Red Light Changer

[liveforphysics]

Yeah, who needs tow-chains, anyway. Just pull up close to the vehicle, latch on, and drive away with the both of you. :lol:


Realistically, if you have old dead harddrives laying around, you could just pull the arm magnets out of it, stick them on your frame, and it'd probably work for many lights. I'm not sure if more separate ones in different places on the frame works better than sticking them all into one physically large block, as I haven't tried that experiment yet.

Yes, inherently, we know that just a a single HD magnet mounted low does the trick well (as thousands of motorcyclists have learned).

However, it seems likely it's the MuMetal that always comes on the back of a HD magnet to shield it that causes the desired effect over the magnet itself.

 

[Kingfish]

Yeah, who needs tow-chains, anyway. Just pull up close to the vehicle, latch on, and drive away with the both of you. :lol:


Realistically, if you have old dead harddrives laying around, you could just pull the arm magnets out of it, stick them on your frame, and it'd probably work for many lights. I'm not sure if more separate ones in different places on the frame works better than sticking them all into one physically large block, as I haven't tried that experiment yet.

Yes, inherently, we know that just a a single HD magnet mounted low does the trick well (as thousands of motorcyclists have learned).

However, it seems likely it's the MuMetal that always comes on the back of a HD magnet to shield it that causes the desired effect over the magnet itself.

Hmmm. Which side? Magnet to frame, MuMetal down twoards Earth? :?
Divining, KF

 

[liveforphysics]

I think all orientations should work approximately equally (due to the large difference in coil size vs the magnet/metal size).

 

[regmeister]

deleted

 

[amberwolf]

However, it seems likely it's the MuMetal that always comes on the back of a HD magnet to shield it that causes the desired effect over the magnet itself.

I didn't realize MuMetal was used on them, though that makes sense. In all the ones I have, the magnets themselves appear to be simple arcs of neo magnet, with nickel plating. If there is MuMetal, it must be that entire metal bracket that the magnet is bonded to. I thought those were steel (never tested the theory, though, just assumed).

So if those are MuMetal, then I have a pretty large amount of it in those brackets in a box somewhere, that I'd managed to separate from the magnets.

If that is the case, then it also explains why the magnets that I coudln't get the brackets off of have seemed to often work better for triggering lights than the ones I did. I originally figured it was just the larger metal mass concentrating field lines better, but that doesn't really make sense now with what I've read in this thread. Maybe they really do work better, because of the MuMetal?

 

[fechter]

I have a traffic loop amplifier and a small pre-formed loop. The amplifier is not triggered by my refrigerator magnets, and several are strong neo's.

A full 2.5" HD triggers it. I don't have the MU backed magnet to test with. Maybe later.

The loop I'm using is only a foot or so in diameter, and it's still a bit hard to test it inside my apartment with all the metal. Ideally it should at least be a 6x6 outside, and wrapped 3 times.

Plenty of loop info at this link.

That sounds like a better way to test theories than standing in the middle of a traffic lane. :wink:

One thing to test would be to pass the strong neo magnet over the coil quickly, since this would generate a voltage in the coil that's a function of the speed. I suspect the amplifier is designed to reject this kind of signal, but who knows.

Another test would be to try a piece of thin steel sheet metal, like a tin can or pie tin. It has to be something that sticks to a magnet.
The idea is to figure out whether a rather large (shoe sized) but thin sheet will trigger it and which orientation is the best.

The Mu metal on the backing of a hard drive magnet is not the same stuff that they use for shielding. The kind used for magnet backing is "high saturation" Mu metal, which the guy at company told me is just a low carbon steel. The "high permeability" kind used for shielding saturates at a much lower flux, but has much, much higher permeability, which I think is the property we want to trigger the sensor coil.

 

[regmeister]

deleted

 

[fechter]

I'll try some of this stuff:


This seems to be about the thickness of a coffee can.

 

[mdd0127]

Fechter hit on something. When I put the magnet on my dirtbike, at first, it didn't work. I thought about it and thought that maybe it was because the bike had so much clearance so I tried hitting the front brake and shifting my weight at just the right time to squash the bike down over the sensor loop and it was like a switch. The lights would reliably change after a few seconds. Maybe it was the magnet moving at speed above the loop and not just the distance? I haven't ridden in so long I'd forgotten about that. A tiny EMP device would probably trip one too.......and stop tailgaters in their tracks......

 

[MitchJi]

Hi,

I don't know if either of these work or not (if it works the remote is excellent 8) ).
With Magnets on your bike:
[youtube]8GAacxGiV4A[/youtube]

With a Universal remote:
[youtube]iZL_QlxBqQs[/youtube]

 

[Blueshift]

I have been trying to think of an idea for my bike to be able to pick up on a stop light. It is weird going down the vehicle lane only to have to push the light on the walking lane.

Will magnets work?
Anybody got any pics of things they have added to pick up on a stop light sensor?

 

[mwkeefer]

Traffic lights are triggered by Photo Strobe pulse of a frequency which I will not specify here as to implement this on a bike or car would be illegal in all 50 states. Give better timing a try, I find at the right speeds I can make every light without even slowing down

-Mike

 

[Rassy]

If you are talking about tripping the embedded sensor (legally) here is an old thread that discusses it.

http://www.endless-sphere.com/forums/viewtopic.php?f=3&t=24399&hilit=traffic+signal+magnet

 

[amberwolf]

There's a discussion a couple years back that includes details by someone that has worked on those systems, as to what will and won't work, and how those systems actually function.
(edit: while I was typing, Rassy posted the link to that thread above me)


But it all depends on how the sensor at any particular intersection is set.

For instance, Glendale here in AZ has a lot of intersections with bicycle lane sensors--yet many of them don't trigger on any of my pedal bikes, or ebikes, even when I have a trailer load of ferrous metal stuff on there and make sure to park it right over the sensor, or move back and forth, etc.

Yet I can move over a lane and activate the *car* sensor easily!

Sometimes one lane will activate easily, and another wont' even activate for a car!

So it is hit and miss as to what will and won't work.

I have tried a huge handful of harddisk magnets, some old ceramic speaker magnets, etc., and on some sensors they appear to make a difference, and on others they do not.

It makes *more* of a difference if I ride over the actual cut line where the sensor loop is embedded, either in the center or to either side, but if a sensor won't activate, it usually wont' do it no matter what.


On my 12.5-mile (each way) commute the last couple weeks to a different store than usual, there are two intersections I would always have to just wait till no traffic was coming, and go thru despite the red light, because the traffic control is not functioning correctly and will not detect my trike or the trailer (both of which are steel). IIRC it's 63rd Ave for both, at Bell and at Greenway, northbound. There is no car traffic on 63rd Ave at that time of the morning (almost 530am), at those intersections, excepting the occasional right-turner that doesnt' even stop for the intersection--they sort of slow down and turn anyway (because there is also almost no traffic east/west either).


AFAIK in most places it is legal to go thru the light even if red, as long as there is no cross traffic, if you stop first and if the light does not change. Some places require a certain number of light cycles and some requrie waiting a certain period of time, but really, if you cross that intersection all the time and know that your vehicle cannot trigger the sensors, there's not much point in waiting except for traffic to clear, unless you know the police are waiting there for you and will ticket you for it. Or you just prefer to stick to the letter of the law.

Give better timing a try, I find at the right speeds I can make every light without even slowing down

That doesnt' work for lights that ONLY change when a vehicle trips the sensor loop embedded in the roadway. Many intersections are setup that way here in Phoenix, especially non-major roads. Some (like Cheryl at Metro Parkway) will change as you ride over the sensor, so you only have to slow down a little to not go into the intersection while it's still red, but that's only for the ones that actually respond to smaller-than-car-sized vehicles. Too many of them don't even see motorcycles, and some of them don't respond to some of the small light cars either.

