Measurement Cycle

This diagram shows how the Multiflexmeter collects and sends sensor data.

%%{init: {'theme':'base', 'themeVariables': { 'fontSize':'16px'}}}%%
flowchart TD
    Start([Device Powers On]) --> Init["Initialize Hardware
Setup I2C, SPI, GPIO"]
    Init --> LoadCfg["Load Configuration
Read EEPROM (41 bytes)
DevEUI, AppKey, Interval"]
    LoadCfg --> JoinNetwork["Join LoRaWAN
OTAA Activation
5-10 seconds"]
    JoinNetwork --> WaitJoin{"Network
Joined?"}
    WaitJoin -->|Failed| Retry["Wait 60s
Backoff Retry"]
    Retry --> JoinNetwork
    WaitJoin -->|Success| FirstDelay["Initial Delay
45 seconds
Version Ping"]

    FirstDelay --> Schedule["Schedule Next
Interval: 20-4270s"]
    Schedule --> Sleep["Sleep Mode
Low Power
Conserve Battery"]
    Sleep --> WakeUp["Timer Expires
Wake Up"]
    WakeUp --> PowerSensor["Power On Sensor
GPIO Control"]
    PowerSensor --> Trigger["Trigger Measurement
I2C CMD 0x10
to address 0x36"]
    Trigger --> Wait10["Wait 10 Seconds
Sensor Processing"]
    Wait10 --> Read["Read Sensor Data
I2C CMD 0x11
Get measurement bytes"]

    Read --> ValidData{"Data
Valid?"}
    ValidData -->|Error| LogError["Log Sensor Error
NACK or Timeout"]
    LogError --> PowerOff1["Power Off Sensor
Save Power"]
    PowerOff1 --> Schedule
    ValidData -->|Valid| Transmit["Send via LoRaWAN
Port 1: Sensor Data
868MHz, SF7-SF12"]

    Transmit --> RX["Open RX Windows
RX1 @ 1s, RX2 @ 2s"]
    RX --> CheckDownlink{"Downlink
Received?"}
    CheckDownlink -->|No| PowerOff2["Power Off Sensor"]
    PowerOff2 --> Schedule
    CheckDownlink -->|Yes| ProcessCmd["Decode Command
Parse Payload"]

    ProcessCmd --> CmdType{"Command
Type?"}
    CmdType -->|"0xDEAD"| ResetCmd["Reset Command
Enable Watchdog
15ms timeout"]
    ResetCmd --> Reset([💥 Device Resets])
    CmdType -->|"0x10 [MSB][LSB]"| IntervalCmd["⏱️ Update Interval
Bounds: 20-4270s
Save to EEPROM"]
    IntervalCmd --> PowerOff3["🔌 Power Off Sensor"]
    PowerOff3 --> Schedule
    CmdType -->|"0x11 [data...]"| ForwardCmd["📤 Forward to Sensor
I2C Write to 0x36
Custom command"]
    ForwardCmd --> PowerOff4["🔌 Power Off Sensor"]
    PowerOff4 --> Schedule

    %% Styling
    style Start fill:#e8f5e9,stroke:#2e7d32,stroke-width:3px
    style Reset fill:#ffcdd2,stroke:#c62828,stroke-width:3px
    style Sleep fill:#e3f2fd,stroke:#1565c0,stroke-width:2px
    style Transmit fill:#fff3e0,stroke:#e65100,stroke-width:2px
    style Schedule fill:#f3e5f5,stroke:#6a1b9a,stroke-width:2px

    style Init fill:#b2dfdb,stroke:#00695c,stroke-width:2px
    style LoadCfg fill:#b2dfdb,stroke:#00695c,stroke-width:2px
    style JoinNetwork fill:#b2dfdb,stroke:#00695c,stroke-width:2px
    style FirstDelay fill:#b2dfdb,stroke:#00695c,stroke-width:2px

    style PowerSensor fill:#ffe082,stroke:#f57f17,stroke-width:2px
    style Trigger fill:#ffe082,stroke:#f57f17,stroke-width:2px
    style Read fill:#ffe082,stroke:#f57f17,stroke-width:2px
    style Wait10 fill:#ffe082,stroke:#f57f17,stroke-width:2px

    style ResetCmd fill:#ef9a9a,stroke:#c62828,stroke-width:2px
    style IntervalCmd fill:#ce93d8,stroke:#6a1b9a,stroke-width:2px
    style ForwardCmd fill:#90caf9,stroke:#1565c0,stroke-width:2px

    style LogError fill:#ffccbc,stroke:#d84315,stroke-width:2px
    style WaitJoin fill:#fff9c4,stroke:#f57f17,stroke-width:2px
    style ValidData fill:#fff9c4,stroke:#f57f17,stroke-width:2px
    style CheckDownlink fill:#fff9c4,stroke:#f57f17,stroke-width:2px
    style CmdType fill:#fff9c4,stroke:#f57f17,stroke-width:2px

Key Points

• Measurement interval: Configurable between 20 seconds and 4270 seconds (~71 minutes)
• Power management: Device sleeps between measurements to save battery
• Downlink commands:
  • 0xDEAD: Reset device
  • 0x10: Change measurement interval
  • 0x11: Forward command to sensor module