Petrel-X User Manual 1.1
11
Water Sensing
The Petrel-
X’s water sensor is used to detect whether it is above water or submerged. The sensor
measures the resistance between the antenna and the electronics head. When the Petrel-X is
above water, the water sensor is not used. The water sensor will only begin measuring once the
unit enters underwater mode in an effort to detect surfacing events.
The water sense reading has to be
lower
than the threshold number when submerged, and
higher than the threshold number when surfaced for surfacing to take place. Freshwater
environments can vary in the reading given. Therefore, testing should be done ahead of
freshwater deployments to ensure proper operation.
Tilt Sensing
In some applications, a Petrel-X may be installed on a device whose orientation changes when it
is surfacing compared to when it is staying submerged. A Petrel-X can be configured to use
internal orientation sensing as a replacement for its conventional water sensing.
When tilt-sensing is enabled (using the
$usetilt 1
command), the Petrel-X will perform tilt
checks
instead
of normal water-sense checks. When using tilt-sensing instead of water-sensing,
being upright (antenna pointed towards the sky) is considered
Surfaced
and will cause the unit
to go to GPS Search Mode. The Petrel-X will stay in underwater mode if it is kept inverted
(antenna pointed towards the earth). Tilt checks are performed with the same schedule and
timing as water checks.
The cutoff between upright and inverted is approximately 120 degrees from the upright
position. So a Petrel-X will consider itself upright rather than inverted if it is laid down
sideways, since that is only 90 degrees off from being upright.
When using tilt sensing, the conventional water sense is not used. The Petrel-X can only use
one or the other.
Bluetooth
The Petrel-X has integrated Bluetooth hardware to facilitate local communication with the user
for configuration and firmware upgrades via the
The Petrel-
X’s Bluetooth will advertise while in Bluetooth mode, after boot. When a Bluetooth
connection is established, the unit will flash its green LED several times.
Bluetooth mode normally lasts for 2 minutes after the unit is turned on. If a Bluetooth connection
is established, the unit will not exit Bluetooth mode until at least 1 minute has passed since the
last Bluetooth session ended.