Traffic light tripper

[JohnCh]

There are a few intersections in my area that have insensitive traffic sensors embedded in the left turn lanes. If I am the only car there, the Westfield doesn’t have enough ferrous material to trigger the sensor and turn the light green. I’ve heard about some inexpensive devices for motorcycles that are designed to counter this deficiency by using a powerful magnet attached to the bottom of the bike. Does anyone have any experience with these devices? Do they work? Any interference problems with the electrical system? The manufacturers all claim their devices are “engineered” so they don’t cause problems in that area, but the fact that they even mention this makes me a bit nervous.

 

Thanks,

John

[MHKflyer52]

Hi John,

 

We have the same thing here in the local area so I have one of these sitting on the floor up against the frame and it seems to work very well. Sometimes I have to reach down and pick it up and wave it close to the sensor wire area that is embedded in the street surface especially if the road has had a seal cap applied to it without redoing the sensors.

 

http://www.onlinesciencemall.com/Shop/Control/Product/fp/SFV/30852/vpid/1988887/vpcsid/0/rid/126318

 

The Ultimate Heavy-Duty Cow Magnet!

http://a763.g.akamai.net/7/763/1644/4/app.infopia.com/img/image/fp/VPID/1988887/size/250

 

Now stop laughing as I know it seems dumb but it dose work.

Edited February 4, 2010 by MHKflyer52
Added Photo of Magnet

[scannon]

I hear taping a couple of those cow magnets to your fuel line will double your gas mileage. Another one on the oil filter and your engine will last forever.

 

Both were urban legends long before the internet became available to all of us.

[JohnCh]

Thanks Martin. Skip, if I attach the magnet to my oil filter which is located really low in the chassis, will it solve the traffic light issue and make my engine last forever?

 

-John

[slomove]

I also heard the magnets are snake oil but supposedly there are expensive devices with active electronics that pick up and manipulate the RF field of the loops. But, until I see it work I stay suspicious.

 

I am not sure if the loops work on changes of inductance or changes of field losses by the eddie currents induced in the metal mass above. But I just can not see how a small stationary permanent magnet, no matter how strong, can be detected by such a loop.

[scannon]

Thanks Martin. Skip, if I attach the magnet to my oil filter which is located really low in the chassis, will it solve the traffic light issue and make my engine last forever?

 

-John

 

Garronteeed! How may would you like to buy today?

[JohnCh]

Gee Skip, I don't know. How many can I get for just three easy payments of $20/mo?

 

Gert, thanks for the insight. It seems a little odd to me too, but these things are over my head. I'll do some research on motorcycle forums to see if I can locate any user reviews.

 

-John

[Alaskossie]

When I first saw the title, "Traffic light tripper," I thought maybe you were talking about those devices that fire trucks and police cars use to send a signal to a traffic light to instantly turn it green (and the intersecting street red). Some of these have fallen into "private" hands, I understand, where they might prove to be a very useful time-saver....

 

Our local government passed an ordinance a year ago, making their use illegal except for emergency vehicles. Darn!

[slomove]

more info

 

So, it looks like standing over the wire in the asphalt groove may give you better response than in the middle of the loop.

 

Or you can attach a very large and massive aluminum skid plate to the the car. That would do it ;-)

 

Gert

[JohnCh]

Thanks Gert, interesting article. Sounds like my best option is to upgrade to 19" wheels

 

-J0hn

[MHKflyer52]

Have to say the article is a good one that Gert posted but I am still going to cary my COW MAG as it has worked for me and besides it can be used as a weapon if necessary kind of like the biker that caries a small ballpeen hammer on their cycle if you know what I mean, besides it gives me pice of mind and something to do when stuck at a traffic light with no traffic in site....LOL at myself...

[BruceBowker]

Never heard of trippers. Seems rather poor engineering considering how many motorcycles are out there.

[wmontoya]

the "hottest-spot" for pick-up on common in-ground wire-loop sensors (usually layed out in a square or rectangular pattern) is just slightly inward from any corner... that's where you want to place your largest iron hunk (engine). this from motorcycle experience & electromagnetic theory.

 

never found a strong-enough-to-help magnet that was also light-enough-to-realistically-carry on a bike. two 1"x1"x1/2" NIB (rare earth) magnets didn't do much to help trigger sensors on a med-sized bike.

 

the uber-cow-magnet torpedo thing is pretty funny... especially in a Seven... but if it works, huzzah!!

 

regards... WM

[JohnCh]

the "hottest-spot" for pick-up on common in-ground wire-loop sensors (usually layed out in a square or rectangular pattern) is just slightly inward from any corner... that's where you want to place your largest iron hunk (engine). this from motorcycle experience & electromagnetic theory.

I feel like this is some kind of warped IQ test. Our sensors are laid out in an oval pattern...

 

-John

[wmontoya]

... well, all i can say is check out the link that was posted earlier by Gert(?) to the paper "Detection of Bicycles by Quadrupole Loops at Demand-Actuated Traffic Signals"

(http://www.humantransport.org/bicycledriving/library/signals/detection.htm)...

 

that info's consistent w/ what i've read for the typical in-ground sensor and it shows either squares or rectangles w/ "cut corners"... but the shape is more squared off than rounded/oval (given the normal size of in-ground loop sensors).

 

i know that placing a motorcycle's engine near the hot-spot zones does helps trip traffic light sensors in many cases... not all, but many. a few on my commute don't trip w/ a med-sized bike no matter where it's placed... and those fortunately always trip w/ my 7.

 

further observations:

- never tried the trick w/ a bicycle, but the explanation given in the paper isn't functionally inconsistent either... i know places where riding a motorcycle slowly along the left or right sensor line as one approches a red signal often helps speed up the tripping in three specific intersections.

- one intersection will trip for a motorcycle only when no cars are around... if cars are around (moving or stopped) the bike will never trip it (requiring getting off and pushing the predestrian "walk" button).