Traffic Loop Sensor Trigger For Bikes

From the "More Stuff on a Bicycle Is Better," Dept.

http://gizmodo.com/5079430/traffic-l...e-green-lights
--
Mike "Rocket J Squirrel"
Bend, Oregon

On Sun, 09 Nov 2008 08:11:58 -0800, Mike Rocket J Squirrel
wrote:

From the "More Stuff on a Bicycle Is Better," Dept.

http://gizmodo.com/5079430/traffic-l...e-green-lights

Dear Mike,

On a faintly related note of gadgetry . . .
http://www.wooljersey.com/gallery/v/...c-gaz.JPG.html

Cheers,

Carl Fogel

On 11/9/2008 11:57 PM wrote:

On Sun, 09 Nov 2008 08:11:58 -0800, Mike Rocket J Squirrel
wrote:

From the "More Stuff on a Bicycle Is Better," Dept.

http://gizmodo.com/5079430/traffic-l...e-green-lights

Dear Mike,

On a faintly related note of gadgetry . . .
http://www.wooljersey.com/gallery/v/...c-gaz.JPG.html


Sigh. All I need is a budget and the requisite personality disorder to
totally get into collecting such fine niche products.

--
Mike "Rocket J Squirrel"
Bend, Oregon

On Nov 9, 11:11*am, Mike Rocket J Squirrel
wrote:
*From the "More Stuff on a Bicycle Is Better," Dept.

http://gizmodo.com/5079430/traffic-l...for-bikes-gets...
--
Mike "Rocket J Squirrel"
Bend, Oregon

I wonder how this does on the sensors that are mounted to the light
and not embedded in the pavement? On motorcycles, a common way to
trip the sensor if your bike doesn't have enough steel facing the
light is to angle the bike a bit and put your kickstand down. I'm
guessing a bicycle kickstand still doesn't contain enough steel.
Hm.. also makes me wonder if there are actually sensors in the light,
or if the angle the bike part is pointless and all lowering the
kickstand does is get the steel closer to the pavement. Eh, either
way, when riding a mostly aluminum crotch rocket, the kick stand trick
works. I find when on a bicycle the "running the light" trick is good
enough. I can think of far more practical ways than this to add that
kind of weight to my bike. An espresso machine comes to mind right
out of the gate. So does a handlebar mounted harpoon gun. Perhaps a
tall skinny vanilla barista. Point being, there are better ways to
add a couple pounds to your bike. At least in my opinion.

On Nov 10, 8:54*am, " wrote:
On Nov 9, 11:11*am, Mike Rocket J Squirrel

wrote:
*From the "More Stuff on a Bicycle Is Better," Dept.

http://gizmodo.com/5079430/traffic-l...for-bikes-gets...
--
Mike "Rocket J Squirrel"
Bend, Oregon

I wonder how this does on the sensors that are mounted to the light
and not embedded in the pavement?

Some places have gone to optical/IR sensors instead of embedded
loops. These should detect motorcycles and bicycles.

On motorcycles, a common way to
trip the sensor if your bike doesn't have enough steel facing the
light is to angle the bike a bit and put your kickstand down. *I'm
guessing a bicycle kickstand still doesn't contain enough steel.

No steel is required - the loop sensors are metal detectors which use
the same principle as the detectors people use at the beach to find
coins and jewelry. Anything that conducts electricity will trigger
the sensor. I frequently put my aluminum bike down to get the rims
and frame closer to the sensor and thereby trigger the light. This
works almost all the time - and I'm sure my Cannondale has much less
metal than your motorcycle.

BTW, the sensors are adjustable and can be set so they will detect
bicycles. If you have one that fails to do so then complain to the
local traffic engineering department and have them readjust the
sensitivity.

Hm.. *also makes me wonder if there are actually sensors in the light,
or if the angle the bike part is pointless and all lowering the
kickstand does is get the steel closer to the pavement. *Eh, either
way, when riding a mostly aluminum crotch rocket, the kick stand trick
works. *I find when on a bicycle the "running the light" trick is good
enough. *I can think of far more practical ways than this to add that
kind of weight to my bike. *An espresso machine comes to mind right
out of the gate. *So does a handlebar mounted harpoon gun. *Perhaps a
tall skinny vanilla barista. *Point being, there are better ways to
add a couple pounds to your bike. *At least in my opinion.

