Control Powered Up motors and lights from an @Observable Swift interface

PFunc talks to LEGO® Powered Up hubs over Bluetooth Low Energy (BLE). Core Bluetooth does the heavy lifting, managing connections and writing instructions to the hubs.

PFunc implements just enough of the LEGO Wireless Protocol to replace the 88010 Remote Control and drive the current generation of Powered Up attachments from the 2- and 4-port consumer hubs.

88012 Hub	88009 Hub

88011 Train Motor	88013 Large Motor

45303 Motor	88005 Light

Written in Swift 6.2 for Apple stuff:

• macOS 15 Sequoia
• iOS/iPadOS 18
• visionOS 2

Build with Xcode 26 or newer.

Apps using PFunc are using Core Bluetooth. Your app will crash if its Info.plist doesn't include NSBluetoothAlwaysUsageDescription privacy description.

Additionally, app entitlements need to enable Bluetooth:

macOS	iOS, visionOS

Add p-func package to your Xcode project, then add PFunc library to the app target(s).

Add @Observable PFunc object to the SwiftUI app environment; connect nearby hubs when Bluetooth is enabled:

import SwiftUI
import PFunc

@main
struct App: SwiftUI.App {
    @State private var pFunc: PFunc = PFunc()
    
    // MARK: App
    var body: some Scene {
        WindowGroup {
            ContentView()
                .environment(pFunc)
                .onChange(of: pFunc.state) {
                    if pFunc.state == .poweredOn {
                        pFunc.connect()
                    }
                }
        }
    }
}

All hub property updates are published:

• Advertising name (14-character ASCII string)
• Battery voltage (0-100%)
• Bluetooth signal strength (poor/fair/good w/ relative dbm) and connection status (CBPeripheralState)
• Built-in RGB light color (10 named presets or custom RGB 0-255)
• Ports and attached devices (automatically detect/init known Device types)

Detect when a device is attached to a port and operate functions:

import PFunc
import SwiftUI

struct RemoteControl: View {
    init(hub id: UUID) {
        self.id = id
    }
    
    @Environment(PFunc.self) private var pFunc: PFunc
    private let id: UUID
    
    private var device: Device? { pFunc.hub(id)?.device(at: .external(.a)) }
    
    // MARK: View
    var body: some View {
        Button(action: {
            if let light: LEDLight = device as? LEDLight {
                light.intensity = light.intensity == .off ? .percent(50) : .off
            } else if let motor: Motor = device as? Motor {
                motor.power = motor.power == .float ? .forward(50) : .float)
            }
        }) {
            Text("Toggle Device Function")
        }
        .disabled(device == nil)
    }
}

Both advertising name and RGB light color are settable and resettable:

pFunc.hub(id)?.resetName("New Hub Name")
pFunc.hub(id)?.resetName() // Reset name back to firmware default

pFunc.hub(id)?.rgbLightColor = .red

Name changes are persisted on the hub across connections, until changed or reset. RGB light color always starts at hub default on connection. (To remember which hubs were which color last time connected, your app can depend on the Core Bluetooth peripheral CBUUID being the same across connections.)

I had a little help from the Internet:

• Notes on LEGO wireless BLE protocol
• Powered UP - Community Docs (the missing device docs ...)
• SmartBotKit LWP

PFunc is not affiliated with the LEGO Group. LEGO® is a trademark of the LEGO Group, which does not sponsor, authorize or endorse this software.