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sensors at the traffic lights(13 posts)

sensors at the traffic lightssafoora
Aug 6, 2002 4:12 PM
What to do if you want to turn left and the sensor is
not detecting you, so the lights stay red? Do you walk the bike around the intersection?
A couple of tricksKerry
Aug 6, 2002 4:42 PM
I've found that the sensors are more sensitive at the edges to "seeing" the bike. If you place yourself right at the edge of the sensor, it is more likely to pick up. Unfortunately, you have to wait a while to find out. Another trick is to lay the bike on its side, or at least lean it way over. Again you are presenting a different "picture" to the sensor - I've had this work as well. If neither of these works, I'd wait for traffic to clear and then treat the light as though it were a stop sign.
A couple of tricksszybki
Aug 6, 2002 5:09 PM
you must have a steel bike...
Aluminium works fine.Pygme
Aug 6, 2002 6:45 PM
I have a C'dale, Cinelli, and a Trek 8000 all aluminum. The lay-the-bike-on-its-side-trick works great with all of them.
Don't understandNessism
Aug 6, 2002 7:08 PM
I thought the wire loop in the pavement is looking for something magnetic to brake the electrical field (read: iron). How is it that Al works?

Ed
Don't understandLen J
Aug 7, 2002 3:59 AM
Carbon works also. I think it's the metal in the component group that trips the sensor.

Len
jeeez. my motorycle doesnt even have enough metal to trip it.Steve_0
Aug 7, 2002 4:20 AM
I dont eitherPygme
Aug 7, 2002 5:07 AM
i dont understand either, but it works. Try it.
some lights...phlegm
Aug 7, 2002 7:22 AM
are triggered by optic sensors.
Nope - They work like this...W6UV
Aug 7, 2002 11:58 AM
I thought the wire loop in the pavement is looking for something magnetic to brake the electrical field (read: iron). How is it that Al works?

No. The burried loops form part of a tuned RF circuit. Any metallic object coming into proximity with the circuit detunes it, which the control circuitry detects as a change in frequency. The principle is the same as that used in mine detectors and metal detectors used at airports.

The key to getting these things to "see" your bike is to align your bike parallel over one of the edges of the sensor. An edge is more sensitive than the center of the loop. Sometimes rocking the bike back and forth helps.
re: sensors at the traffic lightsfirstrax
Aug 6, 2002 5:49 PM
Build an IR strobe that flashes at 60hz. Instantly turns your lane green and all others red.
Green Lightchar
Aug 6, 2002 6:40 PM
You could try this out, it was mentioned earlier on rbr.
http://www.greenlighttrigger.com/

I can usually get the lights to trip by riding very slowly over the loop that is parallel to the road direction. If there is heavy traffic, the duration of the traffic lights seems to change and sometime this doesn't work. I treat it as a stop sign and move on without being too blatant.

Charlie
Green Lightcurlybike
Aug 7, 2002 6:44 AM
Based on stuff I found at the link, can't we go to Radio Shack and get one of those cheap Perm. Magnets they sell and glue it to the toe of our shoe on the putdown foot and just wave it over the inductive wire as we go over? Putting it on the toe will get as close as possible to the wire so a pretty small magnet may work. Just a thought.