Irrigation System Control via Mobile App

Implementing Irrigation System Control via Mobile Applications

Field irrigation controllers — devices with relays that open and close electromagnetic solenoid valves on zones. Rain Bird, Hunter, Orbit — the most known names. Most communicate with "smart" hubs via proprietary protocols. For custom integration into mobile applications, use either manufacturer APIs (if available), replace the controller with IoT-compatible hardware (ESP32 with MQTT, Raspberry Pi with GPIO), or an intermediate gateway.

Rachio API: Cloud Integration

Rachio is one of the few manufacturers with public REST API. OAuth 2.0 authentication, full_control scope:

// iOS, async/await
class RachioClient {
    let baseURL = "https://api.rach.io/1/public"
    var accessToken: String

    func getPersonInfo() async throws -> PersonInfo {
        return try await get("/person/info")
    }

    func startZone(zoneId: String, duration: Int) async throws {
        // duration in seconds
        try await put("/zone/start", body: [
            "id": zoneId,
            "duration": duration
        ])
    }

    func stopDevice(deviceId: String) async throws {
        try await put("/device/stop_water", body: ["id": deviceId])
    }

    func createScheduleRule(deviceId: String, zones: [ZoneSchedule]) async throws -> ScheduleRule {
        return try await post("/schedulerule", body: [
            "device": ["id": deviceId],
            "name": zones.first?.name ?? "Schedule",
            "zones": zones.map { ["id": $0.id, "duration": $0.durationSeconds] },
            "startTime": 21600, // seconds from midnight = 6:00
            "type": "FIXED_SCHEDULE"
        ])
    }
}

Rachio Webhook allows receiving real-time events: watering start/stop, valve errors, rain detection. Register webhook via API; events arrive as POST requests to developer server, which forwards them to mobile app via WebSocket or FCM.

MQTT Controller: Custom Hardware

For custom installations — ESP32 controller with MQTT. Topics:

irrigation/zone/1/command   → {"action": "open", "duration": 300}
irrigation/zone/1/state     → {"isOpen": true, "openedAt": "2024-07-15T06:00:00Z"}
irrigation/system/status    → {"activeZones": [1,3], "waterFlow": 12.5, "pressure": 2.8}

Mobile app subscribes to irrigation/+/state and irrigation/system/status. Control — publish to irrigation/zone/+/command.

For Flutter:

class IrrigationRepository {
  late MqttServerClient _client;
  final StreamController<ZoneState> _zoneStateController = StreamController.broadcast();

  Stream<ZoneState> get zoneStates => _zoneStateController.stream;

  Future<void> connect(MqttConfig config) async {
    _client = MqttServerClient(config.host, config.clientId)
      ..port = config.port
      ..secure = true
      ..securityContext = config.sslContext
      ..keepAlivePeriod = 30
      ..onDisconnected = _onDisconnected;

    await _client.connect(config.username, config.password);
    _client.subscribe('irrigation/+/state', MqttQos.atLeastOnce);

    _client.updates!.listen((messages) {
      for (final message in messages) {
        final payload = MqttPublishPayload.bytesToStringAsString(
          (message.payload as MqttPublishMessage).payload.message,
        );
        final zoneId = _extractZoneId(message.topic);
        _zoneStateController.add(ZoneState.fromJson(zoneId, jsonDecode(payload)));
      }
    });
  }

  Future<void> startZone(int zoneId, Duration duration) async {
    final builder = MqttClientPayloadBuilder();
    builder.addString(jsonEncode({
      'action': 'open',
      'duration': duration.inSeconds,
    }));
    _client.publishMessage(
      'irrigation/zone/$zoneId/command',
      MqttQos.atLeastOnce,
      builder.payload!,
    );
  }
}

Schedule and Automation

Irrigation schedule is a separate screen where you set zones, duration, and repetition. Complexity: schedule must account for weather forecast (skip watering if rain expected) and soil sensor data.

Integrate with weather forecast via Open-Meteo API (free, no key):

Future<bool> shouldSkipIrrigation(double lat, double lon) async {
  final url = Uri.parse(
    'https://api.open-meteo.com/v1/forecast'
    '?latitude=$lat&longitude=$lon'
    '&daily=precipitation_sum'
    '&forecast_days=2'
    '&timezone=auto'
  );
  final response = await http.get(url);
  final data = jsonDecode(response.body);
  final todayRain = data['daily']['precipitation_sum'][0] as double;
  final tomorrowRain = data['daily']['precipitation_sum'][1] as double;
  // Skip if today or tomorrow has >5mm rain
  return todayRain > 5.0 || tomorrowRain > 5.0;
}

Zone Management UX

Zone management screen — map or schematic plan with color indicators: green — active zone, gray — inactive, red — valve error. Long tap on zone — start manual watering with time selection (slider 1-60 minutes).

"Stop all" button must always be accessible in one action — don't hide in menu.

Developing irrigation control application with Rachio API or custom MQTT controller, schedule and weather integration: 3-5 weeks. Cost calculated after clarifying equipment and zone count.