traffic light tip
Greg
Peter Noris
http://www.tinyurl.com/yrk8rs
Greg
--
Peter
"Seeing the U.S.A. one brevet at a time"
13 regions and Canada - more to come!
321-794-0500 cell - 352-275-5888 home - Skype me at Peter.F.Noris
RUSA2691
In a nutshell:
Some traffic lights stay red until a car drives up and trips a
magnetic field sensor buried under the road surface.
Bicycles and motorcycles often don't have enough of what it takes to
trip the sensor so the light stays red.
Attaching a small, very powerful magnet to the underside of the cycle
may allow you to cause the light to change in these situations.
jake Kassen
If that works it would be a cool trick. Hard drive magnets might do,
though you'd have to clean off all the metal junk that clings to it
after a while. Right now I just bike over to the crosswalk button if
there is one.
I see a new custom braze on that will be all the rage at next year's
NAHBS...
Jake
lparker54
1. These sensors are adjustable. If you know which entity is responsible
give them a call/email and they should be able to adjust the sensitivity.
Bikes CAN trigger properly adjusted ones. If the scooter, motorcycle and
small car shown in that video don't trigger it . . . Somebody isn't doing
their job properly.
2. I can't remember who has it available, LAW, Adv. Cycling, Bicycling,
Effective Cycling, . . . somebody.. . but there is a very good explanation
of these induction loops, the different types, how they work, and how to
trigger them. There is some difference depending on the type of loop, but
basically if you are right over the loop, especially if you are at one of
the corners, there is enough electrically active mass in a bike to trigger
it. The exception would be if you have CF frame, crank, rims, bars, etc.
but generally Alloy rims and Crank/BB SHOULD trigger the light.
There is one on my commute that didn't trigger. I mentioned it to our school
resource officer, who has been a bike cop. He had been pushing the button
but after we talked about the adjustability he contacted someone and it
works fine now. There is only one other that I have had trouble with, but
it usually works, so I have not hassled anybody.
If anyone is interested enough to find the online explanation, post the
site. I may search for it. Just irritating me not to know.
Larry Parker
----- Original Message -----
From: "Greg" <greg.o...@gmail.com>
To: "randon" <ran...@googlegroups.com>
Sent: Tuesday, March 25, 2008 12:55 AM
Subject: [Randon] traffic light tip
>
> http://www.tinyurl.com/yrk8rs
>
> Greg
> >
lparker54
here are a couple of links. The first is a quick description and includes
the other two links, one of which is very thorough, the other is summary of
it.
http://www.bikecommuters.com/2007/09/28/turning-traffic-lights-green/
http://www.humantransport.org/bicycledriving/library/signals/green.htm
http://www.humantransport.org/bicycledriving/library/signals/detection.htm
And I stumbled on this for any of you in CA (I don't know if this is part of
the Uniform Code or not, so you will have to check on your home state)
California (AB 1581).
"Upon the first placement of a traffic-actuated signal or replacement of the
loop detector of a traffic-actuated signal, the signal would have to be
installed and maintained, to the extent feasible and in conformance with
professional engineering practices, so as to detect lawful bicycle or
motorcycle traffic on the roadway."
http://www.leginfo.ca.gov/pub/07-08/bill/asm/ab_1551-1600/ab_1581_bill_20071008_chaptered.html
I will bow out now. Need to go get some parts to fix hurdles down at the
track. My son and I will be on our '92 Santana Arriva, a STEEL tandem. THAT
will trigger traffic lights!
Larry Parker, in sunny but chilly Cincinnati
Lynne Fitz
DMV site, it suggested that cyclists line up on the invisible line
delineating the "right third" of the loop. Or 1/3 in from the right,
2/3 in from the left. That seems to do it. I also ride steel bikes.
On Mar 25, 8:42 am, "lparker54" <lparke...@Zoomtown.com> wrote:
> Okay, maybe I have a little OCD, or just time on my hands right now, but
> here are a couple of links. The first is a quick description and includes
> the other two links, one of which is very thorough, the other is summary of
> it.
>
> http://www.bikecommuters.com/2007/09/28/turning-traffic-lights-green/
>
> http://www.humantransport.org/bicycledriving/library/signals/green.htm
>
> And I stumbled on this for any of you in CA (I don't know if this is part of
> the Uniform Code or not, so you will have to check on your home state)
>
> California (AB 1581).
>
> "Upon the first placement of a traffic-actuated signal or replacement of the
> loop detector of a traffic-actuated signal, the signal would have to be
> installed and maintained, to the extent feasible and in conformance with
> professional engineering practices, so as to detect lawful bicycle or
> motorcycle traffic on the roadway."
>
> I will bow out now. Need to go get some parts to fix hurdles down at the
> track. My son and I will be on our '92 Santana Arriva, a STEEL tandem. THAT
> will trigger traffic lights!
