how to build a speed camera or speed detector?

[Brendan Humphreys]

I live on a very straight suburban road which has an unfortunately
gained a bit of renown as a good racing strip. It's a 50 zone, but at
night we regularly get cars and motorbikes flying down the street at
more than twice that speed. Having now reached a certain curmudgeonly
age (and having small kids), I'd like to really deter these
speedsters. The speeds some if them reach (often in groups) is
freaking dangerous on a suburban road.

The neighbours and I have called the police a few times, and they send
a patrol down, but the culprits are too smart to do too many laps and
have long gone by the time the cops arrive.

What I'd like to do is beat these people with data. I'd like to build
something that inconspicuously (and inexpensively) detects speeding
vehicles and logs the time and day. I'd like to build up enough data
to pick patterns of when a police radar might be most effective. I'm
hoping I can present a nice graph to the local cops, and convince them
to position a radar there at the right time. Yes, I'm a complete
killjoy.

I'd like to solve this inconspicuously, probably by something strapped
the the street pole closest to my house (within wifi range).

Thoughts, anyone?

Cheers,
-Brendan

[Nick Johnson]

The simplest solution that springs to mind - though I'm not sure how well it would work - is to use an ultrasonic transducer. Take readings at fixed intervals and integrate to find the speed.

-Nick

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[David Lyon]

I think he's talking about 'speeding' cars..

Doplar effect may be one way to go. That's a simple microphone and some
software but I haven't located it. They use it on the M5.

Of course, a video recording add persuasion too.

[David Lyon]

Here's an arduino library for sound frequency measurement:

 - http://interface.khm.de/index.php/lab/experiments/frequency-measurement-library/

[Max Nippard]

I bought a hot wheels radar gun and left it at the space for general hacking. 

It does work on 1:1 scale cars and bike and has a 1:1 and Hotwheels scale switch. 

You're welcome to use it as part of your project. 

The vital parts are fit in a cylinder a little smaller than a Pringles can. 

On Sunday, August 5, 2012, David Lyon wrote:

Here's an arduino library for sound frequency measurement:

 - http://interface.khm.de/index.php/lab/experiments/frequency-measurement-library/

[Gav]

Simplest way is an 'amphometer'. Have two pairs of light beam sensors that can detect when a car passes between. Use the known distance between them and the time to move between the pairs and you can calculate the speed. 

Pretty easy to set up with laser pointers or IR sources and a light level sensor. The best bit is that unlike radar guns it doesnt require calibration.  

Cheers. 

Gavin

On Sunday, August 5, 2012, David Lyon wrote:

Here's an arduino library for sound frequency measurement:

 - http://interface.khm.de/index.php/lab/experiments/frequency-measurement-library/

[Max Nippard]

 Another simple option hardware wise, would be a web cam or ip cam and security software that lets you set multiple gates or zones in the image as triggers. 

[David Lyon]

On Sun, Aug 5, 2012 at 9:18 PM, Max Nippard <mnip...@gmail.com> wrote:

 Another simple option hardware wise, would be a web cam or ip cam and security software that lets you set multiple gates or zones in the image as triggers. 

Something like this may work, but depends on the position of the camera.

Lot's of in-car reversing camera's have a measuring-grid simply superimposed over the video.

It's a cheap software trick.

If you could build a system with the same super-imposed distance grid, you could start
off by measuring time manually then work up to a more automated system using something
like OpenCV.

[Jason Lewis]

How about writing to the council and explaining the issue and asking
them to put those speed measuring devices on the road? You know the ones
with the rubber tubes?

Which incidentally I saw the workings of at my old work. They have these
pressure sensors in them that detect the change in pressure when a
vehicle runs over the pipes.

Jason

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[Brendan Humphreys]

Thanks for everyone's suggestions.

The amphometer sounds easy, except that I need something on the other
side of the road to produce the beam. Or maybe I could design
something that looks for reflected IR off the car as it passes by, so
I can keep the system on one side of the road...

The video processing route looks interesting, and definitely the
simplest hardware-wise (although I'd need to weatherproof a wifi
webcam). The software on the other hand looks epic :-) OpenCV looks
like it could be an all-consuming odyssey. Still, you'd get compelling
footage to back up your case.

Doppler is interesting also, as is the toy radar gun. might have to
try that out to see what range it has.

For anyone interested, I found this thread covering similar territory
(with similar motivations):

http://forums.makezine.com/comments.php?DiscussionID=6689

@Jason I'd rather not involve the council at this point. My experience
with council is that if they do anything, they do what they have the
power to do, which is install speed bumps or chicanes or something,
which I'd be against.

