It is not easy to define from which hardware components a dive computer made of. If you diassemble your dive computer, you will loose the warranty. The other caveat is once you assemble it once again, you have to pressure test it in a test chamber.

Unfortunately I don’t have a pressure chamber and I don’t want to disassemble my dive computer. Maybe someone else has already done it! I found a video and a disassembly guide about it online:

1. How Its made - Scuba Dive Computers
2. Suunto Vector disassembly photos and instructions

The Youtube video is an interesting one, because it shows how a real life Oceanic dive computer was manufactured and tested.

The following major hardware parts can be identified:

• Pressure sensor
• PCB = Printed Curcuit Board
• Microprocessor
• Memory
• Battery
• LCD screen
• Piezo buzzer
• Quarts crystal
• Watertight case
• Control buttons
• Bearing sensor (compass)

Let’s investigate each item in more details:

Pessure sensor

This sensor has to mesure the pressure of the surrounding water of the computer. The actual sensor sits at a bottom of a stainless steel cap. It is sealed from the water by some kind of gel, which transmits the pressure to the sensor, but protects the electronical parts.

Obviously the sensor has to measure absolute pressure in a range, which is suitable for a dive computer. Please remember that in each 10 meters (33 feet) below the surface the pressure will increase with 1 bar (1000 milliBar). It means that in 30 meters (100 feet) the pressure will be 4 bar (3 bars water + 1 bar air).

Besides the required range the sensor has to directly contact with water.

PCB and Microprocessor

The PCB (Printed Circuit Board) provides the electrical connection among the other components of the dive computer. For instance the microprocessor, which does all the required calculation, is soldered onto the PCB.

Usually it is a custom made circuit designed by another manufacturer and made exactly for the particular device version.

Memory

The dive computer has to contain two kinds of data:

1. Program data - control software and its settings
2. User data - previous dive data including the dive profile information

In some models the program data can be refreshed with a firmware update, which is about to apply bug fixes and enhancements done by manufacturer.

The user data can be downloaded for further analysis. The connection between the dive computer and another device can be made by a wired USB connection or through Bluetooth.

Obviously not only the physical access matters, but the data format. Almost all manufacturers have its own proprietary data format.

Battery

The battery has to provide enough juice for the device to be operable under water during the dive and on the surface, because the surface intervals have to be measured between the dives.

It also has to be repleacable. The best case is when it is repleacable by the diver. The other option is that you have to bring your computer to the appropriately certified service center, buy the replacement kit and pay an extra fee for the service.

It is quite dangerous when you run out of battery power under water, therefore the manufacturers build into warnings and power consumption displays into the computers.

LCD Screen

This is one of the most important parts of the device. It should be large, bright and the view angle should be great.

Usually it is monochrome, because it consumes less energy than a color screen. On monochrome displays the backlight is essential in case of low visibility dives - e.g. night and wreck diving.

Touch screens do not work under water!

Piezo buzzer

This part makes sound. The main purpose of it is to warn the diver, if something unusual happens during the dive. It can be replaced by a small vibrating motor, but to be honest sound travels fast in water, so it can be heared much better than to feel the vibration in a thick scuba diving suit.

Quarts crystal

Dive computers have to measure the duration of the dive or the various stops under the water. For this reason a quarts crystal can be used.

The loogbook also tracks the exact date of the dive, so a quarts crystal comes handy in this case as well.

Watertight case

This is the most essential part of the dive computer. All the electronic parts have to be kept away from water contact. It also has to cope with high pressure.

Usually it is made from plastic, but for better durability the technical dive computers are made from aluminium.

Control buttons

The diver has to interact with the computer somehow. It can be done by buttons. The speciality here is that these buttons have to be sealed from water. This is the most dangerous part of the watertight case, because the diver will press these buttons frequently and if the sealing o-ring goes wrong the water will get into the case.

The less functionality you have the less buttons you need, therefore on cheap dive computers you can find only one or two buttons.

Extras

There are many extras, which can be added to the dive computers:

1. Bearing sensors - to simulate a compass
2. Wireless tank pods - to measure your air consumption
3. Bluetooth adapter - to be able to sync with your mobile
4. Light sensor - to adjust the brightness of the LCD and turn night mode on/off
5. Infrared sensor - to communicate with your device