Traffic Light Triggers
Discussion:
Forum thread on this topic: 12/18/08: http://forums.delphiforums.com/yamaha1100/messages?msg=38710.1
-- appears there are some folks for whom the big magnet dos not work, even!
BUT . . . . (Thanks to Route6T6 !)
I just saw this very topic on the new Science Channel show called "Brink" (ep 4). Their 'Gadget Guru' did a segment stating that it does work, and how to go about installing a small, powerful Neodymium magnet. That a bar magnet shape was best in order to orient the poles horizontally and left to right (perpendicular to center line of the vehicle); also the further apart the poles are, or the longer the magnet, the more effective.
That would explain why speaker magnets and other round designs are less effective; their poles are oriented to the flat surfaces, which would make it vertical when stuck to the bottom surface of the vehicle.
They pointed out that you could use double stick tape if there were no magnetic surfaces down low enough (more likely on mostly plastic scooters).
Daddo (DaddoCFL):
Are you tired of getting stuck at traffic lights because your bike is too small to be detected by the inductive loop buried in the pavement.
Traffic signal sensors are essentially metal detectors buried in the road surface. These "inductive loop" sensors are easy to spot because they have a circular, square, or diamond-shaped saw cut in the pavement just before the intersection. There is a weak radio frequency field over the coil, and a large inductive mass disturbs that field. Loop detectors are meant to pick up the presence of large masses of metal - like cars and trucks - sitting still over the detector loop.
Most modern bikes don't have enough inductive material in their frames to trip the sensor, and what they have tends to be oriented vertically above the loop (making it harder to sense) so we get stuck.
A powerful magnet emits a wide and powerful magnetic field that when passed over a detector loop, disturbs the loop's field, simulating the arrival of a much larger vehicle. When the control computer sees that signal, it knows someone's there, and the biker gets a green light, just like everyone else.
You can spring for $14.95 for the commercially available Green Light Trigger, or you can cough up $24.95 the "New High Power" Green Light Trigger. These are small magnets that are secured to the bottom of your bike, to make it more "visible" to the magnetic field created by the traffic sensor induction loop. Fairly expensive for small magnets that admittedly don't work all of the time.
There is of course a better solution.
Pick up something like this at any welding supply place or order a 2" Magnetic Ground Block for $3.99 at Harbor Freight:
Remove the Brass grounding bolt and toss it out (or have your ear pierced and bolt it on).
I epoxyed one to the flat cross member that is under the bike, and about even with the leading edge of the battery compartment cover. I tested it out at an intersection in Downtown Oviedo that is known to ignore the presence of a bike.
Bam! The light changed for me!
Some Other Solutions:
-- SilverBack:
I have one light near me that is "iffy" sometimes it trips, sometimes not. When It doesn't, I try a trick a fellow rider passed along: Use the kill switch to stop the bike and then immediately restart it -- seems the current fluctuation of the starter motor is strong enough to trick the trip - which is basically an electronic metal detector, using a current loop to detect the large mass of metal that is a car, but often not a bike. Every time I try this, this and other lights respond.
-- MCN says to get your bike over one of the buried wires and put your kickstand down - works every time according to them.
-- Other folks have used strong magnets from various sources: old speaker magnets, magnets for some motors, magnets from old computer hard drives, even what is called a cow magnet available at farm supply stores (used to trap metal in cows stomachs, I guess -- don't look at me, I just report this stuff!).