture.

A Smaller Coil. I Wind my coils on a Wood Frame that has a
SAW CUT on the Outer Edge to hold the Wire.

A Larger Coil. I Wind my coils on a Wood Frame that has a
SAW CUT on the Outer Edge to hold the Wire.

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Chemelec *Copyright © 2010 & 2014*