Internal Leak Failsafe

If sub is equipped with a leak detector internally, then a failsafe can be enabled when a leak is detected. Sub provides the ability to have up to three detectors. Each detector can be either analog or digital. When a leak from any detector is detected, a failsafe can be enabled to occur.

For the remainder of this article, the first leak detector’s parameters will used for example.

When the failsafe will trigger

If FS_LEAK_ENABLE is non-zero, and a detector is attached to either an analog input or GPIO pin on the autopilot, set by the LEAK1_PIN. Then if the detector is analog, it’s considered active (“1”) if its voltage is > 2.0V. Digital sensors present a normal digital logic level.

Whether the active level of an analog sensor or the logic level from a digital sensor is taken as “dry” is determined by the LEAK1_LOGIC parameter.

Note

In ArduSub firmware prior or equal to 4.5, the input pin must be declared to be analog or digital with the LEAKx_TYPE parameter.

Note

Digital leak detectors should be connected to digital input pins. Some flight controllers support that on servo channel ports, in which case the relevant channel(s) must be configured as GPIOs.

What will happen

When the failsafe occurs, the action taken is determined by the value of FS_LEAK_ENABLE:

• Disabled (Value 0) will disable the failsafe entirely.

• Warn Only (Value 1) will send a “Leak Detected” GCS warning message.

  • On a flight controller with notifying hardware, status LEDs will flash yellow and white, and the buzzer will play a cycle of falling tones

• Enter SURFACE Mode (Value 2) will send a warning and return the vehicle to the surface.