Yeelight LAN protocol · .NET 10

A complete .NET client for Yeelight lights

Find Yeelight lights on your network, switch them, colour them and follow what they do, from any .NET application on Windows, Linux or macOS. Every command of the Yeelight LAN protocol is a typed, async C# member, a light's state follows the light whoever changes it, and the client stays within the limits of the lights (four connections, 60 commands a minute) by itself.

Get started API reference GitHub

dotnet add package YeelightClient --prerelease

using Yeelight;

await using var client = new YeelightClient();

var lights = await client.DiscoverAsync(TimeSpan.FromSeconds(4));

foreach (var light in lights)
{
    await light.TurnOnAsync();
    await light.SetBrightnessAsync(60, TimeSpan.FromSeconds(1));

    if (light.SupportsColor)
    {
        await light.SetRgbAsync(255, 140, 0);
    }
}

Why Yeelight Client

Finds lights on real networks

A search goes out as a multicast and as a broadcast, three times, from every network of the computer. Announcements are heard too, and one address can be asked directly, across a VPN or on another subnet.

The whole protocol, typed and async

Power, brightness, colour temperature, RGB, HSV, colour flows, scenes, timers, adjustments and background lights: a method for every command of the specification, with the arguments checked before anything is sent.

A state that follows the light

A light reports every change to its connections, so its properties are what it says, whoever changes it: the app, a remote, the wall switch. INotifyPropertyChanged and events tell you when.

Music mode for streaming effects

Put a light in music mode and send it commands without the limit of 60 a minute, to follow music or a screen. The client runs the server that the light connects to.

A connection you can rely on

One connection per light that is made again when it is lost, commands that fail at once instead of hanging, a limit of 60 commands a minute that the client keeps for you, and only one of the four connections that a light takes.

Tested against a simulated light

The tests run against a simulated light on the loopback, and add property-based tests, fuzzing of what a light could send, and a chaos test that cuts, stalls and refuses the connection at random while commands run.

A quick tour

using Yeelight;

await using var client = new YeelightClient();

// Search for four seconds ...
var lights = await client.DiscoverAsync(TimeSpan.FromSeconds(4));

// ... or ask one address, which also works across a VPN or on another subnet.
var light = await client.ProbeAsync("192.168.1.50");

await light.TurnOnAsync();
await light.SetBrightnessAsync(60, TimeSpan.FromSeconds(1));   // smooth, over one second
await light.SetColorTemperatureAsync(2700);
await light.SetRgbAsync(255, 140, 0);
await light.Background.SetRgbAsync(0, 128, 128);   // the second light of a ceiling light

client.DeviceDiscovered += (_, e) => Console.WriteLine($"Found {e.Device}");

client.DeviceStateChanged += (_, e) =>
    Console.WriteLine($"{e.Device.Name}: {e.PropertyName} (on: {e.Light.IsOn})");

client.StartDiscovery();   // a search now, and one every minute

var sunrise = new ColorFlow(
[
    ColorFlowStep.ColorTemperature(1700, TimeSpan.FromSeconds(1), brightness: 1),
    ColorFlowStep.ColorTemperature(2700, TimeSpan.FromMinutes(5), brightness: 60),
    ColorFlowStep.ColorTemperature(5000, TimeSpan.FromMinutes(5), brightness: 100),
],
count: 3,
action: ColorFlowAction.Stay);

await light.SetSceneAsync(YeelightScene.Flow(sunrise));   // the light runs it by itself

await using var music = await light.StartMusicModeAsync();

for (var hue = 0; hue < 360; hue += 6)
{
    await music.SetHsvAsync(hue, 100);   // no answer to wait for, and no limit of 60 a minute
    await Task.Delay(50);
}

Compatibility

Area	Support
Lights	Yeelight WiFi lights that follow the Yeelight WiFi Light Inter-Operation Specification, with LAN Control switched on in the Yeelight app (select the light, settings, LAN Control). What a light can do is what it lists: a mono light has no colours, and only some ceiling lights have a background light.
Target frameworks	`net10.0`, the current LTS release of .NET (supported until November 2028). An application on .NET 11 or a later version uses it too. Earlier versions of .NET are not supported.
Platforms	Windows, Linux and macOS: the client only uses sockets, and its tests run on all three in CI.
Dependencies	`Microsoft.Extensions.Logging.Abstractions` 10.0.0, which has the `ILogger` that the client logs to.
License	MIT
Affiliation	Yeelight Client is an independent open source project. It is not affiliated with or endorsed by Yeelight.

A complete .NET client for Yeelight lights

Why Yeelight Client

Finds lights on real networks

The whole protocol, typed and async

A state that follows the light

Music mode for streaming effects

A connection you can rely on

Tested against a simulated light

A quick tour

Compatibility

Where next

Getting started

Finding lights

The test app

API reference