Red Light Changer

[gogo]

Try the same thing without the magnets to know for sure.

 

[Alan B]

I've had hit or miss luck with the bike alone depending on where the wheel/bike is placed. It is difficult to tell for certain.

I suspect the best approach is something similar to the kickstarter that failed - a coil and a micro - that picks up the frequency the system is using and then emits a slightly lower frequency which is what happens when a vehicle detunes the in-ground coil. They claim to have a patent, so perhaps this can be researched to provide some info.

The kickstarter design had several problems, for on their coil is perpendicular to the in-ground coil which produces poor coupling. Unfortunately a properly oriented coil is not mechanically ideal. No easy solution.

Magnets will induce some current into the sensing coils, but only when they are moving, and it is at a much lower frequency than the coils are being operated at, so I would not expect the induced signal to make it through the filtering in the sensing system. So magnets don't seem to be a good fit. Better might be a ferrous bar that was very close to the pavement and as long as possible. But an active system could be smaller and lighter than a heavy steel bar, but it must be smart to figure out what frequency to use as the systems are not all the same exact frequency.

 

[cal3thousand]

According to some motorcycle blogs, the best place to line up is ON one of the lines parallel to your direction of travel. Around here, the inductance loops are round. So the best place to line up is on the circumference.

They also stated that a bike's aluminum rims should be enough of a disturbance to activate most sensors. I haven't tested this enough to find out for certain, but I will now that you brought it up. I know of a left turn arrow that definitely won't change unless you are on the sensor that I can use to test.

 

[Alan B]

Unfortunately the settings on each individual unit are adjustable and so they can be sensitive or not. Your rim is probably the best shot, I've seen road bikes open our exit gate with their small racing tires so the rim is close to the ground where my much larger steel rim in the same spot doesn't work perhaps because there is a lot more rubber between the rim and the pavement. Going slow or stopping with the rim in the best spot is a good thing to try.

 

[cal3thousand]

Unfortunately the settings on each individual unit are adjustable and so they can be sensitive or not. Your rim is probably the best shot, I've seen road bikes open our exit gate with their small racing tires so the rim is close to the ground where my much larger steel rim in the same spot doesn't work perhaps because there is a lot more rubber between the rim and the pavement. Going slow or stopping with the rim in the best spot is a good thing to try.

Good to know. Do you think angling your bike closer to horizontal might help change the field enough? Maybe touching one of my pedals down?

 

[r3volved]

How about magnets fitted to the sole of your boot? Just drop a foot

 

[amberwolf]

I merged the new thread about htis with a previous set of merged threads about this topic, so those replying to the new thread may wish to go back and read the previous discussion that's now part of it, as it explores what's being talked about and how and why it works (or doesn't, depending on the situation).

 

[cal3thousand]

I've done some more reading on this topic and it seems like we are not the only forum with much speculation and anecdotal data on the subject.

I did happen to find a document that has more information on the design and use of the inductance loops here at fhwa.dot.gov that has some (to my untrained eye) good information on how cars and, most importantly to us, bicycles affect the sensors.

Of most interest was this diagram showing that bicycles affect the inductance in a different plane (normal) than cars (parallel). I want to do some testing on this and return some more solid data to back up the claim. But basically, a bike should ride along the wire for most effect.

BIKE:

Figure 2-9 illustrates the detection of a bicycle or motorcycle by an inductive loop. These conveyances can be modeled as a vertical conducting object relative to the plane of the loop. When the cycle travels along the loop wire, eddy currents are induced in the conducting wheel rims and frame. When the cycle is directly over the loop wire, coupling between the inductive loop and the cycle is maximized.

CAR:

A vehicle undercarriage, on the other hand, is a horizontal target. As shown in Figure 2-10, the undercarriage is modeled as a conducting rectangular plate, whose width is equal to the width of the vehicle and whose length is equal to the length of the vehicle at some average undercarriage height.

A conducting mesh can be used to approximate the electrical characteristics of the continuous plate. When the mesh is symmetrically located over the inductive loop to produce maximum sensitivity, all induced internal mesh currents cancel. This results in a single induced current flowing around the perimeter of the mesh, which is equivalent to a single turn rectangular wire loop or shorted turn. The air core transformer on the right of Figure 2-10 models the coupling between the vehicle undercarriage, as represented by a shorted turn of wire, and the inductive-loop wire.

Maximum vehicle detection sensitivity is produced by a shorted turn at minimum distance from the loop wires. Consequently, the ideal inductive-loop detector has a shape that approximates the vehicle's periphery. That is, a 6- x 6-ft (1.8- x 1.8-m) square loop would be preferable to one the size of a vehicle's engine.