 

[mwkeefer]

Actually a paint ball gun firing rubber balls would work if your aim is decent, you could hit the button without getting up... get good at it and your 1/2 way to a Super Hero or Hollywood stuntman.

And yea that feeling at the drive through where you can't trip the damn sensors cause you don't weigh enough... I still can't get over that or figure a way around - maybe a really heavy chopper style build I have planned for not too far off.

-Mike

 

[amberwolf]

Unfortunately here there are often enough no walk buttons. They simply come on automatically when the green light happens (or at some ohter point in the timing sequence), so pedestrians also get no chance to cross at intersections where there is no traffic. Ain't that stupid?

 

[drewjet]

You can also call your local traffic department and give them the info on which lights wont activate and they will go out and make them more sensative.

 

[lbz5mc12]

Then of course there are the lights that are on a timer and change not based on the traffic but on a time loop. There are 4 intersections right near where I live that are on timers.

 

[dogman dan]

Sounds like in AW's town, they put the car sensor in the bike lane, and the bike sensor in the car lane.

Only thing that reliably worked for me, was follow a car when possible. If one is conveniently coming, pause and let him get on the damn sensor.

I've done the left turn followed by a u turn a few times, if that is actually legal.

Run it if the road is that empty, and you can see enough to know there is no cop lurking in the dark.

Lights need to be programmed to briefly let every lane go each cycle. I really hate the few lights in town that will actually never let you go unless the sensor is tripped. Even in a car, it's like they let you go only after you sit there 90 seconds on the sensor. If traffic at that light is that light on the small cross street, it should just be a damn stop sign.

 

[amberwolf]

You can also call your local traffic department and give them the info on which lights wont activate and they will go out and make them more sensative.

I've been trying that for years (since long before I got into ebiking), and they don't seem to actually do anything about it. Sometimes things get worse suddenly a few months after the call, but never better. When traffic lights are burned out, they do take care of those, but not the sensors.

Lots of regular cyclists never even ride onto the bike lane sensors, bu tinstead ride up onto the sidewalk, press the walk button, wait for the walk signal, and ride across the crosswalk, because that's faster, when there is a lot of cross-traffic you can't ride thru but no thru-traffic to trigger a green. Unfortunately so many intersections don't have walk buttons these days that this can't be done at, sometimes you just have to wait fora break in traffic and go anyway.

Then of course there are the lights that are on a timer and change not based on the traffic but on a time loop. There are 4 intersections right near where I live that are on timers.

I'd be much happier with those--I could learn the timing and just adjust my speed to make it thru just as it turns green. That's what I used to do.

Sounds like in AW's town, they put the car sensor in the bike lane, and the bike sensor in the car lane.

It sure feels like it sometimes. :lol:

Only thing that reliably worked for me, was follow a car when possible. If one is conveniently coming, pause and let him get on the damn sensor.

That's another thing I do, but fi the sensors don't work it doesnt' help. Then both of us just have to wait for traffic to clear and cross anyway.

I've done the left turn followed by a u turn a few times, if that is actually legal.

Right turn then U would be better, because then you don't have to run the light to do it. Making a left turn you might as well just go straight thru, becuase you would have to make *another* left turn after the U to get back on the road direction you were on to start with.
At least, that's how it works here. There are a few intersections marked "no right on red" and actually have a right-turn arrow, that unless it is green you're not allowed to go (28th Ave at north end of Metrocenter, right turn to eastbound Peoria, is one such), but there's not many of them and most of them also have a median on the cross-street that would prevent the U turn as well, until you're at least a 1/4 mile down the road.

Lights need to be programmed to briefly let every lane go each cycle. I really hate the few lights in town that will actually never let you go unless the sensor is tripped. Even in a car, it's like they let you go only after you sit there 90 seconds on the sensor. If traffic at that light is that light on the small cross street, it should just be a damn stop sign.

