soho2009

Is there anyway for a bike rider to trigger an inground sensor at a 4 way stop light? I can visiually see the frame of the sensing equipment and tried standing inside, outside, and across the frame.

What works is waiting for a car to enter the frame or jumping off the bike and walking 10 yards to push the button on the walkway. Course that walkway isnt a walkway, just grass. The other alternative is to run the red when opposing traffic has a green but my direction stays red.

Maybe a note to the local light authorities asking them to sync up the two directions wouldnt hurt.

Pain in the butt on the morning commute, but, that intersection is a pretty good crossing street relative to my other choices.

lucasgo

I know I've read about this recently, but don't feel like searching for the thread. Basically, there are a few types of sensors. Is it just a rectangle perimeter, or one rectangle with a center line, or an octagon? If the first, then your best bet is to stop on the left line and lean your bike over toward the center. If the second, then stop on the center line and tip your bike to either side. The third theoretically works where ever you stop as it is much more sensitive. Of course, this works best for steel frames, then aluminum. I'm not sure about carbon. I've gotten sensors to work without tipping my steel frame bike. If you notice these don't work, then contact the town highway folks and ask them to turn up the sensitivity at your intersection.

Or just run the red.

iforgotmename

I often do concrete restoration in parking garages and we use a piece of steel to open the gate. I'm not sure if the light sensors are magnetic and carrying a piece of steel would be a pain Just run the red if it's safe. ^^^^^posted at same time oops.

soho2009

Appreciate the comments and will give them a try. Its a rectangle (or two rectangles) with the stars representing the frame and the underscore lines spaceholders:


_**************_
*______________*
*______________*
_**************_
*______________*
*______________*
*______________*
*______________*
*______________*
*______________*
*______________*
*______________*
*______________*
_**************_

soho2009

mmm, the bike is aluminum so thats not helping.

Shimagnolo

We had this discussion recently.
It was pointed out that the sensors utilize eddy currents, so any conductive metal will work.

https://www.humantransport.org/bicycl.../detection.htm

soho2009

Thank you for the links. I was trying to put the bike across the frame rather than orientating the rims along the frame edge. Will try right edge first. Left edge is a bit too close to unexpecting traffic.

https://www.humantransport.org/bicycl...nals/green.htm

lucasgo

Wait, are you riding L->R or down->up? The diagram makes sense to me if you are going left to right (or right to left). There is basically a double-set of sensor at the middle line of asterisks, making it more sensitive. Is the center line offset to the side in reality, or are they the same distance? If it is offset, then tip your bike toward the closer line (see your copied diagram, bike is 'B', tip toward 'T'). Aluminum does work, btw. My road bike is Al, and I've set them off by tipping.

If your diagram is read from bottom to top, I'd say to stop on either side right where the center line intersects, then tip toward the center. Using the diagram, stop with the bike as 'b', and tip the bike toward 't'.






_**************_
*______________*
bt_____TTT____tb
bt*****BBB****tb
bt____________tb
*______________*
*______________*
*______________*
*______________*
*______________*
*______________*
*______________*
*______________*
_**************_

EDIT: Yeah! That was the website!

thestoutdog

I seem to recall someone mentioning rare earth magnets. I have know idea if this works though.

X-LinkedRider

Most traffic scales and cable triggers have a 500lb minimum threshold. I would say good luck but you'll only be wasting your time short of riding over to the light and hitting the button.

Shimagnolo

And if that button is a "placebo button", that will be a waste of time as well.
A number of the buttons around here which used to actually be active have been converted to
placebo buttons, and no longer do a d*amned thing, even if there is no traffic whatsoever.

soho2009

The view is from above with the intersection ahead like this:


------Intersection Is located HERE!------------------


_**************_
*______________*
bt_____TTT____tb
bt*****BBB****tb
bt____________tb
*______________*
*______________*
*______________*
*______________*
*______________*
*______________*
*______________*
*______________*
_**************_

I twice now, tried to trip it by going across the center line where you placed the capitalized T's and B's, not because I knew what I was doing but, it seemed logical. I was placing the bike perpindicular with the center line rather than parallel never thinking the rims would make a difference.

It doesnt happen every day, though. Sometimes there is a car that comes up during the wait that trips the senser.

