Buzzer.cs

// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.

using System;
using System.Device.Model;
using System.Device.Pwm;
using System.Threading;

namespace Iot.Device.Buzzer
{
    /// <summary>
    /// Simple buzzer.
    /// </summary>
    [Interface("Simple buzzer")]
    public class Buzzer : IDisposable
    {
        private PwmChannel _pwmChannel;

        /// <summary>
        /// Initializes a new instance of the <see cref="Buzzer" /> class.
        /// </summary>
        /// <param name="pinNumber">Pin connected to buzzer.</param>
        public Buzzer(int pinNumber)
            : this(PwmChannel.CreateFromPin(pinNumber))
        {
        }

        /// <summary>
        /// Initializes a new instance of the <see cref="Buzzer" /> class.
        /// </summary>
        /// <param name="chip">The GPIO pin number in case of a software PWM. The chip in case of a hardware PWM.</param>
        /// <param name="channel">The channel to use in case of a hardware PWM.</param>
        public Buzzer(int chip, int channel)
            : this(PwmChannel.Create(chip, channel))
        {
        }

        /// <summary>
        /// Initializes a new instance of the <see cref="Buzzer" /> class.
        /// </summary>
        /// <param name="pwmChannel">The PWM controller to use during work.</param>
        public Buzzer(PwmChannel pwmChannel) => _pwmChannel = pwmChannel;

        /// <summary>
        /// Set new or overwrite previously set frequency and start playing the sound.
        /// </summary>
        /// <param name="frequency">Tone frequency in Hertz.</param>
        [Command]
        public void StartPlaying(double frequency)
        {
            _pwmChannel.Frequency = (int)frequency;
            _pwmChannel.Start();
        }

        /// <summary>
        /// Stop playing tone.
        /// </summary>
        [Command]
        public void StopPlaying() => _pwmChannel.Stop();

        /// <summary>
        /// Play tone of specific frequency for specified duration.
        /// </summary>
        /// <param name="frequency">Tone frequency in Hertz.</param>
        /// <param name="duration">Playing duration in millisecons.</param>
        [Command]
        public void PlayTone(double frequency, int duration)
        {
            StartPlaying(frequency);
            Thread.Sleep(duration);
            StopPlaying();
        }

        /// <summary>
        /// Dispose Buzzer.
        /// </summary>
        public void Dispose()
        {
            _pwmChannel?.Dispose();
            _pwmChannel = null;
        }
    }
}