a stupid question

[default]

I have one of those vehicle loop detectors installed on my property.
Same kind that operate traffic lights.

To test it (and the stuff I've added like lighting and alarms) I put a
2'X2' piece of sheet metal on the loop. That's unwieldy and a pain
because I have to store it some distance from the loop.

So I got a detector and wired up a 4" dia loop ~30 T for ~80 uhy, or
what the 12' loop with 3T should produce.

Works like a champ, but ferrite makes it go crazy (loop detects the
ferrite leaving the loop one time, and then detects it entering from
then on) - there's a microprocessor involved in the innards of the
commercial loop detector.

Then I tried a shorted turn and that seems to work on the 4" loop but
not even a 4' diameter shorted turn will trigger the 12' loop. Yet a
1" diameter shorted turn will trigger the 4" loop.

Small, very powerful magnets - nada. It won't see them.

So far it looks like a piece of chicken wire fencing ~2'X4' is the
best I've been able to do. Triggers the loop and is not so much
hassle to carry around so I can make a dummy "target" and leave it out
by the loop without it looking like roadside trash. (so the city
doesn't get pissed off)

Anyone with some ideas on how to trigger traffic loop detectors? (and
I ride a motorcycle too, so this ain't just an exercise in logic)

 

[Tim Wescott]

On Fri, 21 Oct 2016 13:35:36 -0400, default wrote:

I have one of those vehicle loop detectors installed on my property.
Same kind that operate traffic lights.

To test it (and the stuff I've added like lighting and alarms) I put a
2'X2' piece of sheet metal on the loop. That's unwieldy and a pain
because I have to store it some distance from the loop.

So I got a detector and wired up a 4" dia loop ~30 T for ~80 uhy, or
what the 12' loop with 3T should produce.

Works like a champ, but ferrite makes it go crazy (loop detects the
ferrite leaving the loop one time, and then detects it entering from
then on) - there's a microprocessor involved in the innards of the
commercial loop detector.

Then I tried a shorted turn and that seems to work on the 4" loop but
not even a 4' diameter shorted turn will trigger the 12' loop. Yet a 1"
diameter shorted turn will trigger the 4" loop.

Small, very powerful magnets - nada. It won't see them.

So far it looks like a piece of chicken wire fencing ~2'X4' is the best
I've been able to do. Triggers the loop and is not so much hassle to
carry around so I can make a dummy "target" and leave it out by the loop
without it looking like roadside trash. (so the city doesn't get pissed
off)

Anyone with some ideas on how to trigger traffic loop detectors? (and I
ride a motorcycle too, so this ain't just an exercise in logic)

I'm pretty sure that you just need the perimeter to be conductive. So a
2' diameter loop of wire should work just fine. In fact, you could break
the loop and have it "disappear", then connect it again and have it
"appear".

Back when my knees allowed me to commute by bicycle, I could reliably
trigger traffic lights by centering myself over the pick-up loop and
angling the bike down (by about 45 degrees) so that the main triangle was
laid over the loop. This worked quite well. It may be challenging to do
this with a Harley or a Gullwing, however.

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

I'm looking for work -- see my website!

 

[amdx]

On 10/21/2016 12:35 PM, default wrote:

I have one of those vehicle loop detectors installed on my property.
Same kind that operate traffic lights.

To test it (and the stuff I've added like lighting and alarms) I put a
2'X2' piece of sheet metal on the loop. That's unwieldy and a pain
because I have to store it some distance from the loop.

So I got a detector and wired up a 4" dia loop ~30 T for ~80 uhy, or
what the 12' loop with 3T should produce.

Works like a champ, but ferrite makes it go crazy (loop detects the
ferrite leaving the loop one time, and then detects it entering from
then on) - there's a microprocessor involved in the innards of the
commercial loop detector.

Then I tried a shorted turn and that seems to work on the 4" loop but
not even a 4' diameter shorted turn will trigger the 12' loop. Yet a
1" diameter shorted turn will trigger the 4" loop.

Small, very powerful magnets - nada. It won't see them.

