Quote:
Originally Posted by FreelancerMG
It's not the disturbance per se of the magnetic field directly that the sensors pick up but the disturbance created by eddy currents which change the field and the sensors monitor. The eddy currents don't get extra powerful if done from purely a magnetic field, otherwise a copper wire based electromagnet would be the best solution. The eddy currents play across the surface of the metal and it's these eddy currents which create a disturbance in the field that the sensors measure. Your magnet works since it's still in practice a flat piece of iron that's real close to the ground. A really thin piece of sheet steel should work wonders and with how low a bike sits, should actually do a better job than the axle of a car due to sheer flat surface area. Also, aluminum foil theoretically should be able to produce a similar, if not reduced effect. So I want to someday try lining the belly pan of my bike with aluminum foil and see if the magnetic field on induction loops are designed similarly as some metal detectors are. Ask a metal detecting enthusiast how many aluminum cans they've dug up because their detector called it a coin.
I used to have the national Department of Transportation's Traffic engineering and design handbook in digital format and it goes in length on theory of operation and design. A very interesting read for the few of us that like that sorta thing.
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always good to know...
do you think that something like steel wool would produce more eddy currents as steel wool is ALL surface area?
Dead red laws are great, I used to get trapped in South Carolina, they have divided 2 lane roads, with a median in the middle... when you are in the left turn lane, you are committed to the turn, no way to get back on the road with out driving through the grass, or pushing the bike backwards. I would blow the reds after waiting and waiting... but didn't have any kind of legal protection if some LEO wanted to be a wiener.