Traffic Light Controller

Tonight I made a lot of progress on the controller for the traffic lights. As mentioned in my previous post, I am going to use a simple ULN2003 to drive the LEDs. I chose this chip mostly because it was what I had on hand but also because it is very easy to use and requires no external components. Below is the circuit diagram.

The setup...

and the finished circuit board.

For the lights, I am using 12 volt LED tail lights that I got at Princess Auto for $2.99 each. I got one red light and two orange lights, thinking that it would be easy to put a green lighting gel in front of one of the orange lights to make it green. In the end, this idea did not work so, I had to make my own. I simply soldered 9 LEDs together and added a 100 ohm resistor to regulate the current. This worked great and was what I used in the final light.

The Final Controller in Action.

My green LED.