# Need help for designing circuit for LEDs of car

#### moonnightingale

Joined May 22, 2010
9
I want to simulate a circuit of car in a software. There are three lights on each side of a car. when the car is given instruction to turn, these lights operate in a sequence. First of all inner light then inner two and then inner three and this procedure is repeated. For both right turn and left turn it follows this procedure.
There is also a emergency input (Hazard light) which flashes all six LEDs as on/off/on and so one
I have to design a sequential circuit for above stated
Can u tell me the components which will be used for this circuit
Thanks

I am using 4017 IC but this IC swiches on only one LED at a time
what i need that first LED glow, then first two and than all three for the turn
which IC i should use

#### SgtWookie

Joined Jul 17, 2007
22,210
It's one thing to simulate it; another to actually attempt it with a real vehicle.

You know that such modifications on actual vehicles are illegal in many parts of the world, right?

#### moonnightingale

Joined May 22, 2010
9
It is my assignment,
I just have to simulate it in proteus.
Can u help me for its circuit diagram
I will be grateful to you for this

#### SgtWookie

Joined Jul 17, 2007
22,210
We will have to wait for a Moderator to approve or disapprove of this discussion, along with moving it to the correct forum, "Homework Help".

Automotive modification topics are not allowed on this site. However, academic exercises are OK. It must be understood that such simulations will be very simplified, and will not perform as such in a real automotive environment.

#### moonnightingale

Joined May 22, 2010
9
Ok i am waiting anxiously for circuit diagram.

#### SgtWookie

Joined Jul 17, 2007
22,210
We won't design it for you.

You need to start figuring out what logical states that you need to accomplish the objectives set for you.

#### moonnightingale

Joined May 22, 2010
9
Ok that i know but i am confused about 4017 decade counter
this decade counter has ten outputs which go HIGH in sequence when a source of pulses is connected to the CLOCK input and when suitable logic levels are applied to the RESET and ENABLE inputs.

What i want that first of all First LED glow, then second should glow while first one remain on and when third LED Glow, initial two LEDs remain on

Which IC should i use for that

#### SgtWookie

Joined Jul 17, 2007
22,210
Maybe you should consider using OR gates.

Why don't you start off making a truth table?

#### #12

Joined Nov 30, 2010
18,210
You might use diodes to route the second output to 2 LEDs and the third output to 3 LEDs, and so on.

#### SgtWookie

Joined Jul 17, 2007
22,210
You might use diodes to route the second output to 2 LEDs and the third output to 3 LEDs, and so on.
This approach doesn't work. Another member tried it a couple of years ago. I helped them solve their dilemma.

I don't want to just hand the solution to the student. They need to do the work, otherwise they won't learn anything.

#### #12

Joined Nov 30, 2010
18,210
I guess I did an Oops.

#### moonnightingale

Joined May 22, 2010
9
Ok i will make th truth table this way
Input output
0 0 0 0 0 0 0 0 No light on
01 0 0 0 1 1 1 For right turn
10 1 1 1 0 0 0 For left turn
11 1 1 1 1 1 1 For Hazard light

Am i right in making Truth Table
The question is attached. Plz help me how to start it

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#### moonnightingale

Joined May 22, 2010
9
What i have understood uptill now that first of all i will make truth tables and state machine and then design it in verilog.
Then i will see RTL schematic in Verilog and then based on that schematic, i will make circuit in Proteus and simulate it

But this procedure is too lengthy . Can i go directly to proteus and simulate it

Plz help me

#### bertus

Joined Apr 5, 2008
20,461
Hello,

This looks like a valid homework assignment.
Please NEVER try to make it in real life.
The safety can NOT be garanteed.

Bertus

#### moonnightingale

Joined May 22, 2010
9
Can any body help me for this circuit

#### SgtWookie

Joined Jul 17, 2007
22,210
You must be located in a part of the world where the time is very different from where I live. When you made your "truth table" post, it was 11:35pm my time, and I was on my way to bed. Now it is 6:40 on Sunday morning.

As for your truth table, you have not implemented it as the problem statement describes.

How many inputs does the problem statement say that you will have? Or, what are the functions of the inputs, and what are their relationships?

What does the problem statement say about the permissible states of these inputs?

Once you correct the truth table, you can start on the state diagram(s).

It might be easier to start off making a state diagram for each input, and what the lamp(s) condition is for each state.

#### Georacer

Joined Nov 25, 2009
5,182
This can certainly be solved through a sequential circuit but I think it's an overkill for this exercise.

I liked the idea of the ring counter with the OR gates (as Sgt suggested) and I 'd like to use this instead.

We have three inputs, a ring counter rigged to count from 0 to 2 and a clock.

Doing the right logic comparisons and using three 1-to-2 DeMUX you can select the output of the ring counter to either block it completely, send it to the left lights or the right ones. For the hazard condition you can use another DeMUX to pass the system clock directly to the flashing lights.

Do you understand what I 'm trying to say?

#### moonnightingale

Joined May 22, 2010
9
No i am still trapped, i dont know how to start the circuit.
Can some body make a circuit and send to me. It is too difficult to understand for me

Atleast tell me the components which will be used in this circuit. Actually my cousin gave me this task for learning purpose, and he gave me broader guidelines to implement it. He has given me next 20 days for this. He has given me challenge to solve this and if i will do it, he will give me his car for one day for picnic
So plz help me

Last edited:

#### Georacer

Joined Nov 25, 2009
5,182
We will not do your work for you under no circumstanses, especially since you don't show any effort from your part by posting some kind of premature schematic.

Let's take things one by one. Can you post the circuit of a ring counter that counts up to 2, with its three first outputs ORed together in order to display one, then two and finally three LEDs lit up?

Also, do you have to desing your own clock, or will that be given as an input? Search the net for "555 clock" and come up with a design. I think Bill's design will work too: