How do Traffic Lights Notice Bicyclists? This totally unrelated reply raised my question about traffic lights.

I am starting to think that my chinese head lamp is a magical instrument, every time I go near traffic lights they turn green. It is hilarious to drive in heavy-traffic and just that you get green lights! Perhaps just a placebo feeling so I want to know how your traffic lights behave to you when you are driving within other traffic? How do they notice you with/without lights?

Well, I need to explain how it works. I have head lamp with blinking white light and particularly when it is very dark, the traffic lights are clearly programmed somehow to detect the intensity variation of lights and then turn green. I have heard that emergency cars show some kind of special light to turn lights green for them. But I suspect whether the head-lamp contains some special light, it was the cheapest model I found from eBay.
There are two basic types of intersection detection systems out there:


Induction loop coils:
These are basically a metal loop or figure 8 embedded in the pavement, and will detect anything that conducts electricity. Much like a metal detector, such as you might walk through at the airport. Sometimes you can see lines carved into the road surface. Getting your wheel over the lines will help you get picked up.
Cameras: You may be able to see the cameras, even.  These are generally black and white cameras that are programmed with areas they pick up for each lane and do some sampling things and if the samples look different than the "baseline", that's a detection. If your headlamp is helping, this is the type of detector in use at that intersection. A bright light will definitely be picked up at night. Light clothes that contrast with the color of the road surface will also help.