Because of undercarriage height, high-bed trucks are difficult to detect. Detection of these vehicles is maximized when the width of the loop is equal to the width of the truck, lane width permitting. The length of the loop should not be less than its width to avoid a loss in sensitivity.

 

[Alan B]

Looks like this is now part of 3-4 threads that have been joined on this topic.

The best info in the older threads here was the thought of using mu-metal to affect the pickup coil's frequency, and Richard was going to test this, but I saw no results in the thread.

Since I see no mu-metal based products in the marketplace, perhaps we can conclude that it did not work.

I do have a very large magnet which I could try. We have an exit gate at work that doesn't open easily with a bike that would make a good testbed.

 

[The fingers]

http://www.themirt.com/how-it-works.php
Someone on here couldn't hack one like this up? I have a mfgr's demo of something similar but have never tried to use it.
I put my steel toe boot on the loop, but with mixed results. :|

 

[cal3thousand]

http://www.themirt.com/how-it-works.php
Someone on here couldn't hack one like this up? I have a mfgr's demo of something similar but have never tried to use it.
I put my steel toe boot on the loop, but with mixed results. :|

I'm not trying to turn this little hobby into a felony. I'm already illegal from speed. No need for extra attention. I just want the damn lights to recognize!

 

[regmeister]

If you're not triggering the traffic signal, I recommend contacting the authority that is looking after the signals. And if need be, your local politician and bicycle advocacy groups.

New detection technology is available, but simple sometimes makes more sense. They could program recalls, or add a push button on a pole that can be reached readily by a cyclist.

If you're on a bicycle you could always lay it down on the loop. It might pick up the frame. We used to do that with our dirt bikes.

I see Renoe spec'ing 45 degree angle on parallelogram bicycle loops, so I suspect weaving across the loop line would be most effective.

Personally, I will only wait so long before running the light. I'm pretty sure I've never ran a signal unsafely, other than the one's I never saw in time (I'm a tad color blind..).

 

[mikebikerad]

My steel frame e-cargo bike with large steel frame running boards has no problem opening our driveway gate using the sensor from the inside, while our titanium and aluminum frame bikes with less mass have no chance. This further supports the concept everyone is talking about mass and iron/steel.

 

[amberwolf]

My steel frame e-cargo bike with large steel frame running boards has no problem opening our driveway gate using the sensor from the inside, while our titanium and aluminum frame bikes with less mass have no chance. This further supports the concept everyone is talking about mass and iron/steel.

Has nothing directly to do with just mass.

Has everything to do with magnetically reactive metals.

Only has to do with mass in that there usually must be some critical amount of mass of the magnetically reactive metals.

 

[cal3thousand]

Aluminum will do it to if shaped properly and large enough. Firefighters use their ladders (which I presume aren't Ferrous) to get around gates:

http://www.vententersearch.com/induction-loop-trick/

 

[fechter]

The best info in the older threads here was the thought of using mu-metal to affect the pickup coil's frequency, and Richard was going to test this, but I saw no results in the thread.

Since I see no mu-metal based products in the marketplace, perhaps we can conclude that it did not work.

I never found time to test it. I still have the Mu metal sheet.

A strong magnet passed directly over the coil will generate a voltage in the coil that may trigger it even though the magnet material itself doesn't react much with an inductance sensing circuit. I'm thinking a chunk of motor magnet stuck to the shoe you can sweep over the edge of the coil. The faster the magnet's moving, the more voltage it will generate.

Both worth a try.

 

[amberwolf]

Aluminum will do it to if shaped properly and large enough. Firefighters use their ladders (which I presume aren't Ferrous) to get around gates:

http://www.vententersearch.com/induction-loop-trick/

I hadn't heard of that before--I know that I cannot make any of the alloy bikes I have had (even a pretty heavy one that also has aluminum cargo pods and a flat rack of alloy plate with alloy flat plate sides/supports, alloy rims, etc. The only steel on it was the spokes, some nuts/bolts, crank shaft, bearings, small stuff like that.

Sometimes I've had plenty of time, and momentary inclination, to try out things on these sensors, and I've posted the results of those in the various threads about this sort of thing here on ES. But never did lots of experiments with teh alloy bikes directly, since the "obvious" things didn't trigger sensors with them, where it at least sometimes did with steel bikes.

.

 

[gogo]

Found this while looking for 6V bulbs on eBay:
http://www.ebay.com/itm/Green-Light-Stuff-Trigger-Harley-Nickel-plated-/130417589489?


