Meadow.Foundation.Motors.ElectronicSpeedController

ElectronicSpeedController
Status
Source code	GitHub
Datasheet(s)	GitHub
NuGet package

float frequency = 50f;
const float armMs = 0.5f;
const float powerIncrement = 0.05f;

ElectronicSpeedController esc;
RotaryEncoderWithButton rotary;

public MeadowApp()
{
    Initialize();
    DisplayPowerOnLed(esc.Power);
}

void Initialize()
{
    Console.WriteLine("Initialize hardware...");

    //==== rotary encoder
    rotary = new RotaryEncoderWithButton(Device, Device.Pins.D07, Device.Pins.D08, Device.Pins.D06);
    rotary.Rotated += Rotary_Rotated;
    rotary.Clicked += (s, e) => {
        Console.WriteLine($"Arming the device.");
        _ = esc.Arm();
    }; ;

    //==== Electronic Speed Controller
    esc = new ElectronicSpeedController(Device, Device.Pins.D02, frequency);

    Console.WriteLine("Hardware initialized.");
}

private void Rotary_Rotated(object sender, Meadow.Peripherals.Sensors.Rotary.RotaryChangeResult e)
{
    esc.Power += (e.Direction == RotationDirection.Clockwise) ? powerIncrement : -powerIncrement;
    DisplayPowerOnLed(esc.Power);

    Console.WriteLine($"New Power: {esc.Power * (float)100:n0}%");
}

/// <summary>
/// Displays the ESC power on the onboard LED as full red @ `100%`,
/// blue @ `0%`, and a proportional mix, in between those speeds.
/// </summary>
/// <param name="power"></param>
void DisplayPowerOnLed(float power)
{
    // `0.0` - `1.0`
    int r = (int)Map(power, 0f, 1f, 0f, 255f);
    int b = (int)Map(power, 0f, 1f, 255f, 0f);

    var color = Color.FromRgb(r, 0, b);
}

float Map(float value, float fromSource, float toSource, float fromTarget, float toTarget)
{
    return (value - fromSource) / (toSource - fromSource) * (toTarget - fromTarget) + fromTarget;
}

Sample project(s) available on GitHub

|

Code Example

private readonly Frequency frequency = new Frequency(50, Frequency.UnitType.Hertz);
private const float armMs = 0.5f;
private const float powerIncrement = 0.05f;
private ElectronicSpeedController esc;
private RotaryEncoderWithButton rotary;

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

    rotary = new RotaryEncoderWithButton(Device.Pins.D07, Device.Pins.D08, Device.Pins.D06);
    rotary.Rotated += RotaryRotated;
    rotary.Clicked += (s, e) =>
    {
        Resolver.Log.Info($"Arming the device.");
        esc.Arm();
    }; ;

    esc = new ElectronicSpeedController(Device.Pins.D02, frequency);

    Resolver.Log.Info("Hardware initialized.");

    return base.Initialize();
}

private void RotaryRotated(object sender, RotaryChangeResult e)
{
    esc.Power += (e.New == RotationDirection.Clockwise) ? powerIncrement : -powerIncrement;
    DisplayPowerOnLed(esc.Power);

    Resolver.Log.Info($"New Power: {esc.Power * 100:n0}%");
}

/// <summary>
/// Displays the ESC power on the onboard LED as full red @ `100%`,
/// blue @ `0%`, and a proportional mix, in between those speeds.
/// </summary>
/// <param name="power"></param>
private void DisplayPowerOnLed(float power)
{
    // `0.0` - `1.0`
    int r = (int)ExtensionMethods.Map(power, 0f, 1f, 0f, 255f);
    int b = (int)ExtensionMethods.Map(power, 0f, 1f, 255f, 0f);

    var color = Color.FromRgb(r, 0, b);
}

public override Task Run()
{
    DisplayPowerOnLed(esc.Power);

    return base.Run();
}

Sample project(s) available on GitHub

Class ElectronicSpeedController

Driver for Electronic Speed Controllers (ESCs) typically used to control motors via PWM signals. To use, you generally have to calibrate the ESC through the following steps:

1. Depower the ESC, set the power to the intended maximum point (e.g., 1.0).
2. Power the ESC and wait for "happy tones" to indicate a good power supply, followed by possibly two beeps to indicate the max power limit set.
3. Set the ESC power to the intended minimum power point (e.g., 0.0), and the ESC should provide one beep for every LiPo cell (3.7V) of power supplied, followed by a long beep.
4. Optionally, for some ESCs, arm it by calling the Arm() method, which will drop the power below 0.0.

Assembly: ElectronicSpeedController.dll

View Source

Declaration

public class ElectronicSpeedController

Properties

ArmingPulseDuration

The pulse duration, in milliseconds, necessary to "arm" the ESC. Default value is 0.5ms.

View Source

Declaration

public float ArmingPulseDuration { get; set; }

Power

Gets or sets the power of the ESC, in the range of 0.0 to 1.0.

View Source

Declaration

public float Power { get; set; }

Frequency

Frequency (in Hz) of the PWM signal. The default is 50Hz. Increase for higher quality ESCs that allow higher frequency PWM control signals.

View Source

Declaration

public Frequency Frequency { get; }

IsDisposed

Gets a value indicating whether the object has been disposed.

View Source

Declaration

public bool IsDisposed { get; }

Methods

Arm()

Sends a 0.5ms pulse to the motor to enable throttle control.

View Source

Declaration

public void Arm()

CalculateDutyCycle(float, Frequency)

Calculates the appropriate duty cycle of a PWM signal for the given pulse duration and frequency.

View Source

Declaration

protected float CalculateDutyCycle(float pulseDuration, Frequency frequency)

Returns

System.Single: A duty cycle value expressed as a percentage between 0.0 and 1.0.

Parameters

Type	Name	Description
System.Single	pulseDuration	The duration of the target pulse in milliseconds.
Meadow.Units.Frequency	frequency	The frequency of the PWM signal.

CalculatePulseDuration(float)

Returns a pulse duration in milliseconds for the given power, assuming that the allowed power band is between 1ms and 2ms.

View Source

Declaration

protected float CalculatePulseDuration(float power)

Returns

System.Single: A pulse duration in milliseconds for the given power.

Parameters

Type	Name	Description
System.Single	power	A value between 0.0 and 1.0 representing the percentage of power, with 0.0 = 0% and 1.0 = 100%.

Dispose()

View Source

Declaration

public void Dispose()

Dispose(bool)

Dispose of the object

View Source

Declaration

protected virtual void Dispose(bool disposing)

Parameters

Type	Name	Description
System.Boolean	disposing	Is disposing