I work for a company that utilizes loops cut into the road to detect the presence of a vehicle. The devices are made by Federal APD. There are more than one loop in a lane.
I am an old grey Electronics Technician from the US Navy. I know that these loops are the inductive element of a tuned tank circuit of an LC or LR oscillator. I am not privy to the schematics.
So, the controller is operating, and the tank is operating, at about 200Khz.
I don't want to know if the loop is working or not, the controller can tell me that.
I want a simple probe that I can plug into my Fluke DMM to locate where the loop actually is under the pavement/concrete. It would also serve to quickly show if a loop was working or not.
Preferably, it would have a focussed point on the end of a wand/handle. A hall-effect transistor could detect magetism. Since the loop in the ground is, basically, a metal-detector, How can I detect the coil's electromagnetic field?
It only needs to be sensive enough so that when the sensor is within 2 or 3 inches of the coil wires, it produces a noticeable increase in DC or AC voltage on my DMM.
Any ideas?
I can make my own PCB's. This would be a very profitable device in the industry I work in. If I could buy all the parts for less than $40, I can make the circuit board, test it, Then sell these to the company I work for at $180 a piece. We can sell them for more to other interests.
I can use a fox/hound device on a loop when the loop is not connected. Fox/hound devices cost > $280. Thus my efforts.
Email: <snip>
Thanks!
I am an old grey Electronics Technician from the US Navy. I know that these loops are the inductive element of a tuned tank circuit of an LC or LR oscillator. I am not privy to the schematics.
So, the controller is operating, and the tank is operating, at about 200Khz.
I don't want to know if the loop is working or not, the controller can tell me that.
I want a simple probe that I can plug into my Fluke DMM to locate where the loop actually is under the pavement/concrete. It would also serve to quickly show if a loop was working or not.
Preferably, it would have a focussed point on the end of a wand/handle. A hall-effect transistor could detect magetism. Since the loop in the ground is, basically, a metal-detector, How can I detect the coil's electromagnetic field?
It only needs to be sensive enough so that when the sensor is within 2 or 3 inches of the coil wires, it produces a noticeable increase in DC or AC voltage on my DMM.
Any ideas?
I can make my own PCB's. This would be a very profitable device in the industry I work in. If I could buy all the parts for less than $40, I can make the circuit board, test it, Then sell these to the company I work for at $180 a piece. We can sell them for more to other interests.
I can use a fox/hound device on a loop when the loop is not connected. Fox/hound devices cost > $280. Thus my efforts.
Email: <snip>
Thanks!
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