On Nov 10, 12:22*pm, peter wrote:
On Nov 10, 8:54*am, " wrote:

On Nov 9, 11:11*am, Mike Rocket J Squirrel

wrote:
*From the "More Stuff on a Bicycle Is Better," Dept.

http://gizmodo.com/5079430/traffic-l...for-bikes-gets....
--
Mike "Rocket J Squirrel"
Bend, Oregon

I wonder how this does on the sensors that are mounted to the light
and not embedded in the pavement?

Some places have gone to optical/IR sensors instead of embedded
loops. *These should detect motorcycles and bicycles.

On motorcycles, a common way to
trip the sensor if your bike doesn't have enough steel facing the
light is to angle the bike a bit and put your kickstand down. *I'm
guessing a bicycle kickstand still doesn't contain enough steel.

No steel is required - the loop sensors are metal detectors which use
the same principle as the detectors people use at the beach to find
coins and jewelry. *Anything that conducts electricity will trigger
the sensor. *I frequently put my aluminum bike down to get the rims
and frame closer to the sensor and thereby trigger the light. *This
works almost all the time - and I'm sure my Cannondale has much less
metal than your motorcycle.

BTW, the sensors are adjustable and can be set so they will detect
bicycles. *If you have one that fails to do so then complain to the
local traffic engineering department and have them readjust the
sensitivity.



Hm.. *also makes me wonder if there are actually sensors in the light,
or if the angle the bike part is pointless and all lowering the
kickstand does is get the steel closer to the pavement. *Eh, either
way, when riding a mostly aluminum crotch rocket, the kick stand trick
works. *I find when on a bicycle the "running the light" trick is good
enough. *I can think of far more practical ways than this to add that
kind of weight to my bike. *An espresso machine comes to mind right
out of the gate. *So does a handlebar mounted harpoon gun. *Perhaps a
tall skinny vanilla barista. *Point being, there are better ways to
add a couple pounds to your bike. *At least in my opinion.- Hide quoted text -

- Show quoted text -

Interesting. I was told to "point the kickstand at the light" by my
instructor when I learned that trick. That part is probably useless.
Dropping the stand does work though, I've sat through a couple cycles
and then dropped the stand and triggered the light in the past. Must
just be moving the stand closer to the sensor. I traded the crotch
rocket for a dirt bike, so I won't be finding out anytime soon. It's
my understanding steel framed bikes don't have that issue, but mostly
aluminum bikes, usually crotch rockets, do. Makes sense, since I
never had the problem on my old steel framed Ninja, but my much newer
aluminum framed R6 never seemed to trip a light without dropping the
stand. The stand and the bolts might have been the only steel on that
bike though.

On Nov 10, 12:41*pm, " wrote:

Interesting. *I was told to "point the kickstand at the light" by my
instructor when I learned that trick. *That part is probably useless.
Dropping the stand does work though, I've sat through a couple cycles
and then dropped the stand and triggered the light in the past. *Must
just be moving the stand closer to the sensor. *I traded the crotch
rocket for a dirt bike, so I won't be finding out anytime soon. *It's
my understanding steel framed bikes don't have that issue, but mostly
aluminum bikes, usually crotch rockets, do. *Makes sense, since I
never had the problem on my old steel framed Ninja, but my much newer
aluminum framed R6 never seemed to trip a light without dropping the
stand. *The stand and the bolts might have been the only steel on that
bike though.

My ancient (1972) BMW R75/5 has plenty of steel, but it's still not
detected by certain traffic light sensors.

Peter was correct. The most common sensor is functionally equivalent
to a metal detector with the coil buried in the pavement. It's
probably less sensitive to aluminum than to steel, though. Inductive
proximity sensors used with automated machinery work on the same
principle, and the rough rule of thumb is that they're about three
times better detecting steel than aluminum.

Still, the traffic engineers should have them set to detect all legal
vehicles. Usually a phone call will get a crew out to adjust it.

Sometimes they don't like to set them high enough to detect a bicycle,
because the detecting field spills over into the next lane, and gives
a false positive when there's a car in the adjacent lane.

There are fixes for that problem. One of the best is a change in the
shape and wiring of that detection loop. But most traffic engineers
are really "car traffic" engineers. Bikes (motorized or not) are off
their radar.

Don't tell them about the false positives. Just say it's dangerous
when it doesn't detect your vehicle. They'll probably turn the
adjusting screw a little, and it will be fine.

- Frank Krygowski

On 11/10/2008 8:54 AM wrote:

On Nov 9, 11:11 am, Mike Rocket J Squirrel
wrote:
From the "More Stuff on a Bicycle Is Better," Dept.

http://gizmodo.com/5079430/traffic-l...for-bikes-gets...
--
Mike "Rocket J Squirrel"
Bend, Oregon

I wonder how this does on the sensors that are mounted to the light
and not embedded in the pavement?

There was a nasty intersection in Carlsbad, CA, where I lived for several
years. The bike lane ended on the right hand side of the right turn only
lane, without even a crosswalk across the street at that point. I got the
city to re-stripe the road leading to the intersection so that the bike
lane "moved" over to between the right-only lane and the straight-ahead lane.

The next part was dealing with the traffic sensor. The buried loops didn't
pick up bikes - the issue the gadget above claims to fix.

Because the intersection was too unsafe to try a red-light dash (many
lanes to cross, uphill, fast traffic, no line of sight far enough to see
approaching cars) I usually had to wait for cars to come up from behind to
get a green.

I contacted the city and they arranged for video sensors atop the traffic
lights, this being part of a general upgrade that was going on around the
town anyway, they just moved this intersection to the front of the list.

The video sensor worked brilliantly for a few months then stopped seeing
bikes. I contacted the city who contacted the contractor and he checked it
and said it should be working fine. I said it wasn't and volunteered to
meet the guy and demonstrate.

We met up and he opened up the cabinet. Inside was a funky black and white
TV with views of the four directions of the intersection. Pressing a
button on one of rack-mounted pieces of equipment caused white-outlined
boxes to appear on the video display, outlining the lanes and areas of
interest. The lanes I had been riding the bike into were clearly outlined,
but when I tried a test, the equipment didn't trigger though I was visible
on the monitor.

Bad connection at the video camera, he suspected. So he set up his
cherry-picker and replaced the cable connector at the rear of the camera
and we tried again. This time the equipment triggered. But then
untriggered once I paused at the limit line. He said that the system looks
for movement and contrast in the image to determine if something is there,
but the bikes contrasty bits were apparently too small to be of interest
so the system decided that the movement was a false positive and didn't
start the process to change the light.

He re-programmed the intersection with a "lockout" so that once triggered
it still scheduled a light change whether or not it stopped seeing me.

From that point on, the intersection worked perfectly.
--
Mike "Rocket J Squirrel"
Bend, Oregon

In article
,
" wrote:

On Nov 9, 11:11*am, Mike Rocket J Squirrel
wrote:
*From the "More Stuff on a Bicycle Is Better," Dept.

http://gizmodo.com/5079430/traffic-l...for-bikes-gets...

I wonder how this does on the sensors that are mounted to the light
and not embedded in the pavement? On motorcycles, a common way to
trip the sensor if your bike doesn't have enough steel facing the
light is to angle the bike a bit and put your kickstand down. I'm
guessing a bicycle kickstand still doesn't contain enough steel.

It need not be steel, only a conductive body that will have
eddy currents induced in it by the inductive loop in the pavement.

--
Michael Press

On Nov 10, 4:44*pm, Michael Press wrote:
In article
,

" wrote:
On Nov 9, 11:11*am, Mike Rocket J Squirrel
wrote:
*From the "More Stuff on a Bicycle Is Better," Dept.

http://gizmodo.com/5079430/traffic-l...for-bikes-gets....

I wonder how this does on the sensors that are mounted to the light
and not embedded in the pavement? *On motorcycles, a common way to
trip the sensor if your bike doesn't have enough steel facing the
light is to angle the bike a bit and put your kickstand down. *I'm
guessing a bicycle kickstand still doesn't contain enough steel.

It need not be steel, only a conductive body that will have
eddy currents induced in it by the inductive loop in the pavement.

--
Michael Press

I take it that aluminum is far less conductive than steel then? I
know from experience of several of these sensors that my older mostly
steel Ninja would trip that the newer mostly aluminum R6 wouldn't.