Acousonde™ Tips & Tricks
Updated 9 April 2013
Following some rules of thumb can
improve your experience with the Acousonde. Here are a few less-than-obvious techniques.
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Break in batteries that have been on the shelf
- Lithium primary cells that have been in storage for months or longer, particularly in warm
temperatures and especially if used before storage,
may have accumulated a form of internal resistance known as a passivation layer.
Using the battery will gradually break down this layer, but not without initial risk of
premature failure due to this temporary resistance. To "break in" a battery
suspected of passivation
we recommend placing the battery in the Acousonde backwards, thereby operating the
reverse-battery warning light, for 5 to 10 minutes before use.
This should not be necessary for fresh, newly manufactured batteries.
Ensure battery surface is clean and dry
- Contaminants on the battery surface, particularly when combined
with condensation due to excessive moisture inside the battery
may increase power leakage from the
battery and shorten deployment life. If the battery has not been kept clean and dry,
it may be necessary to wipe the entire battery
surface with an alcohol-moistened tissue.
Insert battery under driest conditions possible
- When inserting the battery
and sealing the housing, do so under the driest conditions
possible, especially for deployments in cold water. This
will limit the risk of condensation inside the housing.
Clean the battery contacts
- Dirty contacts in the
Acousonde battery compartment or on the battery itself can
introduce resistance that will shorten deployment life.
Clean all Acousonde and battery contacts before deployment
by lightly swabbing with isopropyl alcohol.
Use high-purity alcohol for cleaning
- Isopropyl alcohol, while a fine cleaning agent for
battery contacts, is often found in solutions including
up to 30% water. The water may take much longer
to evaporate than the alcohol, leading to the risk of excess
humidity and condensation within the battery compartment and
consequently shorter deployment life.
Use the highest-purity isopropyl alcohol available to clean
Grease the threads
- Bare aluminum oxidizes immediately on contact with air,
leaving a microscopic insulating layer.
To discourage the formation of this insulation on the threads
of the battery housing and battery cap, do not clean
the threads without
regreasing them with silicone grease. If in doubt,
screw the battery cap all the way in a few times
after greasing, while at the same time
pulling on the battery cap, to mechanically
wear off any existing oxidation.
Use a compliant spacer to secure the battery
- The battery housing is designed to accommodate
batteries whose length is at the upper limit of manufacturer
tolerance. Most batteries are shorter than this and
will be able to move within the housing. To minimize
battery movement, place a compliant spacer -- such as
a nylon washer, or an o-ring selected or cut to fit --
in the bottom of the battery cap. This will help
restrict movement of the battery during deployment.
Tighten the battery cap very securely
- A secure ground connection depends on tight electrical
connection through the battery housing threads.
Motion combined with changes in pressure and temperature
may cause the
threads to loosen slightly, creating a power-failure risk.
To discourage this, tighten the
battery cap well.
To tighten the "dome" battery caps that come with the
Acousonde 3B, we recommend using a jumbo
flat screwdriver to get sufficient leverage. For the cylindrical caps that
come with the Acousonde 3A, we recommend using
a rubber mitt, or wrapping the cap in self-vulcanizing
rubber tape, to allow you to grip it tightly without slipping.
We are planning to add flats to new 3A battery caps
to allow use of a wrench.
Check float-retention tabs on the 3B
- The glue used to secure the Acousonde 3B float-retention
tabs has survived over a month of seawater soaking
as well as freeze-thaw cycling. We believe it to be
a permanent attachment. However it
does not hurt to verify that the tabs are secure before
deploying the instrument. If by chance a tab attachment
point is loose, use a swab soaked in isopropyl alcohol
to clean the contact areas of the tab and the urethane,
wait for them to dry,
and insert a small amount of superglue to reattach.
Consider a grip-retention lanyard
- If the deployment grip you are using
could separate from your attachment pole,
the weight of the grip would overcome the
flotation attached to the tag and the entire
assembly could be lost at sea. If there seems
any chance of the deployment grip separating,
use a lanyard to tie the grip to a secure location
on the deployment pole.
Serial numbers B003A003-4 and B003A007-12: tape front end
- These eight Acousonde 3A units contain a component that
is sensitive to very bright sunlight and incandescent light. If the
component is exposed to this kind of light when the instrument
is first powered up or when sampling is started -- including an
unattended delayed start -- the hardware may
fail to operate, the operating system will shut down,
and full removal and reapplication of power may be necessary
(an ordinary magnetic-switch reset may not be enough).
The problem is avoided by wrapping black tape circumferentially around
the 3A in the region of the component,
located on the same side of the instrument as the pressure transducer about
4.2 cm (1 5/8") back from the hemispherical
leading edge of the urethane encapsulant. About 4 cm
(1 1/2") width of tape coverage, centered on the component's position, should
suffice to shade it; it is not necessary to wrap the entire unit. This is only recommended
for the specific units stated! The issue has been
fixed in later units.
Verify correct clock setting
- The Control page of the PalmOS command
application shows the Acousonde's time-of-day setting
after every infrared interaction with the Acousonde.
Use this indication to check if the Acousonde has
been successfully set to the correct time.
Verify operation using top-of-minute LED flash
- The Acousonde produces a visual indication of status
at the top of every minute. Do not deploy the Acousonde
without waiting for at least one top-of-minute indication
to verify correct operation (as well as correct alignment
of the Acousonde's clock).
Offload one volume at a time
- It is possible to ask a USB host Mac OS X or Windows
computer to offload data from multiple volumes of a given
Acousonde simultaneously; however, we strongly discourage this.
Simultaneous offloading can take much longer
than offloading one volume at a time and may wear out the
storage cards prematurely.
This is because an Acousonde is not able to power or
communicate with more than one of its storage cards at a time.
Multiple storage volumes do appear to be mounted on the
USB host computer but this is a kind of illusion. In reality all but one of
the underlying storage cards are
If asked to offload data from multiple volumes
simultaneously via USB, the Acousonde must frenetically power
its storage cards on and off to maintain the illusion. Each time a card
is turned on, data transfer must be suspended until the lengthy card-restart process
completes. Thus, if asked to transfer data from multiple volumes simultaneously,
the Acousonde may spend more time waiting for card-restart
to complete than it does actually reading card data.
Data transfer from a given Acousonde is much faster, not to mention
easier on the equipment, when done one volume at a time.
Identifying a suitable spare or replacement MicroUSB-to-USB cable
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Use a MicroUSB-to-USB cable that is fully wired for data
- Some MicroUSB cables for mobile phones and related appliances
provide only power, not data. These cables may look usable, and
indeed may fit in the Acousonde
and allow it to boot normally; however, the contents of the
Acousonde will not be accessible from your personal computer.
Get a MicroUSB-to-USB cable that fits in the battery housing
- The Acousonde battery housing cannot accommodate all MicroUSB-to-USB cables.
Some cables' finger-grip section, molded around the MicroUSB plug, is
too large to fit in the housing while still allowing the plug itself to
mate with the MicroUSB socket at the housing's deep end. Such cables cannot
be used with the Acousonde.