So far it looks like a piece of chicken wire fencing ~2'X4' is the
best I've been able to do. Triggers the loop and is not so much
hassle to carry around so I can make a dummy "target" and leave it out
by the loop without it looking like roadside trash. (so the city
doesn't get pissed off)

Anyone with some ideas on how to trigger traffic loop detectors? (and
I ride a motorcycle too, so this ain't just an exercise in logic)

This product has an Amazon 4 star rating, but also some reviews say it
doesn't always work. One guy had 3 troublesome lights on his route, it
worked on two of them.
> https://www.amazon.com/Greenlight-Stuff-Trigger-Manufacturer-GREENLIGHT/dp/B00D9GZSF4

Mikek

 

[Jasen Betts]

On 2016-10-21, default <default@defaulter.net> wrote:

I have one of those vehicle loop detectors installed on my property.
Same kind that operate traffic lights.

To test it (and the stuff I've added like lighting and alarms) I put a
2'X2' piece of sheet metal on the loop. That's unwieldy and a pain
because I have to store it some distance from the loop.

use it for baking cookies when not testing the loop.

So I got a detector and wired up a 4" dia loop ~30 T for ~80 uhy, or
what the 12' loop with 3T should produce.

Works like a champ, but ferrite makes it go crazy (loop detects the
ferrite leaving the loop one time, and then detects it entering from
then on) - there's a microprocessor involved in the innards of the
commercial loop detector.

why is that a problem? is your car made of ferrite?

this does suggest that the sensor is looking for a decrease in
inductance.

does steel work correctly ?

So far it looks like a piece of chicken wire fencing ~2'X4' is the
best I've been able to do. Triggers the loop and is not so much
hassle to carry around so I can make a dummy "target" and leave it out
by the loop without it looking like roadside trash. (so the city
doesn't get pissed off)

how about a few metres of copper wire in a loop,

Anyone with some ideas on how to trigger traffic loop detectors? (and
I ride a motorcycle too, so this ain't just an exercise in logic)

when riding a push bike I stop with the front wheel over, and aligned
with the cut where the loop is, for me it works every time.

I've seen a traffic jam caused by a loop of steel packing strap lying
on one sensor, messing up the traffic light timing near the end of a
freeway.

--
This email has not been checked by half-arsed antivirus software

 

[default]

On 22 Oct 2016 08:52:56 GMT, Jasen Betts <jasen@xnet.co.nz> wrote:

On 2016-10-21, default <default@defaulter.net> wrote:
I have one of those vehicle loop detectors installed on my property.
Same kind that operate traffic lights.

To test it (and the stuff I've added like lighting and alarms) I put a
2'X2' piece of sheet metal on the loop. That's unwieldy and a pain
because I have to store it some distance from the loop.

use it for baking cookies when not testing the loop.

So I got a detector and wired up a 4" dia loop ~30 T for ~80 uhy, or
what the 12' loop with 3T should produce.

Works like a champ, but ferrite makes it go crazy (loop detects the
ferrite leaving the loop one time, and then detects it entering from
then on) - there's a microprocessor involved in the innards of the
commercial loop detector.

why is that a problem? is your car made of ferrite?

My thinking was that ferrite would work well because it should shift
the frequency more than other metals. (the object is to find
something that reliably triggers the loop, and doesn't take up a lot
of room)

this does suggest that the sensor is looking for a decrease in
inductance.

does steel work correctly ?

Sheet metal works well, but misses out in the small compact design
goal. Type of metal, either doesn't matter or matters very little.

So far it looks like a piece of chicken wire fencing ~2'X4' is the
best I've been able to do. Triggers the loop and is not so much
hassle to carry around so I can make a dummy "target" and leave it out
by the loop without it looking like roadside trash. (so the city
doesn't get pissed off)

how about a few metres of copper wire in a loop,

I wish I'd thought of the idea one responder had; an open loop then
shorting it to make it trigger the detector - then I could have buried
both the detector loop along with the test loop.

But that gives me another idea that aught to work - a small capacitor
or inductor that I can switch in parallel with the loop to shift the
frequency. Ferrite donut with a turn or two of wire is small compact
and can stay inside the detector housing with just a switch on the
outside. I'll give that a try as soon as it gets light enough
outside.

