The basic components of SHARKNET are: a GPS receiver, a depth/temperature sensor, an accelerometer, a cell phone module, a processor, a LED and a Bluetooth module.

When the user is at the surface, the GPS receiver monitors the geographical position and the phone module answers to any incoming text message from somebody (whom we left our number to) that is asking for our location.

When the dive begins, both GPS and cell phone signals are lost. The processor then turns off the phone and stores in memory the last GPS position fix as the starting point of our dive.

From this time on, every five seconds the processor stores the diver’s depth, temperature and attitude (standing/horizontal/upside down) as measured by the accelerometer. Upon resurfacing, SHARKNET reacquires a GPS fix, stores it as the final diving location and (with its phone module) automatically transmits all data to the SHARKNET server.

The SHARKNET server hosts a database with the information of each user. When the server receives a data file, it associates it to the user owning the device that transmitted the data. This way the user has his logbook always update.

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In case of emergency, when the user double taps SHARKNET, the accelerometer recognizes the double tap and notifies the processor. This makes the LED quickly flash and, if at the surface, the phone module transmits an alarm message to the server, that forwards it to all chosen addressees through text messages, phone calls or emails.

If the emergency is activated while underwater, the processor stores the alarm in the data file describing the dive and, once at the surface, it transmits the file to the server, that memorizes data into the user’s space and forwards the alarm to all addressees.

SHARKNET devices include a battery and, like any other component, is not accessible from the outside. Many are asking about the duration of the battery, but we don’t think it’s an issue. We try to explain the reason…

For the great majority of time, the device is in a sleep state, with minimal power consumption. Anytime it is kept still (in any position) for more than few minutes, the device gets asleep, to later wake up only when it senses a movement from the user.

When it’s awake, its power consumption varies a lot: it’s very low during dives (LED, GPS and phone are off), increases while at surface and reaches a maximum during data or text transmission.

For these reasons it’s very difficult to exactly say how long a battery lasts: it depends by the usage of the device. Broadly speaking, however, we don’t believe that a fully charged battery can last less than a day, even in the most challenging use scenarios. In conditions of “normal” use by a single user, the battery lasts a few days.

In any case, even when the battery gets discharged, its recharge is very easy. The device recharges wireless, just by having it sit onto its charging pad. A whole recharge cycle lasts a couple of hours. Additionally, the charge current is very small and the USB plug charging pad can be connected to any power supply for phones, directly to the PC or even (as shown in the photo) to a portable solar panel.

The device communicates with the user only through a LED:

• When the device is asleep, the LED is off. As it gets moved, the LED turns on in one of the following states.
• If the battery is close to discharge (starting from an hour to complete depletion), the LED flashes with a decreasing intensity, reminding a slow vanishing. When the battery is completely discharged, the LED is off.
• If the user forgot to recharge the credit of his SHARKNET device, the device notifies him with a sequence of three flashes followed by an off period of several seconds.
• When the device works normally, it emits a reassuring single flash every five seconds. While underwater, in any case, the LED is always off, not to scare fishes.
• In case of emergency, the LED flashes with a high frequency and intensity.

The user interacts with the device in an even easier way: a double tap activates the emergency; a further double tap deactivates it. All other SHARKNET operations are carried out in a fully automatic way.

We designed SHARKNET with the aim of having the user forget about it and just dive, as always.

At the beginning of the development we wondered which technology was more appropriate for data transmission: the one based on the cellular phone networks (GSM and later derivatives) or satellite.

Satellite transmission has the obvious advantage of global coverage, enabling the use even in the middle of the ocean. The disadvantage, however, is the high costs of both the satellite module and the subscription to data connection services. The cost of a satellite based SHARKNET would have been four times as much and the subscription no less than $25/month (and more, depending by the usage).

Since the above costs would have made SHARKNET a tool suitable only for professional use, we opted for the cellular technology, that nowadays has very affordable costs and a very wide world coverage.

Specifically, the service contracts of all major cellular providers grant a coverage that at sea extends up to 14 nautical miles from the coast. This coverage would be more than enough to fulfill the needs of most freedivers, scuba divers and others practicing sports at sea. All of us however know very well that the actual coverage (bot at sea and ashore) is not total and, most of the times, it varies from operator to operator.

In order to increase as much as possible the phone coverage, we selected for all SHARKNET devices a connection plan dedicated to communications among machines, that is agnostic with respect to the connection provider and allows devices to always lock to the cell with the highest power. In other words, even if the SIM is provided by a given connection provider (for example, AT&T) and a given area is covered by Verizon only or any other domestic or foreign provider, the device will always connect to the net that works the best.

This solution guarantees the highest service availability and, at the same time, keeps the cost of the device and the monthly subscription fee very reasonable.

It is not in fact the classic, expensive and never end tariff plans! Sharknet allows you to spend a few euros a month and above all to activate the credit only the months of real use of the device. Find the credit association process in the APP SETTINGS >> CHARGING MY MY SHARKNET section. First of all, you will need to load the credit in your App: just add the amount you prefer (eg € 20) through your PayPal account.

And then associate the amount you prefer for the period in which you want to activate Sharknet (eg € 10 for 30 days). If you are a diving center, you can use the same procedure for all the Sharknets in your possession and activate and deactivate the credit for each device according to your needs.

SHARKNET was conceived to be worn in a variety of different ways: on the mask’s strap, in the arm, on the BCD, in the weights’ belt, on the spear gun, or anywhere else. Any wearing position has its own pros and cons, and preference for any installation method depends on the use and personal preferences.

In order to allow the maximum usage flexibility, we designed SHARKNET so that it can be mounted into a plate provided with differently shaped holes, that allow its attachment to a variety of belts, laces and supports. We believe that this solution is simple and practical and allows users to easily adapt it to their needs.

Before making this solution (with its shape and holes) final, it would be very useful to discuss with you the installation method you are thinking about, possibly identifying the advantages and disadvantages of each of them. This way we’ll be able to build a mounting plate that can be as useful as possible.