Here, most of the lights that never trip properly do have a cycle...but without the sensor trip they dont' actually go thru with the green part of it. YOu can see the cross-traffic-light countdown for don't-walk, or the flashing hand, but then it just turns walk again and never changes from a green light. There used to be one intersection that would go all the way to a yellow light and then turn green again, but they fixed that part. It still wont' trigger correctly, though, for the thru-traffic part on the smaller road I need to use to cross it.

Most of the ones I have a problem with are in Glendale, but quite a few in Phoenix have such problems. Some in Peoria but they are usually only after road work in the area and they tend to fix them reasonably quickly.

 

[amberwolf]

And yea that feeling at the drive through where you can't trip the damn sensors cause you don't weigh enough... I still can't get over that or figure a way around - maybe a really heavy chopper style build I have planned for not too far off.

I don't know that the drive thrus use weight sensors, at least not here--they seem to use the same kind of embedded loop sensors, or they use an IR beam sensor on a few really old ones.

I have no trouble even on a pedal bike tripping most of them--the catch is that almost none of hte places will serve anyone on a bike (evne a motorcycle!) in the drive thru--when you get up to the window they refuse to take your money or give you your food, and tell you you have to come inside. (if they even post any policy about who they will serve at the drive up, it's only at the window itself, whcih can't be seen from the ordering area, and it almost always only ever says "no walk ups", which does not exclude anyone but pedestrians).

((I usually just tell them "That's strange, you don't have it posted. It's too bad that you just wasted both our time, and your food. I won't be ever be returning to your business, and I'll let everyone I know how you treat people that arent' wasteful enough to ride in cars", and then I leave. And I don't go back to them, either, even if I'm with someone else. So there are a lot of fast food places around town that I won't do business with, even if someone else is buying--I'll tell whoever I'm with and we'll go find somewhere else. (not that I eat out more than a few times a year on my own, but it's not uncommon for me to be helping someone else and have them want to or offer to stop for food on the way there or back). ))

 

[zombiess]

Traffic lights are triggered by Photo Strobe pulse of a frequency which I will not specify here as to implement this on a bike or car would be illegal in all 50 states. Give better timing a try, I find at the right speeds I can make every light without even slowing down

-Mike

I may or may not have tested an IR LED array for range at a certain frequency on an unencoded opticom system several years ago. Was begged and offered some nice money from a few friends after i showed them, but I wouldn't sell due to the havoc it would cause. I also reminded them all MIRT intersections have cameras.

Its sitting in a box next to some kind of jamming device that was used on occasion to teach some etiquette in public....

 

[MadRhino]

I consider red lights as stop signs, and ride them as soon as there is no one to bother.
Having a device that would switch them to green, would be just as illegal as riding the red anyway.

 

[brainfarth]

I've read many articles and comments on whether neodymium magnets will change traffic lights. Most people say it cant be done. And I've even placed a magnet in my shoe and danced around the intersection inductance coil with negative results.
So I decided to take another swing at it. This time, I taped a 1/2" x 1/2" magnet with the north down and one with south down, under my bike frame. I rode up to an intersection that I knew was a triggered light and went through the middle of the coils(pretty obvious where they are located because of the tar circles in the road). The light did not change.
I went for a second try the following day, but this time I aimed for around 1/3rd the distance from the side of the circle and the light immediately reacted. I was pretty excited with the results. But to make sure it was not a fluke, I rolled up to the light for a 3rd time in the same place and it changed for me again.
I dont know if the north/south configuration has anything to do with it, but I figured I would cover my bases. I will try for both north and south in the future. But for now, I'm pretty content with the setup as it is.
It's so nice not having to wait for a car to change the light or going to the cross walk and pressing the button.

 

[Alan B]

The magnetic field falls off quickly with distance. If you can position your magnets close to the roadbed they would have a much stronger coupling to the coils (not sure whether that would solve the problem or not however).