As a testing device a large loop still needs support and a frame of
some sort.

Anyone with some ideas on how to trigger traffic loop detectors? (and
I ride a motorcycle too, so this ain't just an exercise in logic)

when riding a push bike I stop with the front wheel over, and aligned
with the cut where the loop is, for me it works every time.

I've seen a traffic jam caused by a loop of steel packing strap lying
on one sensor, messing up the traffic light timing near the end of a
freeway.

Thanks to you and others I have a few more things to try. thanks guys

 

[default]

On Fri, 21 Oct 2016 15:44:28 -0500, amdx <nojunk@knology.net> wrote:

On 10/21/2016 12:35 PM, default wrote:
I have one of those vehicle loop detectors installed on my property.
Same kind that operate traffic lights.

To test it (and the stuff I've added like lighting and alarms) I put a
2'X2' piece of sheet metal on the loop. That's unwieldy and a pain
because I have to store it some distance from the loop.

So I got a detector and wired up a 4" dia loop ~30 T for ~80 uhy, or
what the 12' loop with 3T should produce.

Works like a champ, but ferrite makes it go crazy (loop detects the
ferrite leaving the loop one time, and then detects it entering from
then on) - there's a microprocessor involved in the innards of the
commercial loop detector.

Then I tried a shorted turn and that seems to work on the 4" loop but
not even a 4' diameter shorted turn will trigger the 12' loop. Yet a
1" diameter shorted turn will trigger the 4" loop.

Small, very powerful magnets - nada. It won't see them.

So far it looks like a piece of chicken wire fencing ~2'X4' is the
best I've been able to do. Triggers the loop and is not so much
hassle to carry around so I can make a dummy "target" and leave it out
by the loop without it looking like roadside trash. (so the city
doesn't get pissed off)

Anyone with some ideas on how to trigger traffic loop detectors? (and
I ride a motorcycle too, so this ain't just an exercise in logic)

This product has an Amazon 4 star rating, but also some reviews say it
doesn't always work. One guy had 3 troublesome lights on his route, it
worked on two of them.
https://www.amazon.com/Greenlight-Stuff-Trigger-Manufacturer-GREENLIGHT/dp/B00D9GZSF4

Mikek

It is just a magnet and I've already tried some pretty damn strong
magnets to no good effect. But then I haven't really tried them on
the motorcycle and the magnet + frame might matter more than the
magnet alone.

I do keep a 1" dia X 1/2" neodymium stuck on the oil drain plug to
slurp up any particles that are floating around in the oil.

 

[default]

On Fri, 21 Oct 2016 13:38:26 -0500, Tim Wescott
<seemywebsite@myfooter.really> wrote:

On Fri, 21 Oct 2016 13:35:36 -0400, default wrote:

I have one of those vehicle loop detectors installed on my property.
Same kind that operate traffic lights.

To test it (and the stuff I've added like lighting and alarms) I put a
2'X2' piece of sheet metal on the loop. That's unwieldy and a pain
because I have to store it some distance from the loop.

So I got a detector and wired up a 4" dia loop ~30 T for ~80 uhy, or
what the 12' loop with 3T should produce.

Works like a champ, but ferrite makes it go crazy (loop detects the
ferrite leaving the loop one time, and then detects it entering from
then on) - there's a microprocessor involved in the innards of the
commercial loop detector.

Then I tried a shorted turn and that seems to work on the 4" loop but
not even a 4' diameter shorted turn will trigger the 12' loop. Yet a 1"
diameter shorted turn will trigger the 4" loop.

Small, very powerful magnets - nada. It won't see them.

So far it looks like a piece of chicken wire fencing ~2'X4' is the best
I've been able to do. Triggers the loop and is not so much hassle to
carry around so I can make a dummy "target" and leave it out by the loop
without it looking like roadside trash. (so the city doesn't get pissed
off)

Anyone with some ideas on how to trigger traffic loop detectors? (and I
ride a motorcycle too, so this ain't just an exercise in logic)

I'm pretty sure that you just need the perimeter to be conductive. So a
2' diameter loop of wire should work just fine. In fact, you could break
the loop and have it "disappear", then connect it again and have it
"appear".

