Meadow.Foundation.Leds.PwmLedBarGraph

PwmLedBarGraph
Status
Source code	GitHub
NuGet package

An LED Bar Graph is packaged array of LEDs commonly used to indicate level or progress and commonly include 8 or 10 leds.

The PwmLedBarGraph class allows you to control an led bar graph using PWM ports.

Use the SetLed method to turn on or off LEDs individually, or assign a value on the Percentage property to represent it visually on the graph bar, like a battery indicator, temperature, humidity, etc.

Code Example

PwmLedBarGraph pwmLedBarGraph;

public override Task Initialize()
{
    Resolver.Log.Info("Initializing...");

    // Using an array of Pins that support PWM (F7v2: D02-D04, D07-D13)
    IPin[] pins =
    {
        Device.Pins.D11,
        Device.Pins.D10,
        Device.Pins.D09,
        Device.Pins.D08,
        Device.Pins.D07,
        // Device.Pins.D06, // Only available for PWM on F7v1
        // Device.Pins.D05, // Only available for PWM on F7v1
        Device.Pins.D04,
        Device.Pins.D03,
        Device.Pins.D02
    };

    pwmLedBarGraph = new PwmLedBarGraph(pins, new Voltage(2.2));

    return Task.CompletedTask;
}

public override async Task Run()
{
    Resolver.Log.Info("TestLedBarGraph...");

    float percentage = 0;

    while (true)
    {
        Resolver.Log.Info("Turning them on and off for 200ms using SetLed...");
        for (int i = 0; i < pwmLedBarGraph.Count; i++)
        {
            await pwmLedBarGraph.SetLed(i, true);
            await Task.Delay(100);
            await pwmLedBarGraph.SetLed(i, false);
        }

        await Task.Delay(1000);

        Resolver.Log.Info("Turning them on using Percentage...");
        while (percentage < 1)
        {
            percentage += 0.01f;
            await pwmLedBarGraph.SetPercentage(Math.Min(1.0f, percentage));
            await Task.Delay(100);
        }

        await Task.Delay(1000);

        Resolver.Log.Info("Turning them off using Percentage...");
        while (percentage > 0)
        {
            percentage -= 0.01f;
            await pwmLedBarGraph.SetPercentage(Math.Max(0.0f, percentage));
            await Task.Delay(100);
        }

        await Task.Delay(1000);

        Resolver.Log.Info("Blinking for 5 seconds at 500ms on/off...");
        await pwmLedBarGraph.StartBlink();
        await Task.Delay(5000);
        await pwmLedBarGraph.StopAnimation();

        await Task.Delay(1000);

        Resolver.Log.Info("Bar blinking with high and low brightness for 5 seconds...");
        await pwmLedBarGraph.StartBlink(TimeSpan.FromMilliseconds(200), TimeSpan.FromMilliseconds(200), 0.75f, 0.25f);
        await Task.Delay(5000);
        await pwmLedBarGraph.StopAnimation();

        await Task.Delay(1000);

        Resolver.Log.Info("Bar pulsing for 5 seconds...");
        await pwmLedBarGraph.StartPulse();
        await Task.Delay(5000);
        await pwmLedBarGraph.StopAnimation();

        await Task.Delay(1000);

        await pwmLedBarGraph.SetBrightness(0);

        await Task.Delay(1000);
    }
}

Sample project(s) available on GitHub

Wiring Example

Class PwmLedBarGraph

Represents an LED bar graph composed on multiple PWM LEDs

Assembly: Meadow.Foundation.dll

View Source

Declaration

public class PwmLedBarGraph

Properties

Count

The number of the LEDs in the bar graph

View Source

Declaration

public int Count { get; }

Percentage

A value between 0 and 1 that controls the number of LEDs that are activated

View Source

Declaration

public float Percentage { get; protected set; }

Fields

pwmLeds

Array to hold pwm leds for bar graph

View Source

Declaration

protected PwmLed[] pwmLeds

Methods

StopAnimation()

Stops the LED bar graph when its blinking

View Source

Declaration

public Task StopAnimation()

Returns

System.Threading.Tasks.Task

StopAnimation(int)

Stops the blinking animation on an individual LED

View Source

Declaration

public Task StopAnimation(int index)

Returns

System.Threading.Tasks.Task

Parameters

Type	Name	Description
System.Int32	index	Index of the LED

StartBlink(int, float, float)

Starts a blink animation on an individual LED

View Source

Declaration

public Task StartBlink(int index, float highBrightness = 1, float lowBrightness = 0)

Returns

System.Threading.Tasks.Task

Parameters

Type	Name	Description
System.Int32	index	Index of the LED
System.Single	highBrightness	The maximum brightness of the animation
System.Single	lowBrightness	The minimum brightness of the animation

StartBlink(int, TimeSpan, TimeSpan, float, float)

Starts a blink animation on an individual LED

View Source

Declaration

public Task StartBlink(int index, TimeSpan highBrightnessDuration, TimeSpan lowBrightnessDuration, float highBrightness = 1, float lowBrightness = 0)

Returns

System.Threading.Tasks.Task

Parameters

Type	Name	Description
System.Int32	index	Index of the LED
System.TimeSpan	highBrightnessDuration	The duration the LED stays in high brightness
System.TimeSpan	lowBrightnessDuration	The duration the LED stays in low brightness
System.Single	highBrightness	The maximum brightness of the animation
System.Single	lowBrightness	The minimum brightness of the animation

StartBlink(float, float)

Start the Blink animation which sets the brightness of the LED alternating between a low and high brightness setting.

