After the success of the first prototype, I began to wonder…in addition to a basic random choosing algorithm, what other functions do I need for this toy? For example, three buttons are not enough for this game’s multiplayer positioning, we need more buttons. But now that we have three, we can easily add a few more. Plus, what do we need when the correct button is pressed besides a buzzer？

First, we needed an electric device to drive the opening and closing of the crocodile’s jaw, so I thought of servo motor. The servo motor is a self-contained electrical device that is different from a regular motor because its output shaft can be adjusted to a variety of angles, positions and velocities. We can control the opening and closing of the crocodile’s jaw by controlling a servo motor’s angle through the code. The above is a sketch that shows my idea.

In addition to the servo motor, I wanted some visual reaction when the correct button was pressed. LED is a good option. I wanted a LED with different colors next to each button, so that each time the correct button was triggered, the corresponding LED would light up.

Here is the new prototype version with 4 buttons, 4 LEDs, a buzzer, and a servo motor. The code has been tested successfully. Each time the right button was triggered, the buzzer will buzz, the corresponding LED will light up, and the output shaft of the servo motor will rotate about 60 degrees and then reset after one second. Such a circuit basically meets the requirements of the circuitry perspective of this project.

Qinyuan Ashely Lu is a software engineer with an MS in Information Systems from Baruch College and an MS in Nonprofit Management from Columbia University. Ashely is an assistant instructor at the MakerHub where she can combine her love of coding, candy, and crocodiles.