Hello everyone! Today I will show you step by step that how you can make 4 way automatic traffic light signals using Arduino and some very simple and easily available components. For better understanding, I would like to recommend you to watch this video before you start making.

Step 1: Introduction and Working:

This is a very simple version of DIY 4 way traffic signal lights using arduino. I am using 12 pins of arduino as output to drive all signals. there is no rocket science, simply i make them on and off in a sequence with some time delays in arduino code.

For poles, i decided to use 7 LEDs for each colour. We can not drive this amount of LEDs directly through arduino. So i used BC547 Transistors to drive them.

Step 2: List of Components

List of Components for Control board:

R1-R12 = 220R

U1 = Arduino NANO

U2 = LM7805CD

DC12V = DC-005

LEDs = 5mm RED, GREEN, YELLOW (4 each)

Female Header = 2.54mm

List of components for Pole PCBs: (For 1 pole)

Q1-Q3 = BC547

R1,R3,R5 = 150R

R2,R4,R6 = 330R

R7,R8,R9 = 1K

LEDs = 5mm RED, GREEN, YELLOW (7 each)

Male Header = 2.54mm

12VDC 2A Power Adapter

Buy Components here: https://lcsc.com/

Step 3: Circuit Diagram and PCBs

To make this project, you also need a circuit diagram, which you can download from here for free!

Circuit Diagram for Control Board= http://www.mediafire.com/file/cb5wuk0c6j32qz4/Cont...

Circuit Diagram for Pole PCBs = http://www.mediafire.com/file/cssindrcxnda463/Pole...

After understanding Circuit diagram, of course, you will need a PCB. But don't worry, you will not need to design it. Here is a solution! Just go here: https://www.jlcpcb.com/, then upload free PCB Gerber files from the links given below. They are really professional PCB manufacturer and they have the cheapest prices that I have ever found ($2 for 10 pcs of 10 x10 cm boards). Download Free PCB Gerber Files here:

Control Board PCB = http://www.mediafire.com/file/ulvbxpoqp9xrqec/Gerb...

Pole PCB = http://www.mediafire.com/file/b04d918b6kyxbtp/Gerb...

Step 4: Soldering

After collecting all the materials, simply solder all the components to the printed circuit board according to the circuit diagram. It is very simple and easy because there are no special or complicated components used. Start with resistors, then solder LEDs in correct polarity and all other remaining components. and that's it!

Step 5: Arduino Code and Programming

After completing all circuit boards, upload arduino code to arduino nano. Code is very easy and simple. it is easy to understand even if you are a new programmer.

Download free code here:

LED_Traffic_Signals_Code.ino
Download

Step 6: Finalizing and Testing

After uploading code, attach arduino to control board in correct polarity. You can attach pole PCBs to the control board directly or using some extension male female connectors. there are 5 pins for connection on each pole PCB -,+, G,Y,R. Connect them respectively to the control board. Now connect a 12VDC 2A adapter to power jack and enjoy your Project!

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if you have any question about it, just write in comment section or simply text me on my Facebook page.