This is an old revision of the document!
The Pi-Traffic light provides a fun and easy way to add three 10mm LEDs to your Raspberry Pi project. The red, yellow and green LEDs give visual feedback to the Raspberry Pi GPIO. The Pi-Traffic light can also be used as a tool to learn about controlling the Raspberry Pi GPIO pins.
Product information: http://lowvoltagelabs.com/products/pi-traffic/
* Schematic in PDF format http://lowvoltagelabs.com/wp-content/uploads/2014/08/pi-traffic_schematic_rev1405.pdf
On the Raspberry Pi Model A and B the Pi Traffic light connects to GPIO pins 9,10 and 11. When looking at the front of the Raspberry Pi these pins are located at the back left corner of the Raspberry Pi GPIO header. The Pi Traffic light installs vertically on the four back left pins of the GPIO header. See the photo below.
Pi Traffic Light installed