View Source

Declaration

public Task StartBlink(float highBrightness = 1, float lowBrightness = 0)

Returns

System.Threading.Tasks.Task

Parameters

Type	Name	Description
System.Single	highBrightness	The maximum brightness of the animation
System.Single	lowBrightness	The minimum brightness of the animation

StartBlink(TimeSpan, TimeSpan, float, float)

Start the Blink animation which sets the brightness of the LED alternating between a low and high brightness setting, using the durations provided.

View Source

Declaration

public Task StartBlink(TimeSpan highBrightnessDuration, TimeSpan lowBrightnessDuration, float highBrightness = 1, float lowBrightness = 0)

Returns

System.Threading.Tasks.Task

Parameters

Type	Name	Description
System.TimeSpan	highBrightnessDuration	On duration.
System.TimeSpan	lowBrightnessDuration	Off duration.
System.Single	highBrightness	High brightness.
System.Single	lowBrightness	Low brightness.

StartPulse(int, float, float)

Starts a pulse animation on an individual LED

View Source

Declaration

public Task StartPulse(int index, float highBrightness = 1, float lowBrightness = 0.15)

Returns

System.Threading.Tasks.Task

Parameters

Type	Name	Description
System.Int32	index	Index of the LED
System.Single	highBrightness	The maximum brightness of the animation
System.Single	lowBrightness	The minimum brightness of the animation

StartPulse(int, TimeSpan, float, float)

Starts a pulse animation on an individual LED with the specified pulse cycle

View Source

Declaration

public Task StartPulse(int index, TimeSpan pulseDuration, float highBrightness = 1, float lowBrightness = 0.15)

Returns

System.Threading.Tasks.Task

Parameters

Type	Name	Description
System.Int32	index	Index of the LED
System.TimeSpan	pulseDuration	The pulse animation duration
System.Single	highBrightness	The maximum brightness of the animation
System.Single	lowBrightness	The minimum brightness of the animation

StartPulse(float, float)

Start the Pulse animation which gradually alternates the brightness of the LED between a low and high brightness setting.

View Source

Declaration

public Task StartPulse(float highBrightness = 1, float lowBrightness = 0.15)

Returns

System.Threading.Tasks.Task

Parameters

Type	Name	Description
System.Single	highBrightness	The maximum brightness of the animation
System.Single	lowBrightness	The minimum brightness of the animation

StartPulse(TimeSpan, float, float)

Start the Pulse animation which gradually alternates the brightness of the LED between a low and high brightness setting, using the durations provided.

View Source

Declaration

public Task StartPulse(TimeSpan pulseDuration, float highBrightness = 1, float lowBrightness = 0.15)

Returns

System.Threading.Tasks.Task

Parameters

Type	Name	Description
System.TimeSpan	pulseDuration	The pulse animation duration
System.Single	highBrightness	The maximum brightness of the animation
System.Single	lowBrightness	The minimum brightness of the animation

ValidateBrightness(float, float)

Validates LED brightness to ensure they're within the range 0 (off) - 1 (full brightness)

View Source

Declaration

protected void ValidateBrightness(float highBrightness, float lowBrightness)

Parameters

Type	Name	Description
System.Single	highBrightness	The maximum brightness of the animation
System.Single	lowBrightness	The minimum brightness of the animation

GetTopLedForPercentage()

Returns the index of the last LED turned on

View Source

Declaration

public int GetTopLedForPercentage()

Returns

System.Int32

SetLed(int, bool)

Set the LED state

View Source

Declaration

public Task SetLed(int index, bool isOn)

Returns

System.Threading.Tasks.Task

Parameters

Type	Name	Description
System.Int32	index	Index of the LED
System.Boolean	isOn	True for on, False for off

SetLedBrightness(int, float)

Set the brightness of an individual LED when using PWM

View Source

Declaration

public Task SetLedBrightness(int index, float brightness)

Returns

System.Threading.Tasks.Task

Parameters

Type	Name	Description
System.Int32	index	Index of the LED
System.Single	brightness	Valid values are from 0 to 1, inclusive

SetPercentage(float)

Set the percentage of LEDs that are on starting from index 0

View Source

Declaration

public Task SetPercentage(float percentage)

Returns

System.Threading.Tasks.Task

Parameters

Type	Name	Description
System.Single	percentage	Percentage (Range from 0 - 1)

SetBrightness(float)

Set the brightness to the LED bar graph using PWM

View Source

Declaration

public Task SetBrightness(float brightness)

Returns

System.Threading.Tasks.Task

Parameters

Type	Name	Description
System.Single	brightness	Valid values are from 0 to 1, inclusive