Cheers,
-Brendan

[Max Nippard]

The amphometer could use a reflector or reflective tape on the far side of the street and a light sensor at the end of a length of black pipe. I build a camera trigger like that with cheap laser pointer that worked over many meters. 

[Kris]

Hi, Not a very techie answer but you may not want to go down the techie path, anything you submit will then have to be reverified (unless you are submitting evidence of a crime (which a video of speeding cars would be), then you would need, at the very least, to provide a statement. However, if you write a letter addressed to the Commander of your Local Area Command this then gets given to the Crime Manager who determines its priority and acts accordingly. When acted upon, police get together with the local council (or roads and maritime services if they own that road) and visit the site to determine what can be done. There are three things they look at: Engineering, Enforcement and Education. Obviously you are leaning toward the enforcement side of things, and if its hoons you can pretty much assume that they know the road is 50kph but choose to ignore that instruction (so education is not the problem). However I'm told that if it's a nice wide straight road, in an area where this is a persistant problem, the police may well ask council to provide an engineering solution, and this could mean humps or a number of other measures. Given money comes from the same pot, government looks at what will give the best outcome for the least cost. If police are constantly setting up lidar traps but its not reducing the problem overall then engineering is often a more cost effictive solution.
Kris

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Brendan Humphreys <brendan....@gmail.com> wrote:

[Dr Ada Not-a-fruit]

On Aug 5, 9:14 pm, Max Nippard <mnipp...@gmail.com> wrote:
> I bought a hot wheels radar gun and left it at the space for general
> hacking.
> It does work on 1:1 scale cars and bike and has a 1:1 and Hotwheels scale
> switch.
> You're welcome to use it as part of your project.
> The vital parts are fit in a cylinder a little smaller than a Pringles can.

For slightly more hackable,

http://www.siliconchip.com.au/cms/A_107875/article.html

[Terry Dawson]

On Sun, Aug 5, 2012 at 8:52 PM, Brendan Humphreys
<brendan....@gmail.com> wrote:

> What I'd like to do is beat these people with data. I'd like to build
> something that inconspicuously (and inexpensively) detects speeding
> vehicles and logs the time and day. I'd like to build up enough data
> to pick patterns of when a police radar might be most effective. I'm
> hoping I can present a nice graph to the local cops, and convince them
> to position a radar there at the right time. Yes, I'm a complete
> killjoy.

I think trying to automate the process will add a lot of time and
possibly expense to your project.

I think I'd consider using an inexpensive Wireless IP video camera and
streaming it to disk, then just manually excerpting highlights out
later.
Let your neighbours know what you're doing and get them to keep a
diary of dates and time to make the excerpting process easier.

Many IP video cameras support motion detection, so you could posisbly
rely on that if you really want an automated approach. I bought a
couple of cheap (~$70) wireless IP video cameras to much around with
recently and they'd probably be good enough for the job.

I'd consider painting a couple of lines on the road a known distance
apart or somehow setting up a couple of landmarks or other reference
points to use as a reference for calculating speed.

Terry

[Sparks]

If you have an existing household security system, another option is to 'extend' it's view by placing (low-cost IR) security cameras between equidistant points. If you have a couple of like-minded and equally discreet neighbors, the data collected will suffice to 'make a casual observation' (not a formal report) to local enforcement.

As to the actual medIa, there are several free cloud servers. Depending on the length and type of media measured, you could simply subscribe to additional (free) space as needed. And, most every eMail provider automatically dedicates a lot of media storage space.

Cheers-Sparks

[David Lyon]

Interesting Radar Kit Ada,

This is a Doppler kit in Akihabara for about $30

http://translate.google.com/translate?hl=en&sl=ja&u=http://akizukidenshi.com/catalog/c/ckit3/

[Ryan Leach]

before getting over complicated, I'd just have a camera flash going off, if speeds are too high, may be just enough to deter them. 

[David Lyon]

Or even an RGB strip driven by a WS-2801 that can flash blue and red
consecutively.

Mount that to a signpost before the cars come around the corner and it
may slow them.

Even just the standard RGB strips can function like this, I know, I
made one once.

[Madox]

I believe that may be illegal.

[David Lyon]

On Mon, Aug 6, 2012 at 1:17 PM, Madox <mado...@gmail.com> wrote:

I believe that may be illegal.

I only thought mounting them in cars was illegal. Which isn't what I
was talking about.

They can come arrest me for having a coloured LED collection. I
don't care.

