HWB Standard

HWB Standard

MQTT topic and payload specifications for hardware devices and sales clients.

Technical documentation and specifications for message exchanges between hardware devices and sales clients in bus. All communication is to be done through MQTT with JSON as payload.

Scope of this specification is primarly for Møre og Romsdal Fylkeskommune and FRAM, but the overall ambition is for a broad consensus with other operators and authorities.

API Specifications NFC Flow diagram

Topic specifications

/
├── device
│    ├── [deviceId]
│    │    └── diagnostics
│    │         └── request
│    └── diagnostics
│         └── request
├── sensors
│    └── location
└── validators
     ├── [deviceId]
     │    ├── configure
     │    │    ├── current
     │    │    └── request
     │    └── response
     ├── barcode
     ├── configure
     │    ├── current
     │    └── request
     └── nfc
          └── apdu
               ├── [deviceId]
               │    └── transmit
               └── receive

Hardware topology

All communication happens through a local MQTT Broker, eg. a hardware gateway. Newer versions of ITxPT also specifies MQTT as a standard way of interacting with devices.

  ---
  title: Component connections w/protocols
  ---
  
  graph TB
  
      subgraph terminal
      A("Sales Client\n(Client)")
      end
      A <--MQTT--> B("Gateway\n(Broker)")
  
      subgraph READERS
          D("Barcode/NFC\n(Device)")
          E("Barcode/NFC\n(Device)")
          F("Barcode/NFC\n(Device)")
      end
  
      B <--MQTT--> READERS
      B<--MQTT-->G("GPS\n(Device)")
  
      B<-.MQTT.->C("APC\n(Device)")
  
      style C opacity:0.7,stroke-dasharray: 4

Terminology

  • Client: Sales client used by operators.
  • Broker: Local running MQTT Broker that relays all messages.
  • Device: Hardware devices in bus communicating with sales client.

Prior work

Other similar work that is used as inspiration.