This project utilizes an ArduinoUno and follows the idea of allowing students to use such tools to create and build their own projects; my partner, Xandrew Julian, and I built a stoplight that had the capabilities to emit buzz sounds from a buzzer. The tones and patterns that you would hear would depend on the color of stoplight and the transition to the next one. In addition, a pedestrian button was implemented to start transitioning the light from green to red so he could cross safely. At the beginning the light is green. It will stay green until the pedestrian button is pressed. When it turns yellow, a buzz sound is made. When it turns red, a different buzzer sound is heard. After the signal goes to red, the stoplight would transition back to green again and make another different buzzer sound. Afterwards the whole cycle will repeat again.
You can learn more at the Computer Engineering EE 296 Embedded System Design website.