[David Lyon]

I was thinking actually of an LED-Tshirt:

 - http://www.youtube.com/watch?v=IlYNIEj0M1U

[David Lyon]

Are flashing LED T-shirts illegal? I have no idea...

[Tim]

I think it's going to fall into the 'impersonating an officer' category. Especially since that's what you are actually aiming for....

I think OP would be better off rallying and approaching council and attempt to get the speed limit raised to 100kph for that section, then no-one would be speeding :)

Tim.

On Mon, Aug 6, 2012 at 2:02 PM, David Lyon <david.lyon...@gmail.com> wrote:

Are flashing LED T-shirts illegal? I have no idea...

[Jason Lewis]

That's what I like about you Tim, always thinking outside the box ;)

Jason

-- 
Jason Lewis
http://emacstragic.net

[Franc Carter]

On Mon, Aug 6, 2012 at 2:05 PM, Tim <coo...@gmail.com> wrote:

I think it's going to fall into the 'impersonating an officer' category. Especially since that's what you are actually aiming for....

I think OP would be better off rallying and approaching council and attempt to get the speed limit raised to 100kph for that section, then no-one would be speeding :)

The cynic in me thinks that people will then do 200km/h ;-(

 

Tim.

On Mon, Aug 6, 2012 at 2:02 PM, David Lyon <david.lyon...@gmail.com> wrote:

Are flashing LED T-shirts illegal? I have no idea...

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[David Lyon]

As a pedestrian, I find the most dangerous drivers aren't the
ones with hotted engines that you can hear coming from a few
streets away, but those driving larger cars with practically silent
motors, that refuse to use indicators to go round corners so it's
impossible to judge if you are going to be hit until the car is
within a few feet of you.

[Jaz]

Indication is a sign of weakness!

[Kris]

To the flash? I think it might be too, at the very least your giving an explanation to the person who crashes into your house (or worse) other than speed

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Madox <madox.net@gmail.com> wrote:

I believe that may be illegal.

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[David Lyon]

It may not be so difficult in OpenCv. There's some functions for
movement detection.

If something moves in the frame, you get a rollback and can track it from then.

You'd need to have the camera mounted at a fixed point and do distance
measurements on the ground with markers.

Its doable I think.

Later I will find the python code for it.. I know I have used it..

[David Lyon]

This worked when I tried it:

 - http://blog.appdelegateinc.com./category/Experiments.html

[Jake Anderson]

On 05/08/12 20:52, Brendan Humphreys wrote:
> I live on a very straight suburban road which has an unfortunately
> gained a bit of renown as a good racing strip. It's a 50 zone, but at
> night we regularly get cars and motorbikes flying down the street at
> more than twice that speed. Having now reached a certain curmudgeonly
> age (and having small kids), I'd like to really deter these
> speedsters. The speeds some if them reach (often in groups) is
> freaking dangerous on a suburban road.
>
> The neighbours and I have called the police a few times, and they send
> a patrol down, but the culprits are too smart to do too many laps and
> have long gone by the time the cops arrive.
>
> What I'd like to do is beat these people with data. I'd like to build
> something that inconspicuously (and inexpensively) detects speeding
> vehicles and logs the time and day. I'd like to build up enough data
> to pick patterns of when a police radar might be most effective. I'm
> hoping I can present a nice graph to the local cops, and convince them
> to position a radar there at the right time. Yes, I'm a complete
> killjoy.
>
> I'd like to solve this inconspicuously, probably by something strapped
> the the street pole closest to my house (within wifi range).
>
> Thoughts, anyone?
>
> Cheers,
> -Brendan
>

I'd suggest an air rifle and a steady hand but that would probably get
you in trouble.
Fixed red/blue flashing lights aren't illegal but will wear off in
effectiveness quickly, particularly after they are stolen or removed by
council.

[David Lyon]

In America, as a teenager, we were allowed to throw eggs
at cars..

[David Lyon]

http://www.graysonline.com/lot/0058-5003924/construction-scaffolding-and-formwork/traffic-flow-equipment-inc-4-x-steel-traffic-bollards-ea-approx-600mm-h

[David Lyon]

For $13 I noticed this part which might be fun to play around with:

 - http://www.aliexpress.com/product-fm/462470926-Doppler-Radar-Microwave-Motion-Sensor-Wireless-Module-Free-Shipping-wholesalers.html

[David Lyon]

The best reference on this product is here, with datasheets and
application notes:

 - http://www.openimpulse.com/blog/products-page/sensors/hb100-microwave-sensor-module/#more-94

Interesting reading.