Topic: Bike Won't Trip Stoplight

[gerhed]

My favorite tour starts out on a 4 lane for a little high speed work and then I
exit to the right and up over the top of the 4 lane to the left where there is
a stoplight where I want to turn left for some 2 lane twisties finally ending up
at a country store/greasy spoon where I hope to impress young ladies with my
bike and/or natural charm.
The problem is the stop light won't turn green unless a car shows up
--which doesn't always happen. So I generally run the thing, but eventually I'll probably
 run afoul of the law.
What's the answer?
Can I hammer on the asphalt or maybe deGauss the sensor?

[SD750F]

gerhed,

A very typical problem for motorcycles. Especially when the idiots who "set" the sensitivity of the road sensor too high. The way it works is there is a wire coil installed under the octagonal cut in the road. This is nothing more than a large metal detector. And metallic interference to the resonance of the coil is detected and signals the light change. There are some manufactured devices that bolt to the underside of your frame that are suppose to trigger the sensor but I have no personal experience with them. And you could call your local municipality traffic division and report the light as being not sensitive enough and wait 100 years for them to send someone out... If I knew the general resonance frequency of the sensor coil, I could design an active device that should work better than the non-active devices available. Just a thought.

Scott

[gerhed]

So the thing is looking for a substantial piece of metal--not down force?

[Bodi]

Yes, it detects metal and weight is not an issue - you could set a few tons of plastic on the sensor and not get the light to change.
The devices sold to make bikes trip them are just relatively powerful bar magnets with a plastic coating and a mounting clamp that you attach to the bottom of the machine. I haven't tried one but I do have some magnets that I hope to carry out on the road some quiet night and test.

[BobbyR]

Yes there was some people selling magnets to help you trip them. There are put down the kickstand ideas. Where I live you can count on a car tripping it for you.

[cleveland]

I've been considering these.  Anyone actually put them on their bike?

http://cgi.ebay.com/ebaymotors/SIGNAL-SORCERER-TRIP-TRAFFIC-LIGHTS-FREE-SHIPPING_W0QQitemZ190096886021QQcategoryZ10064QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

[csendker]

The PO strapped one of those magenet things on the bottom of my bike.  It took a while to figure out what the heck it was.  I'll roll up to a light so the magnet is directly over the sensor cut....and wait.  And wait.  And wiat some more.  There's some lights that I think a Semi would have a tough time tripping.  And being in the left turn lane makes a right hand turn and subsequent u-y oh so fun.  I'm not sold that the magnets actually do anything.

[Andoo]

Led Boots 

[SD750F]

What I have read and it makes sense, is that you do not drive through the center of the coil, but along one of the side coils, with magnet or not. And this is also the best place to lower your kick stand. This is the most sensitive location to trip the light.

Scott

[ProTeal55]

When I worked at the V-Twin shop we sold TONS of those magnetic light tripper things.
I heard both good & bad about them so who knows what the real scoop is...?

[clarkjh]

Another trigger for the lights are to flick your headlight at it before you get to the stop line, most have sensors to pick up flashing lights.

James

[BobbyR]

I wonder if the sensor is tripped by metal mass or surface area. I wonder if some thin sheet metal underneath the bike would help. It seems clear the magnets work so so.

[Gordon]

I've had a lot of success with stopping the bike with the engine directly over any spot in the sensor where there are a few wires close together, usually at one of the corners.  This gets the steel crankshaft and transmission gears over the most sensitive section of the sensor. 

[Steve F]

Another trigger for the lights are to flick your headlight at it before you get to the stop line, most have sensors to pick up flashing lights.

James

You're referring to the "OPTICOM" sensor.  Unless you can flash your lights at PRECISELY 10Hz, it won't work.  But then again, there are people making infrared  L.E.D. strobes clocked to flash at 10Hz......    Infrared is nice as it's not visible to the naked eye, and is easy to conceal and is picked up by the device.  Be warned, private ownership and/or use of such a device carries a stiff penalty.

[nickjtc]

If you use the same interesection on a regular basis and the lights will not trip for you call the local municipal or state authorities and have them de-sensitise the system. Up hereabouts that produces the required effect, since everyone wants traffic to flow as efficiently as possible.

[DammitDan]

I went out and bought a magnet (since I could never get ANY left turn signals to trip for my bike) and it works on SOME lights now.  Others I have to pray a car comes up behind me.  And sometimes I think placement of the bike makes a difference.

I've never tried the kickstand thing, I'll have to check it out.

[burmashave]

...Up hereabouts that produces the required effect, since everyone wants traffic to flow as efficiently as possible.

Man, Nick, that must be a west coast thing.  Traffic control on the east coast seems to be designed to stymie all movement.  :-(

One tip I got is that if there is a bike lane, get near it or on it.  The magnetic sensors in a bike lane have to be sensitive enough to be tripped by a bicycle.  Of course, this only works where there is a bike lane.  I try to stop close to the top of a metal strip, but  I hadn't heard about using the center stand. 

I would guess that it might help to move the bike forward or back a bit if you don't immediately trip the signal.  We have a signal here that is difficult to trip with a car.  When it doesn't trip immediately, I roll the car back a foot or so, and that does the trick. 

[cb650]

Sometimes it just the rider.   A light by my G/F house she cant trip on her sporster.   But I can get it to trip if its been red for awhile on my 360.   But another light I sometimes come across wont trip for $hit.  Usually run it.




                                   Terry

[Rushoid]

We use loop detectors like this http://www.emxinc.com/vehicle-loop-detector-d-tek-box.html in some of our car wash doors to trigger opening/closing. I don't know what traffic signals use but it's probably similar. We have problems with them failing to read tall vehicles because the sensitivity is a percentage of the circumference of the loop. So if you have a 2' pad, "10" would read 2' up from the ground, "5" would read 1' up, etc. I've always tested them by waving my tool box a foot or so above them. Also, sometimes my steel-toe boots would trigger it.

I've had problems sitting at a light, behind the white line, where I wait forever. One night I figured I'd try crossing the line because I saw another loop pad beyond it. The light tripped within 2 seconds! I haven't been stuck since.