# 1.5 Doorbell

Today we will make a doorbell, click the bell sprite on the stage, the buzzer will sound; click again, the buzzer will stop sounding.

![](./img/1.5/1.5_bell_header.gif)

## Required Components

![](./img/1.5/1.5_list.png)

## Build the Circuit

![](./img/1.5/1.5_fritzing.png)

## Load the Code and See What Happens

Load the code file (`1.5_doorbell.sb3`) to Scratch 3.上

Click on the green flag on the stage. When we click on the Button 3 sprite, it will turn blue and then the buzzer will sound; when we click again, the **Button3** sprite reverts to gray and the buzzer stops sounding.

## Tips on Sprite

Delete the default sprite, then choose the **Bell** sprite.

![](./img/1.5/1.5_sprite.png)

Duplicate two bell characters

![](./img/1.5/1.5_sprite1.png)

Change the color of the bell2 sprite. Display the color when the doorbell is clicked

![](./img/1.5/1.5_sprite2.png)

Adjust the direction of the bell sprites for bell2 and bell3 sprite.

![](./img/1.5/1.5_sprite3.png)

## Tips on Codes

This block allows you to switch the sprite’s costume.

[![img](./img/1.5/1.5_code.png)](https://docs.sunfounder.com/projects/davinci-kit/en/latest/_images/1.13_buzzer4.png)


Set gpio17 to low to make the buzzer sound; set it to high and the buzzer will not sound.

[![img](./img/1.5/1.5_code1.png)](https://docs.sunfounder.com/projects/davinci-kit/en/latest/_images/1.13_buzzer5.png)


When the bell sprite is clicked, the program outputs a high-low voltage cycle with a period of 0.1 seconds to the GPIO pin. This drives a buzzer to produce a sound.

At the same time, the program alternates between showing the bell2 sprite and the bell3 sprite. This creates a visual effect that accompanies the buzzer sound.

![img](./img/1.5/1.5_code2.png)

In summary, the program creates a doorbell-like experience, where clicking the bell sprite triggers both an audible and visual response. The GPIO output controls a buzzer to make a ringing sound, while the costume changes of the bell sprite provide visual feedback to the user.

This Scratch program demonstrates the use of input/output control, timing, and sprite animation to create a simple but interactive electronics project. It's a great example of how Scratch can be used for basic hardware interfacing and multimedia projects.