View Single Post
Old 04-27-2010, 12:25 PM
Bent Bloke's Avatar
Bent Bloke Bent Bloke is offline
Senior Member
Site Admin
Join Date: Aug 2008
Location: Outer SE Portland
Posts: 179

Originally Posted by TimmyTwoPedal View Post
What mechanism does you work use for its gate?
Is it really a metal detector underneath?
Admitted I know very little about streetlights so I imagine that they use a variety of sensors, the question is if this one is being by them in any cases.
Do you know if the sensor you have at your work (I'm guessing a commercial version) is similar enough (or the same as) to a public street sensor?
It's buried in the concrete, so a little hard to tell.

I think the street sensors use electro-magnetic induction to detect the presence of a large object nearby. I assume the gate here at work uses the same method -- there is no pressure cable on top of the pavement, and no photo-sensor along side it.

On the street, you sometimes see painted symbols of a bike over the induction loops, to mark the "sweet spot" for bikes. Usually all you need to do is position your bike at that spot. You should be able to trip most of the lights by locating the induction loop cable (you'll see where the cut in the pavement was sealed), and stopping your bike over the loop. This should work even on signals that don't have the bike symbol marking, but not always. In those cases leaning your bike over should provide a larger target.

I've heard that it's not just positioning that counts, but the duration of the stop. A short stop over the sensor shouldn't trigger the signal, you need to stay there for a bit.
Reply With Quote