And a small toroid inductor that parallels the loop may achieve the
same thing. So thanks for that idea.

Back when my knees allowed me to commute by bicycle, I could reliably
trigger traffic lights by centering myself over the pick-up loop and
angling the bike down (by about 45 degrees) so that the main triangle was
laid over the loop. This worked quite well. It may be challenging to do
this with a Harley or a Gullwing, however.

I hear you. I'd ride my bicycle to keep my heart rate up at 140 for
an hour a day, until my knees started getting painful after several
years... Now I paddle a kayak 4 miles every day - so I guess my
wrists or fingers will be the limiting factor some day.

Exercise makes everything else work better when one starts to show
signs of age...

 

[Helmut Wabnig]

On Fri, 21 Oct 2016 13:35:36 -0400, default <default@defaulter.net>
wrote:

I have one of those vehicle loop detectors installed on my property.
Same kind that operate traffic lights.

To test it (and the stuff I've added like lighting and alarms) I put a
2'X2' piece of sheet metal on the loop. That's unwieldy and a pain
because I have to store it some distance from the loop.

So I got a detector and wired up a 4" dia loop ~30 T for ~80 uhy, or
what the 12' loop with 3T should produce.

Works like a champ, but ferrite makes it go crazy (loop detects the
ferrite leaving the loop one time, and then detects it entering from
then on) - there's a microprocessor involved in the innards of the
commercial loop detector.

Then I tried a shorted turn and that seems to work on the 4" loop but
not even a 4' diameter shorted turn will trigger the 12' loop. Yet a
1" diameter shorted turn will trigger the 4" loop.

Small, very powerful magnets - nada. It won't see them.

So far it looks like a piece of chicken wire fencing ~2'X4' is the
best I've been able to do. Triggers the loop and is not so much
hassle to carry around so I can make a dummy "target" and leave it out
by the loop without it looking like roadside trash. (so the city
doesn't get pissed off)

Anyone with some ideas on how to trigger traffic loop detectors? (and
I ride a motorcycle too, so this ain't just an exercise in logic)

park a car on it.

w.

 

[Jasen Betts]

On 2016-10-22, default <default@defaulter.net> wrote:

On 22 Oct 2016 08:52:56 GMT, Jasen Betts <jasen@xnet.co.nz> wrote:

On 2016-10-21, default <default@defaulter.net> wrote:
I have one of those vehicle loop detectors installed on my property.
Same kind that operate traffic lights.

To test it (and the stuff I've added like lighting and alarms) I put a
2'X2' piece of sheet metal on the loop. That's unwieldy and a pain
because I have to store it some distance from the loop.

use it for baking cookies when not testing the loop.

So I got a detector and wired up a 4" dia loop ~30 T for ~80 uhy, or
what the 12' loop with 3T should produce.

Works like a champ, but ferrite makes it go crazy (loop detects the
ferrite leaving the loop one time, and then detects it entering from
then on) - there's a microprocessor involved in the innards of the
commercial loop detector.

why is that a problem? is your car made of ferrite?

My thinking was that ferrite would work well because it should shift
the frequency more than other metals. (the object is to find
something that reliably triggers the loop, and doesn't take up a lot
of room)

this does suggest that the sensor is looking for a decrease in
inductance.

does steel work correctly ?

Sheet metal works well, but misses out in the small compact design
goal. Type of metal, either doesn't matter or matters very little.


So far it looks like a piece of chicken wire fencing ~2'X4' is the
best I've been able to do. Triggers the loop and is not so much
hassle to carry around so I can make a dummy "target" and leave it out
by the loop without it looking like roadside trash. (so the city
doesn't get pissed off)

how about a few metres of copper wire in a loop,

I wish I'd thought of the idea one responder had; an open loop then
shorting it to make it trigger the detector - then I could have buried
both the detector loop along with the test loop.

as you have access to the wiring you could short terminals that
connect to the buried loop: the sensor seems to respond to reduced
impedance.

