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princejude
Joined: 07 Aug 2010
Posts: 72
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| Sensors for Traffic Light system |
 Posted: Mon May 07, 2012 5:31 am |
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| Am about to design an intelligent traffic light controller. This will be a T-junction traffic light control and I will like to sense which side of the road has more vehicle waiting to pass. What type of sensor will I use to sense the number of vehicles at each side of the T-junction. Will ultrasonic sensor be ok, and if yes, what type? Is it possible to interface up to 6 or 9 pairs of ultrasonic sensors in one chip and that same chip will also control the traffic light operation. And if ultrasonic is not ok, what sensor will I use. |
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SherpaDoug
Joined: 07 Sep 2003
Posts: 1640
Location: Cape Cod Mass USA
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| Posted: Mon May 07, 2012 6:02 am |
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I looked into such matters a few years ago and found the industry has been using inductive loops (like a metal detector) to sense cars for decades, but new installations have switched to using video.
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The search for better is endless. Instead simply find very good and get the job done. |
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princejude
Joined: 07 Aug 2010
Posts: 72
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| Posted: Mon May 07, 2012 7:43 am |
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Quote:
| Quote: | | the industry has been using inductive loops (like a metal detector) to sense cars for decades, but new installations have switched to using video. |
Are you saying that ultrasonic sensor will not be possible ? |
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temtronic
Joined: 01 Jul 2010
Posts: 9221
Location: Greensville,Ontario
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| Posted: Mon May 07, 2012 7:49 am |
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No, he's saying that of all the option the industry has available, video camera technology seems to be the way it is done.
You can easily use ultrasonics if you want to.Even IR,microwaves,inductive(wires in road,tar shows where they are) can be used.
the choice is yours !! |
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asmboy
Joined: 20 Nov 2007
Posts: 2128
Location: albany ny
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| Posted: Mon May 07, 2012 8:07 am |
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| Quote: |
Are you saying that ultrasonic sensor will not be possible ?
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He did not say it but i will!!!
Ultrasound is probably useless
as is doppler microwave detection too( unless very carefully aimed).
In-ground loops CAN broadly sense the amount of traffic load above them but are biased towards how well coupled the loop is, to the metal mass of the vehicle load above it - so a large truck with its frame high above the loop might equal only one small car close to the ground etc etc but the basic detector will still tell if there is ANY metal vehicle above the loop and be totally (or close to it) insensitive to weather conditions.
You will spend a LOT of effort on the analog properties of the loop circuitry and near nothing on the pic code though.  |
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