Add this audio sensor to your autonomous robot to allow it to play a game. Your robot may already have IR, ultrasonic, or audio sensors to navigate or follow a signal. Here is a fun little circuit you can add to a robot, and have it play Marco Polo. It senses a whistle and responds with a buzzer sound of it’s own. If your robot also tracks the direction of the whistling sound, you can have the robot run away (or towards the sound). You could also use this with a whistle or clap controlled device to have a confirmation that the signal was received.
This circuit amplifies and filters the input form the microphone so that only the whistling sound activates the response. The CD4049UB has 6 inverters in it, and all 6 are used in this circuit for amplification, filtering, and as a vibrator to generate the response tone.