RevolutionPi

This package provides a comprehensive abstraction for interacting with Revolution Pi hardware (and virtualized devices) within a PHP application. It enables process image access, IO control, LED control, serial port management, and more, with a convenient and flexible API.

The package has specific support for Laravel, and Laravel Zero. It can also be used with plain PHP, although some functionality such as the auto-generation commands will not be available.

The package works with the built-in PHP 8.2 on the Debian Bookworm image shipped in the RevolutionPi. No extra extensions or configuration changes are required.

Features

• ProcessImage: Full read/write access to PiControl variables.
• Trait-based interface: Add Revolution Pi capabilities to your own app classes via the RevolutionPi trait.
• LED support: Control and read RevPi device LEDs (color, position).
• Serial communications: Robust non-blocking serial port abstraction for baud rate, parity, stop/data bits, flags
• Monitor/Observer: Register IO monitor callbacks for change detection.
• Magic method & attribute support: Easy, expressive access to IO variables, matching your PiCtory configuration.
• Remote (WebSocket/RPC) and Virtual device support.

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Table of Contents

• Installation
• Simplified interface
  • Accessing IO variables
  • Monitoring IO variables
  • Process image
  • LED control
  • Serial port access
• Remote interface
• Low-level interface
  • Hardware devices (PiControl, Terminal)
  • ProcessImage interface
  • SerialPort interface
  • Monitoring with custom monitors
• Deployment
• Example: Polling and running the event loop
• CLI Commands
• License

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Installation

Require with Composer

composer require flat3/revpi

Out of the box revpi pulls in only the required packages.

To include the PHP class generator

composer require --dev nette/php-generator

To include websocket support

composer require amphp/websocket-server amphp/websocket-client

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Quick start

flat3/revpi makes heavy use of the Laravel service container. All concrete implementations can be resolved from interfaces. Code should either be run on the RevolutionPi device, or via an IDE that can run code remotely like PhpStorm.

Note that Laravel Zero does not use package auto-discovery. You will need to add this package's service provider to your config/app.php.

  use Flat3\RevPi\Interfaces\Module;
  use Flat3\RevPi\Led\LedColour;
  use Flat3\RevPi\Led\LedPosition;
  
  $pi = app(Module::class); // Resolved from the interface to the correct module type

  $pi->led(LedPosition::A1)->set(LedColour::Red);
  print_r($pi->led(LedPosition::A1)->get());

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Simplified Interface

It's recommended to generate a device-specific class from your exported PiCtory JSON. This provides IDE auto-completion for all IO variables as strongly typed methods and documented properties.

1. Export your configuration from the PiCtory web interface as a project file
   (e.g. pictory.rsc)

2. Generate the PHP class

  php artisan revpi:generate pictory.rsc MyPi

This creates app/MyPi.php.

3. Use your class

  use Flat3\RevPi\Interfaces\Module;
  use Flat3\RevPi\Interfaces\SerialPort;
  use Flat3\RevPi\Led\LedColour;
  use Flat3\RevPi\Led\LedPosition;
  use Flat3\RevPi\Monitors\DigitalMonitor;
  use Flat3\RevPi\SerialPort\BaudRate;
  use Flat3\RevPi\SerialPort\LocalFlag;
  use Illuminate\Console\Command;
  use Revolt\EventLoop;

  $pi = new \App\MyPi;
   
  // Create an instance of the serial port that loops the input back to the output
  $port = $pi->serialPort();
  $port->setSpeed(BaudRate::B576000);
  $port->clearFlag(LocalFlag::CanonicalInput);
  $port->onReadable(function (SerialPort $port) {
      $port->write($port->read(1024));
  });

  // Monitor the core temperature, writing updated values to the serial port
  $pi->Core_Temperature()->monitor(new DigitalMonitor, function ($value) use ($port) {
      $port->write($value."\n");
  });

  // Start polling
  $pi->module()->resume();

  // Start the event loop
  EventLoop::run();

Accessing IO Variables

Assuming your PiCtory-exported class has an input named input1 and an output named output1:

$pi = new \App\MyPi;

// Read input (as property)
$level = $pi->input1; // int|bool

// Or as a method (returns InputIO object)
$input = $pi->input1();
$currentValue = $input->get();

// Read output
$currentStatus = $pi->output1;

// Set output (as property)
$pi->output1 = true;

// Or as a method (returns OutputIO object)
$pi->output1()->set(1);

// Reset output to its default value
$pi->output1()->reset();

Monitoring IO Variables

The monitor will cause the callback to be called whenever the monitored value changes.

use Flat3\RevPi\Monitors\DigitalMonitor;

$pi = new \App\MyPi;

$pi->input1()->monitor(new DigitalMonitor, function($newValue) {
    // React to input1 changes
    logger("input1 changed: $newValue");
});

Monitor::debounce

Configures the monitor to fire only after changes stop for the given interval (in milliseconds).

$pi->input1()->monitor((new DigitalMonitor)->debounce(200), function($value) {
    // Handle change after quiet period
});

Monitor::throttle

Configures the monitor to fire at most once per interval (in milliseconds).

