Remote Temp Traffic Lights -- sync & design

Hi All,

I would like to get some of your thoughts / comments on a traffic light project I want to build.

I want to create 2 units (one at each end of a section of road) and have them work in sync, so that I can accurately show a countdown time on each unit that will display the remaining time to "move" (when light is green) versus time left to "wait" when you are at the end where the traffic light is red.

I was thinking of using Xbee radios for the units to talk to each other, but I am not sure if that is the way to go.

Should the design be that there is one "master" that just sends commands to the slave to turn on the proper light and to initiate the countdown timer ? I am thinking of running these units with big "car type batteries" so I will want to squeeze all the power I can - so sleeping the processors when possible.

If this all works, I would also add a handheld remote to stop the countdown and turn all the lights red and stop traffic flow in both directions. The user would press another button to re-start the automatic mode after having disable it.

thanks.

display the remaining time to "move" (when light is green)

Does that mean what I think it means, that is it's displaying how much green time is left? That scares the cr@p out the traffic engineer in me (I was one once, just after graduation as a civil engineer) since it will encourage putting pedal to the metal to squeeze through while there's (not really) time.

That's a really good point !! I would just turn off that display and keep it active only when light is red.

I am also thinking of having the yellow light active for 1 or 2 seconds on both sides, just before the traffic flow changes direction. In Quebec, we don't usually have a sequence that goes red, yellow, green (we just have green, yellow, red) but I saw that in Iceland and really liked it. It suggested to me to get my car in gear, and stand by to start moving.

Is this a hobby thing or you hoping to sell this ?
Wet blanket time :
This worth a read to see the opposition. I imagine development/build/ approval costs to be high ?

hammy:
Is this a hobby thing or you hoping to sell this ?
Wet blanket time :
This worth a read to see the opposition. I imagine development/build/ approval costs to be high ?

Technical standards

I remember seeing quite a few of these things in Germany when road work had closed one lane on a corner. Lots of corners in Germany. Even seen a few in operation in the US. Otherwise a flagging crew has to be on-site 24 hours a day.

Paul

I would have one as the master - the remote with not much smarts so to speak - have some sort of handshake so that each knows the other is running properly with some sort of failure mode if one dies

With a 'car' type battery - lots of capacity - I would use a solar panel to keep the battery charged - lots of 12 volt panels out there - just plug and charge

The method i’ve seen as above, puts the Red on at one end held for x seconds to allow traffic to drain from the road BEFORE the Green is opened up,at the other end, and vice versa.

You can also see the the same lights applied to narrow one-way bridges.

Paul

Thanks for the replies. Some responses below.

This is for me to "play and learn" electronics, radios comms, etc.

With the amount of road work being done all the time in Quebec, there is a company that makes them....

They sell for roughly $9,000 CAD.

Yes, I agree that there needs to be careful planning of the time sequence to allow for the traffic to clear before reversing direction.

The Quebec website I found even has a version with some sort of GPS linking instead of radios.
That is most likely too complicated for me - I know nothing of how GPS works, I would stick with Xbee radios they seem simpler.

I was thinking car batteries imagining they would provide longer life (usage) but yes a solar panel to charge would be a good "add-on" if I can get the basic system to work to begin with.

Any thoughts on how to sync the units at the start of the day (or when they are 1st powered up) ?
Would the sync need to be updated during the course of the day ?

Do I need to think of syching or does the "master" unit just send the commands to the slave unit, and in turn, it just turns the proper light on or off ? In this scenario how to I have the slave countdown the seconds : its own internal timer or it receives the pulse of the time to display on the digit leds ?

thanks.

Hi,
Look up "Deep Cycle Batteries", car batteries are designed to be kept at full charge most of their life by a car alternator.
Deep Cycle are designed to be discharged and recharged.

Most of your energy will be used on the display even if you use LED type, you will be battling against varying ambient light levels

I would forget the timer display, that will only encourage drag strip mentality on STOP to GO, and impatience and speed when GO to STOP. Good old RED, AMBER, GREEN would be sufficient.

Also make the light assembly "Serviceable", you will find they are good targets for rocks, cans and BULLETS.

I have recently had six panels from a mobile street sign on my work bench, each had numerous .22 bullet holes in them and we have strict gun licensing in this country. (Probably why it was only 22 calibre)

What sort of range are you thinking of, and be prepared to put a proper aerial at each end of the control stage.

Placing a sensor on each unit to see if there is traffic stopped at the signal might be good idea. Like these below.
MPB3200-500x500.jpg

Tom.... :slight_smile: