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Site Telemetry

The OT2 tracker includes built-in telemetry features:

  • Telemetry 1: Internal temperature sensor
  • Telemetry 2: Voltage divider (power supply voltage)
  • Telemetry 3: Analog input on MON08 pin 10
  • Telemetry 4: Pulse counter input (accessory port pin 1 or MON08 pin 6)
  • Telemetry 5: GPS HDOP
  • Digital Bit 7: External digital input (accessory port pin 6)

With minimal interfacing, these allow for comprehensive remote site monitoring.

Telemetry Input Uses

  • Temperature (Input 1): Measures internal case temp. Useful for HVAC status, though values are slightly elevated from electronics heat.
  • Voltage (Input 2): Monitors power supply or backup battery stack.
  • Input 3: Can monitor a second battery stack using an additional voltage divider.

Voltage Divider

  • Input 4: Wired to a reed switch on the shack door to detect intrusion.

Accessory wiring

  • Digital Input 7: Connected to a relay powered by site AC, enabling power failure detection.

All values can be visualized on telemetry graphs at aprs.fi.

Scripting

The real power of telemetry is in the scripting engine. With it, you can send email alerts based on monitored conditions and change profiles for automated behavior.

Profile-Based Voltage Monitoring

If voltage drops below 11V, switch to Profile 2 and send an alert.

If Profile 2
  Do Once
    If Flags 0xxxxxxx
      Exec "SEND EMAIL someone@email.com This site Low Voltage"
      Toggle Flags 10000000
    End Block
  End Block
End Block

Door Alarm (Pulse Count)

Sends an alert if door is opened (pulse detected).

If Pulse Count > 1
  Do Once
    If Flags x0xxxxxx
      Exec "SEND EMAIL someone@email.com This site Door Alarm"
      Toggle Flags 01000000
    End Block
  End Block
End Block

AC Power Outage & Recovery

Uses Peek 3 to check bit 7. Waits 5 minutes of outage or 10 minutes of recovery before triggering alerts.

If Peek 3 and 64 = 64
  Set Counter 2 = 0
  On Second
    Increment Counter 1
    If Counter 1 = 300
      If Flags xx0xxxxx
        Exec "SEND EMAIL someone@email.com This site AC Alarm"
        Toggle Flags 00100000
      End Block
    End Block
  End Block
Else
  Set Counter 1 = 0
  On Second
    Increment Counter 2
    If Counter 2 = 600
      If Flags xx10xxxx
        Exec "SEND EMAIL someone@email.com This site AC Back On"
        Toggle Flags 00010000
      End Block
    End Block
  End Block
End Block

Alarm Acknowledgment

Resets alarm flags and pulse counter manually.

Macro ALARMACK
  Set Flags 00000000
  Set Pulse Count = 0
  Exec "SEND N0CALL Alarm Ack"
End Block

Interfacing

I/O Interface

The interface consists of binding blocks for easy access:

  • AC relay for power loss detection
  • Screw terminals for door alarm and battery stack
  • Additional relay controlled by POWER command
  • Relay isolates switched power from OT2 circuitry

With this setup, the OT2 becomes a powerful and flexible site monitoring and alerting system.