But that gives me another idea that aught to work - a small capacitor
or inductor that I can switch in parallel with the loop to shift the
frequency.

it may not be a free running oscillator, it may be a fixed frequency
transmitter and the load current monitored to detect metal

Ferrite donut with a turn or two of wire is small compact
and can stay inside the detector housing with just a switch on the
outside. I'll give that a try as soon as it gets light enough
outside.

you might just need the switch

--
This email has not been checked by half-arsed antivirus software

 

[default]

On Fri, 21 Oct 2016 13:35:36 -0400, default <default@defaulter.net>
wrote:

Ok empirical results: A dead short in the loop at the controller
will briefly twitch the output relay (so it triggers the timed lights
I've added) but then the controller tells me there's a bad loop
(inductance too low so there must be a short).

A small inductor I had laying around (unknown L) will fool it into
triggering just like a vehicle was present.

 

[Tim Wescott]

On Sat, 22 Oct 2016 06:17:23 -0400, default wrote:

On Fri, 21 Oct 2016 15:44:28 -0500, amdx <nojunk@knology.net> wrote:

On 10/21/2016 12:35 PM, default wrote:
I have one of those vehicle loop detectors installed on my property.
Same kind that operate traffic lights.

To test it (and the stuff I've added like lighting and alarms) I put a
2'X2' piece of sheet metal on the loop. That's unwieldy and a pain
because I have to store it some distance from the loop.

So I got a detector and wired up a 4" dia loop ~30 T for ~80 uhy, or
what the 12' loop with 3T should produce.

Works like a champ, but ferrite makes it go crazy (loop detects the
ferrite leaving the loop one time, and then detects it entering from
then on) - there's a microprocessor involved in the innards of the
commercial loop detector.

Then I tried a shorted turn and that seems to work on the 4" loop but
not even a 4' diameter shorted turn will trigger the 12' loop. Yet a
1" diameter shorted turn will trigger the 4" loop.

Small, very powerful magnets - nada. It won't see them.

So far it looks like a piece of chicken wire fencing ~2'X4' is the
best I've been able to do. Triggers the loop and is not so much
hassle to carry around so I can make a dummy "target" and leave it out
by the loop without it looking like roadside trash. (so the city
doesn't get pissed off)

Anyone with some ideas on how to trigger traffic loop detectors? (and
I ride a motorcycle too, so this ain't just an exercise in logic)

This product has an Amazon 4 star rating, but also some reviews say it
doesn't always work. One guy had 3 troublesome lights on his route, it
worked on two of them.
https://www.amazon.com/Greenlight-Stuff-Trigger-Manufacturer-
GREENLIGHT/dp/B00D9GZSF4

Mikek
It is just a magnet and I've already tried some pretty damn strong
magnets to no good effect. But then I haven't really tried them on the
motorcycle and the magnet + frame might matter more than the magnet
alone.

I do keep a 1" dia X 1/2" neodymium stuck on the oil drain plug to slurp
up any particles that are floating around in the oil.

AFAIK, a magnet isn't going to have any more effect on an inductive
pickup than an identical chunk of the same alloy that's not magnetized.
Simply put, the inductive coil is working at AC, and the magnet only
affects DC.

A magnet strong enough to affect the electrical behavior of your (steel)
frame would be enormous.

My uncle worked on one of the earliest inductive-pickup systems; his
"test car" was just a one-foot square sheet of aluminum (but, his pickup
coil was only about 18" in diameter, presumably with lots more turns).

--
www.wescottdesign.com

 

[John Larkin]

On Fri, 21 Oct 2016 13:35:36 -0400, default <default@defaulter.net>
wrote:

I have one of those vehicle loop detectors installed on my property.
Same kind that operate traffic lights.

To test it (and the stuff I've added like lighting and alarms) I put a
2'X2' piece of sheet metal on the loop. That's unwieldy and a pain
because I have to store it some distance from the loop.

So I got a detector and wired up a 4" dia loop ~30 T for ~80 uhy, or
what the 12' loop with 3T should produce.

Works like a champ, but ferrite makes it go crazy (loop detects the
ferrite leaving the loop one time, and then detects it entering from
then on) - there's a microprocessor involved in the innards of the
commercial loop detector.

Then I tried a shorted turn and that seems to work on the 4" loop but
not even a 4' diameter shorted turn will trigger the 12' loop. Yet a
1" diameter shorted turn will trigger the 4" loop.