GREEN LIGHT STUFF TRIGGER FOR HARLEY DAVIDSON - NICKEL-PLATED

BK part number: C01000446

Condition: New
Description:

Makes the vehicle more "visible" to traffic signal detectors
Works on motorcycles, scooters, mopeds and bicycles
Simple, safe, legal and effective
Installs in seconds with no wiring
Installation instructions included
The "more effecient" model; nickel-plated

 

[cal3thousand]

Found this while looking for 6V bulbs on eBay:
http://www.ebay.com/itm/Green-Light-Stuff-Trigger-Harley-Nickel-plated-/130417589489?


GREEN LIGHT STUFF TRIGGER FOR HARLEY DAVIDSON - NICKEL-PLATED

BK part number: C01000446

Condition: New
Description:

Makes the vehicle more "visible" to traffic signal detectors
Works on motorcycles, scooters, mopeds and bicycles
Simple, safe, legal and effective
Installs in seconds with no wiring
Installation instructions included
The "more effecient" model; nickel-plated

What's the science behind this one?

 

[amberwolf]

Can't tell from anythign it says in the page but given it's "nickel plating" it is probably just a neodymium magnet with a rubber or plastic mounting block and the ziptie to keep it attached to non-magnetically-reactive vehicles.

If it is a magnet, then liveforphysics' and others' previously posted explanations apply.


Otherwise, I dunno.


Based on the ziptie and some markings from molding I see on the mountblock, I'd guess that thing is no bigger than a typical DD hubmotor magnet.

 

[Voltron]

Here's another product that looks bike friendlier...sorry if I missed it skimming..

 

[Triketech]

The vast majority of loop detectors used at intersections are capacitive systems not inductive so magnets won't do a thing. If you want to trip the sensor its really pretty simple. Pull you wheel up to the sensor wire; most of them are obvious as they are installed after pouring the road surface.

With the wheel perpendicular roll back & forth a few times. If that's not enough to trip it, then nothing you're going to want to haul around on a bike will be enough.

 

[regmeister]

The vast majority of loop detectors used at intersections are capacitive systems.

Please show me some capacitive loop detectors. Afaik they are all induction based.

Not to say there isn't a capacitive factor.

I believe the main application for capacitive detection is in studfinders.

 

[e-beach]

Just ran across this from California Institute of Technology---aka CalTech

http://caltechbikelab.blogspot.com/p/bike-curious.html

How to Trigger A Green Light With Your Bike

Intersections with loop detectors that detect metal can detect bikes as well as cars. Many Pasadena intersections have these loop detectors. However, you have to position your bike wheel in the right position on the loop to trigger the green light. Here are examples of ways to use your bike to trigger the detector to give you a green light:

 

[e-beach]

The CABO jpg above lead me to this...

https://ladotbikeblog.wordpress.com/2010/11/10/anatomy-of-a-bicycle-friendly-street-loop-detectors/

Anatomy of a Bicycle Friendly Street: Loop Detectors

November 10, 2010 by LADOT Bike Blog

We’re back today with another installment of what surely is your favorite bicycle infrastructure series. Last time out we covered Traffic Diverters – the Cadillac of BFS treatments. This week we’ll look at a much smaller, but no less important, treatment in the:
Anatomy of a Bicycle Friendly Street
Loop Detectors

Placing your bicycle correctly makes for a much more enjoyable ride

(Ed Note: Most information on Bicycle Friendly Street treatments come from the Technical Design Handbook in the draft 2010 LA Bike Plan. Though we are happy to present it in bite-sized pieces, we highly recommend you download it yourself and have a good read. You can download the Technical Design Handbook here. For a refresher on what a Bicycle Friendly Street is -sometimes called a Bike Boulevard- you can read our introductory post here.)
http://clkrep.lacity.org/onlinedocs/2010/10-2385-S2_MISC_07-11-11.pdf See loop detector: Page 76

Listed as a “Type 3” treatment for a Bicycle Friendly Street, loop detector symbols sit dead center in the range of street treatments. While we’ll go into the specifics of how loop detector symbols can be utilized in a Bicycle Friendly Street, we should first cover what loop detectors are and how they work.
Changing Lights with Loops

Loop detectors are coils of wire set into the pavement which, after they are electromagnetically triggered, alert traffic lights to change in the direction you are traveling. There’s a good amount of the hard science on the subject, which you can read more about here.

The takeaway is this: putting your bicycle over a loop detector should make the light change faster.

It's not the weight, it's the magnetic field



Interestingly, it’s not the weight of the bicycle that trips the loop detector, it’s the metal in your bicycle interacting with the electricity running through the loop detector. This does mean, unfortunately, that carbon-fiber bicycles may not have enough metal to set off loop detectors. Since 2007, California state law (with the passage of AB 1581) requires all new loop detectors to be sensitive enough to pick up bicycles......snip