Introduction: USB Powered Traffic Light

About: Music: my profession for over 40 years... Electronics: my beloved hobby always.

This simple project is built on a single sided PC Board. All components are surface mounted except for the 3 LEDs. Of course, a microcontroller version would require many less parts but here you don´t need a programmer and all the components are economical and easy to find. I have it running all time on my office desktop connected to an USB port. Current drain is very low, an average of 25mA.

Step 1: PC Board

PC Board is single sided. Only drill holes for the LEDs. All other components are surface mounted.

Step 2: PC Board, Component Placement & Templates PDF

Click this Link for download

On this PDF you will find The PCB, placement guide and templates for the VISORS and back cover.

Print on glossy coated paper for the toner transfer. The visors are made directly with the print. For the back cover ant top triangle use light cardboard.

Step 3: LEDs & Lenses

LEDs are STRAW HAT lens type for a wide angle beam. External lenses are "bead surface" 60° lenses for good diffusion of the light.

Step 4: The Circuit Diagram

Step 5: Circuit Operation Details

Step 6: Remove the Thin Ends of IC Pins

This is for easier surface mounting.

Step 7: Assembly Steps

Step 8: Finished Views

Step 9: For More Details, Watch Video