Small, very powerful magnets - nada. It won't see them.

So far it looks like a piece of chicken wire fencing ~2'X4' is the
best I've been able to do. Triggers the loop and is not so much
hassle to carry around so I can make a dummy "target" and leave it out
by the loop without it looking like roadside trash. (so the city
doesn't get pissed off)

Anyone with some ideas on how to trigger traffic loop detectors? (and
I ride a motorcycle too, so this ain't just an exercise in logic)

There is probably some AC signal that you could pump into a small coil
that would fool the loop sensor.


--

John Larkin Highland Technology, Inc

lunatic fringe electronics

 

[Ron M.]

On Friday, October 21, 2016 at 12:55:06 PM UTC-5, default wrote:

I have one of those vehicle loop detectors installed on my property.
Same kind that operate traffic lights.

To test it (and the stuff I've added like lighting and alarms) I put a
2'X2' piece of sheet metal on the loop. That's unwieldy and a pain
because I have to store it some distance from the loop.

So I got a detector and wired up a 4" dia loop ~30 T for ~80 uhy, or
what the 12' loop with 3T should produce.

Works like a champ, but ferrite makes it go crazy (loop detects the
ferrite leaving the loop one time, and then detects it entering from
then on) - there's a microprocessor involved in the innards of the
commercial loop detector.

Then I tried a shorted turn and that seems to work on the 4" loop but
not even a 4' diameter shorted turn will trigger the 12' loop. Yet a
1" diameter shorted turn will trigger the 4" loop.

Small, very powerful magnets - nada. It won't see them.

So far it looks like a piece of chicken wire fencing ~2'X4' is the
best I've been able to do. Triggers the loop and is not so much
hassle to carry around so I can make a dummy "target" and leave it out
by the loop without it looking like roadside trash. (so the city
doesn't get pissed off)

Anyone with some ideas on how to trigger traffic loop detectors? (and
I ride a motorcycle too, so this ain't just an exercise in logic)

Back in the day working with Mot used to work on the drive thru stuff at Roy Rogers. I just placed my little fold up hand truck on the loop. Worked every time.

 

[default]

On Sat, 22 Oct 2016 20:28:17 -0700 (PDT), "Ron M."
<strmbrgr2@hotmail.com> wrote:

On Friday, October 21, 2016 at 12:55:06 PM UTC-5, default wrote:
I have one of those vehicle loop detectors installed on my property.
Same kind that operate traffic lights.

To test it (and the stuff I've added like lighting and alarms) I put a
2'X2' piece of sheet metal on the loop. That's unwieldy and a pain
because I have to store it some distance from the loop.

So I got a detector and wired up a 4" dia loop ~30 T for ~80 uhy, or
what the 12' loop with 3T should produce.

Works like a champ, but ferrite makes it go crazy (loop detects the
ferrite leaving the loop one time, and then detects it entering from
then on) - there's a microprocessor involved in the innards of the
commercial loop detector.

Then I tried a shorted turn and that seems to work on the 4" loop but
not even a 4' diameter shorted turn will trigger the 12' loop. Yet a
1" diameter shorted turn will trigger the 4" loop.

Small, very powerful magnets - nada. It won't see them.

So far it looks like a piece of chicken wire fencing ~2'X4' is the
best I've been able to do. Triggers the loop and is not so much
hassle to carry around so I can make a dummy "target" and leave it out
by the loop without it looking like roadside trash. (so the city
doesn't get pissed off)

Anyone with some ideas on how to trigger traffic loop detectors? (and
I ride a motorcycle too, so this ain't just an exercise in logic)

Back in the day working with Mot used to work on the drive thru stuff at Roy Rogers. I just placed my little fold up hand truck on the loop. Worked every time.

Loop diameter and target diameter ratio probably counts for more than
anything else. I tried a big heavy pipe wrench, crowbar, etc on the
small loop without it seeing it, but a tin can lid was triggering it
anywhere near the loop.

 

[default]

On Sat, 22 Oct 2016 14:10:42 -0500, Tim Wescott
<tim@seemywebsite.really> wrote:

On Sat, 22 Oct 2016 06:17:23 -0400, default wrote:

On Fri, 21 Oct 2016 15:44:28 -0500, amdx <nojunk@knology.net> wrote:

On 10/21/2016 12:35 PM, default wrote:
I have one of those vehicle loop detectors installed on my property.
Same kind that operate traffic lights.

To test it (and the stuff I've added like lighting and alarms) I put a
2'X2' piece of sheet metal on the loop. That's unwieldy and a pain
because I have to store it some distance from the loop.

So I got a detector and wired up a 4" dia loop ~30 T for ~80 uhy, or
what the 12' loop with 3T should produce.

Works like a champ, but ferrite makes it go crazy (loop detects the
ferrite leaving the loop one time, and then detects it entering from
then on) - there's a microprocessor involved in the innards of the
commercial loop detector.

Then I tried a shorted turn and that seems to work on the 4" loop but
not even a 4' diameter shorted turn will trigger the 12' loop. Yet a
1" diameter shorted turn will trigger the 4" loop.

Small, very powerful magnets - nada. It won't see them.

So far it looks like a piece of chicken wire fencing ~2'X4' is the
best I've been able to do. Triggers the loop and is not so much
hassle to carry around so I can make a dummy "target" and leave it out
by the loop without it looking like roadside trash. (so the city
doesn't get pissed off)

Anyone with some ideas on how to trigger traffic loop detectors? (and
I ride a motorcycle too, so this ain't just an exercise in logic)

This product has an Amazon 4 star rating, but also some reviews say it
doesn't always work. One guy had 3 troublesome lights on his route, it
worked on two of them.
https://www.amazon.com/Greenlight-Stuff-Trigger-Manufacturer-
GREENLIGHT/dp/B00D9GZSF4

Mikek
It is just a magnet and I've already tried some pretty damn strong
magnets to no good effect. But then I haven't really tried them on the
motorcycle and the magnet + frame might matter more than the magnet
alone.

I do keep a 1" dia X 1/2" neodymium stuck on the oil drain plug to slurp
up any particles that are floating around in the oil.

AFAIK, a magnet isn't going to have any more effect on an inductive
pickup than an identical chunk of the same alloy that's not magnetized.
Simply put, the inductive coil is working at AC, and the magnet only
affects DC.

A magnet strong enough to affect the electrical behavior of your (steel)
frame would be enormous.

My uncle worked on one of the earliest inductive-pickup systems; his
"test car" was just a one-foot square sheet of aluminum (but, his pickup
coil was only about 18" in diameter, presumably with lots more turns).

I wouldn't expect a magnet to have any effect on an inductive loop
sensor so I'm leery of the advertising claims of the one for sale on
Amazon. But there's inductive loop sensors and magnetometer sensors.
The magnetometer only senses moving metal/magnets so I wouldn't think
they'd find much application in traffic lights.

 

[default]

On Sat, 22 Oct 2016 15:56:09 -0700, John Larkin
<jjlarkin@highlandtechnology.com> wrote:

On Fri, 21 Oct 2016 13:35:36 -0400, default <default@defaulter.net
wrote:

I have one of those vehicle loop detectors installed on my property.
Same kind that operate traffic lights.

To test it (and the stuff I've added like lighting and alarms) I put a
2'X2' piece of sheet metal on the loop. That's unwieldy and a pain
because I have to store it some distance from the loop.

So I got a detector and wired up a 4" dia loop ~30 T for ~80 uhy, or
what the 12' loop with 3T should produce.

Works like a champ, but ferrite makes it go crazy (loop detects the
ferrite leaving the loop one time, and then detects it entering from
then on) - there's a microprocessor involved in the innards of the
commercial loop detector.

Then I tried a shorted turn and that seems to work on the 4" loop but
not even a 4' diameter shorted turn will trigger the 12' loop. Yet a
1" diameter shorted turn will trigger the 4" loop.

Small, very powerful magnets - nada. It won't see them.