The button could be a placebo. I went for it twice and both times I was so busy getting off the bike, then back on, pushing off the grass, then off the curb and shooting for the light change (its a very short light) that the angle was too severe to see if the my light had changed and relyed, instead, on seeing cars coming from the opposite direction to confirm. Not something safe, in its present form, and pretty dangerous in less than perfect weather.

Kilted Commuter

Consider attaching a rare-earth magnet to the underside of your bottom bracket, get a strong one, 20# or so, glue it, tape it, drill it and rivet, whatever your preference. When arriving at the sensor, be sure to stop with the magnet directly above one of the cables.
Or follow this instructable: https://www.instructables.com/id/Traf...for-your-Bike/
Or buy one of these: https://www.greenlightstuff.com/trigger.html

moralleper

I have found good success with the rectangle sensors to ride up to the right side of the box with both wheels lined up with the line. This seems to work every time.

cyccommute 

Magnets do nothing to help with triggering stoplights. It's been covered before. The magnetic field of the magnet is too small...even with a strong magnet...to have any effect on the induction loop. Your statement above of "...be sure to stop with the magnet directly above one of the cables", will do more to trigger the sensor than even dozens of magnets would. Your bike wheels are closer and have a better interaction with the sensor. Look at Steve Goodridge's link given above for an explanation.

cyccommute 

Follow the link above to Steve Goodridge's page. Even before I read his paper, I was triggering lights on a very regular basis simply by proper location when riding over the wires buried in the pavement. His paper is just a clear explanation of why this works.

I can trigger just about any light in the Denver Metro area...if I can find the wires. Finding them is often the hardest part. Repaving buries them and makes them harder to find.

Motion sensors are more difficult to trigger. Unfortunately, they are taking over for buried loops.

cyccommute 

That works well too. I think part of the reason that the right side works well is that the wire is doubled over on itself at the right corner near where the wire leaves the loop. Doubled wire increases sensitivity.

MMACH 5

Perhaps a rare earth magnet in the sole of your shoe? I haven't tried this. I'm just curious.

woodway

Stop with your front wheel directly on top of the upper right or upper left corner of the rectangle. If your back wheel is also on top of the rectabgle, that will help as these are inductive loops that are "de-tuned" by the presence of metal, so the more metal the better.

A rare earth magnet is not going to do anything unless it's a honking big magnet.

The sensitivity of the loop can be adjusted, and some may not be adjusted sensitive enough to detect a bicycle. In that case, try calling the road department in the jurisdiction where the light is located and ask them to readjust the light. I've watched the local department adjust the light sensitivity by using a bicycle wheel!

The loops around here have a small X painted on them where you are suppoed to place your front wheel which makes it easy to trigger them.

cyccommute 

I doubt it would do much. Too small a target. The loop's switching mechanism may just see it as a background spike. This part of the Goodridge article is probably the most applicable

ItsJustMe

Stoplight sensors do not measure weight. They're metal detectors. They can usually be triggered by a bicycle, IF you can get your wheel rim right over the detector loop. Laying the bike down on its side helps too.

Since it's magnetic and in a plane, it follows the inverse square law, so a bike wheel 1" from the sensor has 100x the influence as it would if it were 10" off the ground.

prathmann

The suggestions to place your bike along one of the lines of the sensor are good - and I've found that laying the bike partly on its side helps (I still stay clipped-in). But it sounds like this light is still unresponsive, so contact the local traffic authorities and report that the sensor isn't detecting your bike. In most cases they can make a simple adjustment to increase the sensitivity enough to detect a bicycle.

dipy911

Only 1 of the stoplights on my way in to work sees me, and it sees me about 15 feet from the light. The rest of the lights are treated as four-way stops. One busy intersection I use the ped button, which works, which causes the light to stay green for me way much long that I need to get though and causes the cars going the other direction to wait longer than normal.

So I guess the answer is all of the above. You could also wait for a car to eventually come and trip the sensor too.

cyccommute 

I was going to say that

By the way, the inverse square law is the reason a magnet...even a strong one...mounted on the downtube of the bike has little to no influence on the magnetic field of the loop sensor.

seenoweevil

This seems to work well for me also. I haven't had any major delays since reading about the technique a year or so ago.