How to make a speed meter to stop cars from speeding?

Ok folks, I live along a street where people come blasting through, and I want it to stop considering there are kids who kindof like to play on it.

Here is born my idea: A speed meter that sits in my yard.

If it senses a car going faster then about 30 MPH, it will automatically set off a siren, scaring the crap out of people and making them slow down.

I don't want to hear about how this may/may not be illegal, I'll go to jail if its for the sake of saving our kids lives.

So I was thinking about how to do this.

An Arduino might work...but I would have to find some type of speed meter to use as a serial device for the Arduino, and after I did this, it'd be pretty easy. Just wire up a siren to a relay on one of the Arduino's outputs and away I go.

Anybody know where I could find a speed meter that will work with the Arduino?

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acidbass7 years ago
 nails or tacks on the roads or speed bumps
DO NOT consider the nails/tacks approach. Your neighbors will string you up by your gonads the first time a kid steps on one of those.
 i was thinking a different approach for placing them but dont worry about it 
Re-design7 years ago
You can buy a radar gun for about $100. Set it to only trigger at 32 mph.   Then make your siren read the gun either by photo cell or what ever method and sound off.

And it's stupid to go to jail over making this.  It may not even help the cause where getting neighbors together enmass and DEMANDING from the city council more protection will get more results.  Band together and get an attorney to help you in necessary.
orksecurity7 years ago
Toy radar guns are available, I believe.

Or you could try to set up two beams that get interrupted and measure time between them.

Or you could point a camera at the street and try to do image analysis on successive frames.

HOWEVER: I suspect your neighbors will get on your case about noise pollution VERY quickly, especially if this thing ever has false positives.

Strong suggestion that, instead, you tell your local police that there is a problem, ask them to set up one of their official advisory/reminder signs, and ask them if they'd consider doing some additional patrols for a while and writing some tickets. In many areas, that's by far the best solution.