A little electronic widget that sits on the dash of your car and reads traffic lights.
There's a lens/camera and a microprocessor that looks for red light above and in front. When a spot of red remains constant for thirty seconds, and then is replaced by a green light just below it, the widget beeps/flashes/honks the horn at the driver in front/activates full throttle.
The logic is simple enough that it could be done with a couple of sensors and a transistor or two, but chips are cheap.-- baconbrain, Feb 07 2013 //the widget beeps/flashes/honks the horn at the driver in front/activates full throttle.// Well, okay, as long as my car is the only one with this feature.-- DIYMatt, Feb 07 2013 OMG. [Loris], I apologize. I accidentally clicked delete on your comment. I retrieved:
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It will fail to function if the driver is in a filter lane - as the red light will still be shown.
As described, the system doesn't necessarily account for whether the vehicle is in motion, so would activate regardless of whether the car was actually waiting at the junction.
Other coloured lights (for example christmas lights) may activate the system.
— Loris, Feb 07 2013
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Sorry.-- baconbrain, Feb 07 2013 This idea will work an a smartphone app, if you don't mind having the camera looking up and out. (Maybe a little periscope?)
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As for use in the UK and other civilized countries, I admit I was just thinking of the USA and its lights. I'd say a little more programming could get around most sequences. I do not know what a filter lane is, nor how it is lit.
I envisioned the detector having a fairly narrow sweet spot/strip, so as to detect only lights directly ahead, the ones that relate to the lane the car is in. The car will have to be pointed straight, of course, and the detector installed carefully.
The sweet spot would allow for the car to be fore-and-aft a bit, but I was thinking of alerting the driver only when the car is first in line, not 'way back in the pack. So it wouldn't be that large, and would reduce errors, again.
As for the car being in motion, I meant the "spot remains constant" bit to refer to that. A streak of red moving across pixels would show the car is in motion, while a small set of pixels staying red for some time would show the car is stopped.
I also addressed the position of the traffic lights, by looking for green appearing relative to where red was. Yes, Christmas lights might activate it, but the chances are reduced.
And the bit about honking and racing ahead was meant to be silly. I'd say a simple "ding" for the driver would suffice, after which a visual confirmation of the traffic lights would be legally required.-- baconbrain, Feb 07 2013 Sounds like a way to complicate life for traffic officers. Which is no bad thing.-- UnaBubba, Feb 08 2013 s'okay, never mind.
In the UK a filter lane is one for turning left or right - vehicles get to go a bit earlier than those in lanes going straight on. A green arrow lights up while the red is still shown.
My earlier comment also mentioned that pedestrian lights have a different sequence (red, flashing amber, green) - the standard sequence is red, red+amber, green.
So the basic points were that the logic would need to be a bit more complex than proposed, and that there may be some issues with calibration. If you want to inform the driver when they're close to the junction then you need to scan quite a wide angle for lights. At complex junctions I sometimes find it quite hard to tell which lights actually relate to the current position.-- Loris, Feb 08 2013 random, halfbakery