MotorController

A C# stepper motor controller library for Raspberry Pi with GTK-based GUI. Controls stepper motors via GPIO pins with smooth acceleration/deceleration profiles using the David Austin algorithm.

Features

• Precise Motion Control: Smooth acceleration/deceleration using the David Austin stepper motor algorithm
• Thread-Safe Operations: Async/await pattern with proper cancellation support
• Limit Switch Support: Active-low limit switches with event-driven updates
• Cross-Platform Development: Mock GPIO controller for Windows development
• Touch-Friendly GUI: GTK 4.0-based interface designed for 800x480 touchscreen
• Configurable: Runtime configuration via JSON with GUI settings editor
• Well-Tested: Comprehensive unit tests using XUnit and NSubstitute

Target Platform

• Primary: Raspberry Pi (Linux ARM)
• Development: Windows/Linux with FakeGpioController simulation
• .NET Version: .NET 10.0

Prerequisites

• .NET SDK 10.0.102 or later
• For production: Raspberry Pi with GPIO-connected stepper motor driver
• For development: Windows or Linux (uses console-based GPIO simulation)

Quick Start

Build

# 1. Restore dependencies (required first step)
dotnet restore

# 2. Build the solution
dotnet build

# 3. Run tests
dotnet test

Configurable via GUI: All settings can be modified at runtime through the Settings dialog.

StepsPerRevolution Options

• 200, 400, 800, 1600, 3200, 6400, 12800

Default Pins (Raspberry Pi GPIO)

• Pulse: GPIO 21
• Direction: GPIO 20
• Min Limit Switch: GPIO 23 (active-low with pull-up)
• Max Limit Switch: GPIO 24 (active-low with pull-up)
• Enable: Optional (set to enable/disable motor driver)

Key Concepts

David Austin Algorithm

Implements smooth acceleration/deceleration:

• Initial delay: c0 = 0.676 * sqrt(2/α) * 10^6 microseconds
• Acceleration: cn = cn-1 - (2 * cn-1) / (4n + 1)
• Constant speed phase at target RPM
• Deceleration mirrors acceleration profile

Thread Safety

• Position tracking protected by SemaphoreSlim
• Async/await pattern throughout
• CancellationToken support for all motion methods

Microsecond-Precision Timing

• Custom MicrosecondSleep() using Stopwatch.GetTimestamp()
• No Thread.Sleep() (too imprecise for stepper pulses)

Usage Examples

Basic Motion Control

// Inject dependencies (via DI)
IStepperMotorController motor = serviceProvider.GetRequiredService<IStepperMotorController>();

// Move 5 inches at 100 RPM
await motor.MoveInchesAsync(5.0, 100.0, cancellationToken);

// Run to max limit switch at 50 RPM
await motor.RunToLimitSwitchAsync(toMaxLimit: true, 50.0, cancellationToken);

// Stop with deceleration
await motor.StopAsync();

// Reset position to zero
await motor.ResetPositionAsync();

// Get current position
double position = motor.CurrentPositionInches;

Limit Switch Events

motor.MinLimitSwitchTriggered += (sender, triggered) =>
{
    Console.WriteLine($"Min limit switch: {(triggered ? "TRIGGERED" : "Released")}");
};

motor.MaxLimitSwitchTriggered += (sender, triggered) =>
{
    Console.WriteLine($"Max limit switch: {(triggered ? "TRIGGERED" : "Released")}");
};

Testing

Run all tests:

dotnet test

Tests use NSubstitute to mock IGpioController interface, allowing full unit testing without hardware.

Dependencies

MotorController Library

• System.Device.Gpio v4.1.0
• Microsoft.Extensions.Logging v10.0.3

UI Application

• GirCore.Gtk-4.0 v0.7.0
• Microsoft.Extensions.Hosting v10.0.3
• Microsoft.Extensions.Logging.Console v10.0.3

Test Project

• xunit v2.9.3
• NSubstitute v5.3.0
• Microsoft.NET.Test.Sdk v18.0.1

Hardware Setup

1. Connect stepper motor driver to Raspberry Pi GPIO pins
2. Configure pins in UI/appsettings.json
3. Ensure limit switches are wired active-low with pull-ups
4. Optionally connect enable pin for motor driver control

Documentation

• Copilot Instructions: .github/copilot-instructions.md - Comprehensive development guide
• Project Specs:
  • MotorController/specs.md - Library requirements
  • UI/specs.md - GUI requirements
  • Test/specs.md - Testing requirements

Support

For issues, questions, or contributions, visit the GitHub repository: https://github.com/SuperTroye/MotorController