Please help to design a 4 way traffic light controller

[Bloodninja]

Hello everyone,

I need help designing a 4 traffic light controller for my graudation project, right now I chose to use the decade counter ic 4017 but I have no clue on how to create a cascade connection with other counters while keeping the Red light on for others...

your help is greatly appreciated...

 

[gary350]

This is very easy. Go to ebay do a search for a SLC 150 and a hand held programmer.

**broken link removed**

In the past these were selling for $15 each. The is an old out dated unit. Most people use the new models so the old one were selling cheap but the people that have them now think they are a gold mine and want big $$$ of them. Sellers think it is cheaper for the buyer to pay big money for this rather than to swap to the new unit and pay to have a new program written that could cost $5000.

The SLC 150 is a very simple programmable controller. There are 4 units, one is 120 volts AC, one is 12 or 24 VDC. The AC units operate by hard wire switches or contacts. The DC units operato by prox switches. There is also an expander unit which is used with another unit it is worthless all by itself. Each unit has 20 inputs and 12 outputs.

With the hand held programmer you can program them to do anything you like. You can make a 4 way traffic light that is activated by timers sensors in the street. You can wire the lights in your house to go on and off with the sun, the clock, sound or what every you like. There is no end to what this unit can do.

If you buy a DC unit you will also need to buy a DC power supply. The hand held programmer works on all 4 of these units. Since the people selling the old units seem to think they have a gold mine you might do better to buy a newer Allen Bradly SLC last time I bought one 5 years ago new price was $99 for the AC unit and it has more inputs and outputs than the old units.

They are very easy to program do a search for SLC 150 instruction manual online.

 

[Mike odom]

Hello everyone,

I need help designing a 4 traffic light controller for my graudation project, right now I chose to use the decade counter ic 4017 but I have no clue on how to create a cascade connection with other counters while keeping the Red light on for others...

your help is greatly appreciated...

If you're attempting to use multiple 4017s and try to hold one or more off while another is counting, you'll need 'glue' logic, so it would be easier to just build a 'state generator' with one counter and logic.

If you look at the functions of a 'simple' intersection (N/S E/W red yellow green, no left turns), then you can do this with just one counter. The apparent states are:
1) N/S go, E/W stop approx 30 seconds... counts 10
2) N/S yel, E/W stop approx 6 seconds... counts 2
3) All Stop... approx 3 seconds.... counts 1
4) E/W go, N/S stop approx 30 seconds... counts 10
5) E/W yel, N/S stop approx 6 seconds... counts 2
6) All Stop... approx 3 seconds.... counts 1
The counts are based on the ratio of the smallest unit (all stop) to the largest unit (go).
The 'state' logic can be done with (1) 4017 decade counter/decoder, (1) quad nand, (1) hex inverter (scmidt trigger), (1) quad OR, and (2) Dual D f/fs.

Inputs to the circuit: 1/3 Hz clock, Power on Reset signal.

This will yield the following signals: E/W, N/S (-E/W), YEL, -YEL, ALL (all stop), -ALL.

There will be some additional logic to turn on the outputs from the above signals (decode the above signals to determine which outputs to turn on. Either some nands, nors, ands, ors or (2) octal decoder chips (like the 74c138).

Let me know if this is the path you want to take, and I'll continue to help you develop the schematic.

 

[Mike odom]

Also there will be the output drivers. For that we need to know what you're planning to drive... LEDs or Lamps, and the voltage/wattage of them.

 

[3lectrokid]

For a 1 chip solution look at a PIC ic or an Atmel controller

 

[mbarazeen]

see the bellow post same topic was discussed and many sugestions and diagrams were poasted. read it fully.
i have posted a diagram using 4017(reply #14), may help you.

https://www.electro-tech-online.com/threads/traffic-light-help-sos.99450/