Chirpstack JS decoder for Radiobridge devices

radiobridge.js

// Decode decodes an array of bytes into an object.
//  - fPort contains the LoRaWAN fPort number
//  - bytes is an array of bytes, e.g. [225, 230, 255, 0]
// The function must return an object, e.g. {"temperature": 22.5}
/*
@reference https://radiobridge.com/documents/Common%20Sensor%20Messages.pdf

Sensors Name                            Designation
------------------------------------------------------------
Water Sensor                            RBS301-WAT-US
Water Rope Sensor                       RBS301-WR1M-US
External Probe Temperature Sensor       RBS301-TEMP-EXT-US
Ultrasonic Level Sensor                 RBS306-US10M-US
Air Temperature and Humidity Sensor     RBS306-ATH-EXT-US
Tilt Sensor                             RBS301-TILT-US
Acceleration-based Movement Sensor      RBS301-ABM-US
*/
function Decode(fPort, bytes, variables) {
  switch (bytes[1]) {
    case 0: // Reset Message
      return {
        "messageCount": {0: bytes[0] & 15},
        // See Common Message Protocols (linked in Wiki Article above) for sensor type definitions
        "sensorType": {0: bytes[2]},
        "hardwareVersion": {0: bytes[3]},
        "firmwareVersion": {0: (bytes[4] << 8) + bytes[5]}
      };
    case 1: // Supervisory Message
      var output = {
        "messageCount": {1: bytes[0] & 15},
        "supervisoryCodes" : {1: {
            // 0 for if no error, 1 if error
            "tamperDetected": {1: (bytes[2] & 16) === 16 ? 1 : 0},
            "currentTamper": {1: (bytes[2] & 8) === 8 ? 1 : 0},
            "downlinkError": {1: (bytes[2] & 4) === 4 ? 1 : 0},
            "batteryLow": {1: (bytes[2] & 2) === 2 ? 1 : 0},
            "radioError": {1: (bytes[2] & 1) === 1 ? 1 : 0}
          },
          "sensorState": {1: bytes[3]},
          // Battery level is the voltage value of the battery
          "batteryLevel": {1: ((bytes[4] & 240) / 16) + ((bytes[4] & 15) / 10)},
          // Total number of events since the last supervisory message
          "eventTotal": {1: bytes[8] * 256 + bytes[9]}}
      };
      if (typeof variables !== 'undefined' && 'radiobridgeModel' in variables) {
        switch (variables['radiobridgeModel']) {
          case 'RBS301-WAT-US':
          case 'RBS301-WR1M-US':
            output['waterNotLeaking'] = {8: bytes[5]};
            output['relativeResistance'] = {8: bytes[3]};
            break;
          case 'RBS306-ATH-EXT':
            var temperature = (bytes[5] & (1 << 7)) !== 0 ? (bytes[5] - 256) : bytes[5];
            output['temperature'] = {13: temperature + ((bytes[6] >> 4) / 10)};
            output['relativeHumidity'] = {13: bytes[7] + ((bytes[8] >> 4) / 10)};
            break;
          case 'RBS301-TEMP-EXT-US':
            output['temperature'] = {9: (bytes[3] & (1 << 7)) !== 0 ? (bytes[3] - 256) : bytes[3]};
            break;
        }
      }
      return output;
    case 8:
      // Water Sensor/Water Rope Sensor
      // 3rd byte is the event payload; 0 means water is leaking, 1 for water is not leaking
      // 4th byte is the relative resistance of the liquid
      return {
        "messageCount": {8: bytes[0] & 15},
        "waterNotLeaking": {8: bytes[2]},
        "relativeResistance": {8: bytes[3]}
      };
    case 9:
      // External Probe Temperature Sensor
      // 3rd byte is the event payload; consult user guide for definitions
      // 4th byte is the temperature reading in celsius
      // 5th byte is the relative temperature measurement (raw analog to digital measurement)
      var temperature = (bytes[3] & (1 << 7)) !== 0 ? (bytes[3] - 256) : bytes[3];
      return {
        "messageCount": {9: bytes[0] & 15},
        // Event Payload:
        // 0: Periodic Report
        // 1: Temperature has risen above upper threshold
        // 2: Temperature has fallen below lower threshold
        // 3: Report on change increase
        // 4: Report on change decrease
        "eventPayload": {9: bytes[2]},
        "temperature": {9: temperature},
        "relativeTemperature": {9: bytes[4]}
      };
    case 10: // Tilt Sensor
      // 3rd byte is the event payload; consult user guide for definitions
      // 4th byte is the tilt angle from the vertical axis. Small angles are closer to vertical,
      // large angles are closer to horizontal
      return {
        "messageCount": {10: bytes[0] & 15},
        // Event Payload:
        // 0: Sensor transitioned to vertical
        // 1: Sensor transitioned to horizontal
        // 2: Report on change toward vertical
        // 3: Report on change toward horizontal
        "eventPayload": {10: bytes[2]},
        "tiltAngleFromVertical": {10: bytes[3]}
      };
    case 13: // Air Temperature and Humidity Sensor
      var temperature = (bytes[3] & (1 << 7)) !== 0 ? (bytes[3] - 256) : bytes[3];
      return {
        "messageCount": {13: bytes[0] & 15},
        // Event Payload:
        // 0: Periodic Report
        // 1: Temperature has risen above upper threshold
        // 2: Temperature has fallen below lower threshold
        // 3: Temperature report on change increase
        // 4: Temperature report on change decrease
        // 5: Humidity has risen above upper threshold
        // 6: Humidity has fallen below lower threshold
        // 7: Humidity report on change increase
        // 8: Humidity report on change decrease
        "eventPayload": {13: bytes[2]},
        "temperature": {13: temperature + ((bytes[4] >> 4) / 10)},
        "relativeHumidity": {13: bytes[5] + ((bytes[6] >> 4) / 10)}
      };
    case 14: // Acceleration-based Movement Sensor
      // 3rd byte is the event payload; 00 for Movement Start, 01 for Movement Stop
      return {
        "messageCount": {14: bytes[0] & 15},
        "movementStop": {14: bytes[2]}
      };
    case 16: // Ultrasonic Level Sensor
      // 3rd byte is the event payload; consult user guide for definitions
      // 4th byte is the upper byte, 5th is the lower byte (in mm)
      return {
        "messageCount": {16: bytes[0] & 15},
        "distance": {16: bytes[3] * 256 + bytes[4]},
        // Event Payload:
        // 0: Periodic Report
        // 1: Distance has risen above upper threshold
        // 2: Distance has fallen below lower threshold
        // 3: Report on change increase
        // 4: Report on change decrease
        "eventPayload": {16: bytes[2]}
      };
    default:
      return {}
  }
}