TRAFFIC LIGHTS

[Bahco]

hi Breezer

How do you wire them up and what is a relay

 

[breezer]

this is a relay

I chose this one 'cos its a nice clear picture.

when a voltage is applied to the coil (thing on the right) it becomes a magnet (electro magnet)

it pulls in an arm that you cant quite see (in the pic)

now the bit on the left of the pic is the contacts

NO C NC (in that order as you look at the pic)

NO is normally open

C is common

NC is normally closed

normal is considered when nothing is happening (no voltage on the coil)

so if you connect a meter between C and NC you will get a circuit

but nothing between C and NO (you always use C because it is common)

now if you put a voltage on the coil the arm moves the C contct from where it was to the NO contact

so if you now connect a meter between C and NO you will now get a circuit but nothing between C and NC

now you may ask what is the point of all this?

simple

the coil could be 12volts and the contacts could be switching 230 volts

You are in effect isolating one side from the other, there are lots of other uses and relays but they all work on the same principal.

in the case of the traffic light project the timer sends out 12v but at a very small current, not enough to light a 7w lamp. so i used a relay to switch a "big" load in comparison to the tiny load that switched it

But first of all you need to get clicky and make it up, it does need soldering, but it does come with instructions.

 

[thompsk]

for the more experienced try http://ourworld.compuserve.com/homepages/Bill_Bowden/page10.htm#ledlamp.gif
this will give you 4 sets of led traffic lights N,S,E & W
N & S working together counteracted by E & W ie N & S on red whilst E & W are green

 

[Spark123]

belive it or not, but one of the old boys in my local pub, well his dad invented the first traffic light!

Not thats got much to do with this subject.

Is that the one which exploded and injured a policeman?

If you knew anyone into electronics you could get them to build you a circuit like this:

Untitled

• Spark123
• 29 Sep 2008
• 1

The clock pulse can be created using a 555 circuit which someone spoke of earlier.

 

[tim west]

for the more experienced try http://ourworld.compuserve.com/homepages/Bill_Bowden/page10.htm#ledlamp.gif
this will give you 4 sets of led traffic lights N,S,E & W
N & S working together counteracted by E & W ie N & S on red whilst E & W are green

Trouble with that circuit is it looks like it works in an american way with the Red led on at the same time as the Green unless its supposed to be a bi colour led(red +green equals amber, still wouldnt work right )? It does say 6 leds though and looks wired that way

Heres one that looks more like the UK traffic lights

bottom of page:

http://www.doctronics.co.uk/4017.htm

 

[NewOrder]

I used to built simple two way sequencers as a kid. I uses a 555 timer and put a POT between two of the pins (can't remember which) in which i used to control the speed. I then used 10mm LEDS to make effective disco lights out of.

You could easily use this for basic red/green lights but the circuit I used is in a book and is copyrighted .

All the three way ones all seem to use the Philips 4017 counter and these circuits a little bit more complex.

The Vieleman kit mentioned seems to be the best bet.

Have fun breathing in all the fumes of those burnt ICs .

Edit and people stop being pussy's and use PIC and that old 486 PC you have in the loft .

 

[tim west]

Edit and people stop being ****'s and use PIC and that old 486 PC you have in the loft .

I prefer the propeller microcontroller

 

[Bahco]

Thanks for all the replies even though I can't understand a word of it!

Been into Maplins today for advice and they couldn't help. The nearest I seen was a 4 light disco light set but my little one wasn't impressed.

If anyone can help or spots one for sale please post it here.

 

[RF Lighting]

Would you like me to assemble a velleman kit for you?

 

[breezer]

looks like you will have to make your own

 

[Bahco]

Would you like me to assemble a velleman kit for you?

Very kind of you to offer Rob. Shame you are not in my neck of the woods.

If you could talk me through it in English I would be grateful.

 

[breezer]

i would suggest you buy one first, its amazing how easy they are to assemble.

it really does have a section telling you things like

a 2k2 resistor has red red red bands

a 4k7 resistor has yellow violet red bands

the pcb has drawings of which one goes where

you will need a soldering iron and solder, that is not included

 

[Bahco]

Have you a link where to purchase pls Breezer.

 

[NewOrder]

Soldering is the skill though, I have built many complex circuits on breadboards and can understand the circuit diagram to a motherboard, but I cannot solder very well.

The ICs have gaps of a tenth of an inch if I remember correctly, this means soldering them requires a bit of skill, I have done it before but it is a little fiddely.

After reading this thread I have a sudden urge to go to Rapid Electronics and start melting some IC's again .

PS Has anybody applied 24v to a 3.3v LED, the smell is very very unpleasent : and probably toxic. Or there that time I blew up a load of darlington pairs, it took hours to get rid of the smell, my teacher was not impressed .

 

[tim west]

Have you a link where to purchase pls Breezer.

http://www.twenga.co.uk/offer/52661/7778376210991319563.html