$pi->input1()->monitor((new DigitalMonitor)->throttle(200), function($value) {
    // Handle change no more than every 200ms
});

Process Image (Low-Level)

Get the raw process image interface for advanced access:

$image = $pi->processImage();

$value = $image->readVariable('input1');
$image->writeVariable('output1', 1);
$dump = $image->dumpImage(); // Raw string of process image data
$info = $image->getDeviceInfo(); // Information about the base module
$infoList = $image->getDeviceInfoList(); // Information about all expansion modules

LED Control

use Flat3\RevPi\Led\LedColour;
use Flat3\RevPi\Led\LedPosition;

// Set LED A1 to green
$pi->led(LedPosition::A1)->set(LedColour::Green);

// Get current LED color (as enum)
$current = $pi->led(LedPosition::A1)->get(); // LedColour instance

// Turn an LED off
$pi->led(LedPosition::A1)->off();

Serial Port Access

use Flat3\RevPi\SerialPort\BaudRate;

// Open default serial port
$port = $pi->serialPort();

// Or specify device path:
$port = $pi->serialPort('/dev/ttyRS485-1');

// Configure the port:
$port->setSpeed(BaudRate::B9600);
$port->setParity(Parity::Even);
$port->setDataBits(DataBits::CS8);

// Write and read
$port->write("Hello, RevPi!");
$response = $port->read(128); // up to 128 bytes

// Register event handler for readable data
$port->onReadable(function (SerialPort $port) {
    echo "Serial received: " . $port->read(1024) . "\n";
});

// Flush or break
$port->flush(QueueSelector::Both);
$port->break();

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Remote interface

You can communicate with a remote RevPi device via a WebSocket by calling the remote method on the client before using the module.

use Flat3\RevPi\RevolutionPi;

$pi = new \App\MyPi;

// Adding the remote call creates a connection to a device
$pi->remote('ws://10.1.2.3:12873'); 

// From now, other methods act remotely:
$pi->output1 = 1;
$status = $pi->input2;
$pi->led(LedPosition::A1)->set(LedColour::Cyan);

The remote device should listen for incoming connections, use php artisan revpi:listen to start the server on the device.

Remote devices support the same features that local devices do, including reading and writing to the process image, using the serial ports and setting up change monitors.

Out of the box the package does not provide for authentication or encryption. These can be added by creating a more complex websocket handshake object and passing it to the remote method. On the server-side, the basic revpi:listen code can be modified to support encryption and authentication.

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Low-level interface

Hardware Devices (PiControl, Terminal)

You can inject or instantiate the underlying devices (see Flat3\RevPi\Interfaces\Hardware\*) for advanced operations, e.g. binary FFI device IO, custom IOCTLs, etc.

$picontrol = app(\Flat3\RevPi\Interfaces\Hardware\PiControl::class);
$terminal = app(\Flat3\RevPi\Interfaces\Hardware\Terminal::class);

ProcessImage Interface

Everything required for direct process image manipulation:

$image = app(\Flat3\RevPi\Interfaces\ProcessImage::class);

$value = $image->readVariable('SomeName');
$image->writeVariable('OtherVar', 123);

SerialPort Interface

Inject or use via the module interface.

$port = app(\Flat3\RevPi\Interfaces\SerialPort::class); // Usually you want $pi->serialPort(...)

Monitoring with Custom Monitors

If you want to create a custom monitor:

use Flat3\RevPi\Monitors\Monitor;

class MyMonitor extends Monitor {
    public function evaluate(int|bool $next): bool {
        // Implement custom transition/action logic here
        // e.g. if crossing a threshold
        // Return true if the monitor has detected sufficient change
    }
}

// Register:
$pi->module()->monitor('input1', new MyMonitor, function($newValue) {
    // Callback logic
});

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Deployment

The package has been specifically designed to work with Laravel Zero. Using the standalone application feature will convert your RevolutionPi project into a single executable file that can be started automatically when the base module boots up.

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Example: Polling and running the event loop

Typically you'll want to run your polling/event loop. The package provides an artisan command (see below) or call from code:

use Revolt\EventLoop;

$pi = new \App\MyPi;

$pi->repeat(1, function($pi) {
    // This is called every second
    logger("Current value is: " . $pi->input1);
});

EventLoop::run();

Or as a CLI command:

php artisan revpi:run

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CLI Commands

This package includes artisan commands (php artisan revpi):

• revpi:generate <pictory.json> [class]
  Generate a typed PHP class for your device from your pictory export.

• revpi:run
  Run your polling/event loop (call resume() and enter main loop).

• revpi:led:get <position>
  Display current color of the chosen LED.

• revpi:led:set <position> <colour>
  Set a given LED (positions: a1–a5; colors: off, red, green, orange, blue, magenta, cyan, white).

• revpi:info
  List available device(s) and their info/status.

• revpi:dump <file>
  Dump the current process image binary to a file.

• revpi:listen [--address=0.0.0.0] [--port=12873]
  Run the JSON-RPC/WS server for remote connections.

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License

MIT
Flat3/RevPi, 2025.

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Further Reading

• Revolution Pi Documentation
• PiCtory Configuration Tool
• Laravel Documentation
• Amp
• FFI Manual (PHP)

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