> For the complete documentation index, see [llms.txt](https://royals6234.gitbook.io/madmachine-examples/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://royals6234.gitbook.io/madmachine-examples/examples/makerkit/mission05buzzer.md).

# Mission 05 Buzzer

## What you need

## Circuit

## Tips

## Code

```swift
/*
  Mission5 Buzzer

  The buzz will play different tones when you rotate the potentiometer.

  The circuit:
  - Use Potentiometer Module or Light Sensor, and connect it to an Analog Jack.
  - Use Buzzer Module, and connect it to a Digital Jack.

  created 2019
  by Orange J

  Play a wonderful piece of music Happy Birthday!
  Numbered musical notation: 55 65 17 55 65 21 55 53 176 44 31 21.
  This example code is in the public domain.
  Visit madmachine.io for more info.
*/

import SwiftIO

let a0 = AnalogIn(Id.A0)

// PWM, also known as Pulse Width Modulation is a type of digital signal.
// The PWM signal can be used to configure a servo, or to control the dimming of a LED light.
// Initialize a PWM output pin.
let buzzer = PWMOut(Id.PWM2B)

while true {
    // Read the input voltage.
    value = a0.readPercent()

    //let value = a0.readPercent()
    let frequency = Int(1000 + 2000 * value) // calculate the float value into Int type to serve as frequency.
    buzzer.set(period: frequency, pulse: frequency/2) // Set PWM parameters.

    sleep(ms: 50) // Set the duration of the notes.
}
```

## Video

## See Also

## References

Last revision 2020/09/10 by Johnson