>
> Larry Parker, in sunny but chilly Cincinnati
>
>
>
> ----- Original Message -----
> From: "Greg" <greg.olmst...@gmail.com>
> To: "randon" <ran...@googlegroups.com>
> Sent: Tuesday, March 25, 2008 12:55 AM
> Subject: [Randon] traffic light tip
>
> >http://www.tinyurl.com/yrk8rs
>
>
> - Show quoted text -
Paul Ries
online hoaxes):
http://message.snopes.com/showthread.php?t=16531
It seems less than clear cut, but ultimately boils
down to confusions over inductance (which I does
involve magnetic fields interacting with electric
ones) versus magnets. I'm an EE and I have a tough
time with this, so it is not suprising that it is
confusing to a lot of people.
Anyway, the guys point that a large chunk of copper
would set one off, while being completely non-magnetic
should be a bit of a clue.
The traffic loops relate to a change of inductance and
small rare-earth metal magnets do not have the
property to change inductance much more than any other
chunk of conductive metal of about the same size. I
guess I read in wikipedia that ferromagnetic materials
do changes some of the properties of an inductor
(noteably the Q), but I suspect it would need to be a
LOT of this material, maybe a few pounds.
From what this says (referenced in the above snopes
article and written by a manufacturer of these
devices):
http://marshproducts.com/pdf/Inductive%20Loop%20Write%20up.pdf
what really matters is surface area of conductive
metal and closeness to the loop. The surface area
that matters is part parallel to the loop (like the
bottom a car). This explains why bikes are at a
disadvantage.
Save your money. I guess the point about a steel or
other conductive metal bike is certainly valid, though
some lights are adjusted to be less sensitive and just
won't change. For those it is recommended to call the
city and complain rather than spending your energy on
taping things to your bike.
-Paul
Peter Noris
In most cases I've found that stopping with my (steel) bike crossing the corner of the pavement cut-outs (if it's a retrofitted signal) will trigger the light. Worst case, get off and lay the bike down closer momentarily.
DennisTheBald
across the ends would be the best "help", other than knowing where the
field was. There maybe a cut in the concrete that discloses the
location of the coil that generates the field, but figuring out the
shape of the actual field is a bit trickier.
Mark Wooldridge
one side or the other of the rectangular loops, or put
your bike on the center of the crossing cuts if it's a
figure 8 loop.
The traffic engineer can tinker with the sensitivity,
but he's trading off increased sensitivity that may
give a false detection from a car/truck in an adjacent
lane vs detecting a bike. He may be able to adjust
the setting to work for both issues.
My current favorite type is video detection. They're
typically aimed towards the center of the lane,
though, so if you see them you may need to move to the
middle of the lane as you approach the stop line. Of
course, that's where the cars are so be careful. You
can tell if this is the type of detection by seeing
the little cameras aimed at each approach. Don't feel
self-conscious, the video feed usually just goes to
the control cabinet and the signal controller.
Usually. And you can't generally rotate the angle of
view remotely, anyway, on this type of mount.
Our guys sometimes use a stop sign face (24") held
flat to the road to check the detection from a loop
detector, so you could always just carry one of those.
Mark "not a _traffic_ engineer, although I know quite
a few" W.
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CRWGPSGUY
I am a EE... And magnets shouldn't do doolie squat. And that goes double for
the vision system ones.
> I suspect that a coil of wire with...
The rims of your wheels are a very nice shorted coil.
... One of the ways of testing a loop is to create a loop about
2 feet in diameter with several turns of wire (connecting the ends) and
placing the test wire in the middle of the traffic loop...
I would like to know what frequency these things use so I can build a tuned
circuit for it, or a active circuit that could generate a "I'm here". This
should be much smaller then a huge slab of metal. I encounter only a few of
these systems on the back roads of New England ( where you are lucky if
there is a stop sign ) so my need hasn't been all that pressing.
...If you have a metal frame, another tactic that may work is to lay the
bicycle down horizontally inside the loop...
Proximity to the field is also helpful, see
http://www.bikexprt.com/bicycle/actuator.htm
I would suggest standing on one foot an leaning the bike at a 45. This would
get you ~70% of laying it down would get you and you still are 'on the bike'
ready to go. But I haven't ever found this to work better then not.
As usual, Your detection may very...
NER, Paul H. design engineer of industrial sensors.
Charles Coldwell
>
>
> I would like to know what frequency these things use so I can build a tuned
> circuit for it, or a active circuit that could generate a "I'm here".
If I had to guess, I would say 60 Hz in the US and Canada, and 25 Hz
in Europe. The only reason to use a frequency higher than the mains
frequency would be in order to make the coils smaller, but since they
want them big, why bother?
Chip
--
Charles M. Coldwell, W1CMC
"Turn on, log in, tune out"
Somerville, Massachusetts, New England
lightman
I am not convinced laying the bike down does any good at all.
As mentioned in other postings, the important thing is to place the
wheel over the line in the pavement in the same direction that the
loop wire is running. It does not matter if the wheel is steel or
alloy but it must be some kind of conductive metal. The frame has
little effect compared to the rim due to the fact that the rim can be
placed so much closer to the loop wire. In order for the frame to
contribute to tripping the detector, a frame member would have to be
within an inch or two of the roadway.
Some other tips: The 'sweet spot' is within two inches of the loop
wire. This is where the detector will me most responsive to
tripping. The sensitivity is also more sensitive inside the loop.
Therefore the sensitivity is greater 2 inches inside the loop than it
is 2 inches outside of the loop.