So far it looks like a piece of chicken wire fencing ~2'X4' is the
best I've been able to do. Triggers the loop and is not so much
hassle to carry around so I can make a dummy "target" and leave it out
by the loop without it looking like roadside trash. (so the city
doesn't get pissed off)

Anyone with some ideas on how to trigger traffic loop detectors? (and
I ride a motorcycle too, so this ain't just an exercise in logic)

There is probably some AC signal that you could pump into a small coil
that would fool the loop sensor.

No doubt. The loops themselves have to reject 60 cycle hum so there's
probably a notch or high pass filter. The loops change frequency
slowly over time with temperature and rainfall and the microprocessor
has to compensate for that and only see the relatively faster changes
a vehicle makes. They do tune themselves too - switch capacitors in
and out to set the frequency and there's a switch selection for high
medium and low frequency to minimize interference with nearby loops.

But a pick-up loop on the bike sensing the frequency could output a
burst of some powerful but slightly different frequency... I'm not
looking for a new career. If my MC can't make it trigger what hope do
bicycles have?

And the DOT suggestion that one ride close to the edge of the loop?
The center of the loop works better IMO. Dealing with the bureaucracy
at DOT is another pain. It takes several phone calls or emails to get
them to reset and recheck the sensitivity and things will be fine for
a time, until someone complains because people driving cars will "cut
the chord" if there are no vehicles present in the perpendicular lane
and also trigger the light.

I'm sure the technology will improve enough to fix the problem...
eventually...when they find the money.... make the effort...

 

[amdx]

On 10/22/2016 9:40 AM, default wrote:

On Fri, 21 Oct 2016 13:35:36 -0400, default <default@defaulter.net
wrote:

Ok empirical results: A dead short in the loop at the controller
will briefly twitch the output relay (so it triggers the timed lights
I've added) but then the controller tells me there's a bad loop
(inductance too low so there must be a short).

A small inductor I had laying around (unknown L) will fool it into
triggering just like a vehicle was present.

I posted this 12 hrs ago and don't see it, may end up with a double.

What is the frequency of operation?

How about a ferrite rod?

A ferrite rod with shorted turns?

How about a tuned ferrite loop?

I'm tempted to go play with ferrites at a traffic light!

Mikek

Large plastic coated ferrite rods.
> http://www.stormwise.com/page26.htm

But you can probably do it cheaper stacking potcores.
I have some big a$$ potcores, 3C81 material
>
http://i395.photobucket.com/albums/pp37/Qmavam/74f45770-4315-4ffc-9ccb-fa5486d51951_zps359f8946.png
$12 ea plus shipping.

 

[default]

On Sun, 23 Oct 2016 20:25:54 -0500, amdx <nojunk@knology.net> wrote:

On 10/22/2016 9:40 AM, default wrote:
On Fri, 21 Oct 2016 13:35:36 -0400, default <default@defaulter.net
wrote:

Ok empirical results: A dead short in the loop at the controller
will briefly twitch the output relay (so it triggers the timed lights
I've added) but then the controller tells me there's a bad loop
(inductance too low so there must be a short).

A small inductor I had laying around (unknown L) will fool it into
triggering just like a vehicle was present.


I posted this 12 hrs ago and don't see it, may end up with a double.

What is the frequency of operation?

How about a ferrite rod?

A ferrite rod with shorted turns?

How about a tuned ferrite loop?

I'm tempted to go play with ferrites at a traffic light!

Mikek

Large plastic coated ferrite rods.
http://www.stormwise.com/page26.htm

But you can probably do it cheaper stacking potcores.
I have some big a$$ potcores, 3C81 material

http://i395.photobucket.com/albums/pp37/Qmavam/74f45770-4315-4ffc-9ccb-fa5486d51951_zps359f8946.png
$12 ea plus shipping.

From my original post. Ferrite was the first thing I tried, screws up
the detector so that it causes it to trigger ON when the ferrite is
removed from the small test coil and has no effect on the 12'
diameter loop. Have to press the reset or cycle the power to get it
working so it is on when metal is detected.

I used a stack of 1/2" ID 1-3/8" OD stacked on a 1/2" CPVC water pipe
9" long.

I didn't try a shorted turn on ferrite though...

The loop pretty much just sits there so I don't expect to use a piece
of sheet metal too often - I really wanted something to test the stuff
I've added which turn on when the detector turns on.