1. DIVE COMPUTERS
Insert Shop Name Here

2. How a Computer Works Liquid Crystal
Display
Step 3. The microprocessor takes depth, pressure and time data and performs calculations and outputs the information to the LCD.
Liquid
Crystal
(LCD)
Step 4. Process repeats every second.
Clock
Step 2. A/D converter changes voltage into numbers that the microprocessor can use. Elapsed time is also sent.
Micro
processor LP
Transducer
(Depth)
Temp
Sensor HP
(Tank Pressure)
Step 1. Sensors send voltage information to the Analog to Digital (A/D) converter.
A/D
Converter

3. Tables vs. Computers Tables based on square profiles.
Allowable dive time based on maximum depth, no matter how long you stay there (1 minute or 20 minutes).

4. Tables vs. Computers

5. Basic Theory
Tissue Compartments - Mathematical models used in the computer algorithm
Nitrogen Tolerance - How much nitrogen pressure a tissue can absorb
Half Times - The amount of time it takes the tissue to fill by one half.

6. Tissue Compartments

7. Fast 5 minutes

8. Fast 10 minutes

9. Fast 15 minutes

10. After 6 half times The tissue compartment is considered full
The computer will prescribe required decompression stops

11. Tissue Loading in Action Using Suunto Dive Manager (click on screen to start/stop; click off screen to go to next slide)

12. Types of Computers
Standard
Wristop
Air Integrated
Hoseless

13. Standard Computers Basic Features Current Depth No decompression time
Max depth
Bottom Time
Ascent Rate
Logbook memory
Pre-dive planning
Nitrox
Suunto Gekko

14. Standard Computers Advanced features Electronic backlight
Dive simulator
Plan Simulator
PC Download
Bookmarking
Suunto Vyper

15. Wristop Computers Basic & Advanced features
< Stinger
Basic & Advanced features
Multi-purpose – not just for diving
Always with you
Freediving features
Mosquito >

16. Air-Integrated Computers
Same features as basic computer
More accurate pressure than analog gauges
Calculates air-time remaining

17. Hoseless Computers Includes same features as air-integrated computers
Transmitter sends pressure info via radio wave
Specially coded to prevent interference from other hoseless computers

18. Demonstrated with the Suunto
USING A DIVE COMPUTER
Demonstrated with the Suunto

19. Button Interface Mode (Menu) Activate Smart button
Use bezel labels when no LCD prompts

20. Button Interface Smart button Select: Enter the mode
LCD prompts override bezel prompts
Select: Enter the mode
Quit: Exit a mode or menu
OK: Accept the setting

21. Button Interface Plan Button Puts computer in Dive Planning Mode
Time Button Switches bottom display to show time of day

22. Button Interface Up Button Scrolls up or increases value
Down Button Scrolls down or decreases value

23. Click on video clip to start & stop
Manual Activation
Press On (Mode) Button
All segments displayed
Battery Check
Click on video clip to start & stop

24. Battery Check
4 segments: Normal, full battery

25. Battery Check
3 segments: Normal, battery is getting low or temperature is low. Battery replacement is recommended for cold conditions or dive trip

26. Battery Check
2 segments: Power is low and replacement recommended. LOWBAT warning and icon displayed.

27. Battery Check
1 segment: Change the battery. Activation and functions disabled.

28. Automatic (Water) Activation
Electrical connection between interface contacts and buttons
Starts automatically when submerged

29. Automatic (Water) Activation
AC = Active Contacts
Displays Time and Date
Goes to dive mode when deeper than 5 feet

30. Click on video clip to start & stop
Time Display
Press TIME button
Toggles dive time & pressure with Time of day and temperature
Click on video clip to start & stop

31. EXERCISE #1
Manually activate computer
Change time display

32. Dive Planning
Allows you to scroll through depths in 10-foot increments and see the maximum dive times for each depth.
The dive plan constantly updates as you extend your surface interval between repetitive dives.

33. Dive Planning Press Plan Button Mode indicated by “PLAN”
Use bottom buttons to scroll
Press smart button to quit
Click on video clip to start & stop

34. EXERCISE #2 Plan a dive to 100 feet
What is the no-decompression limit?
ANSWER: 17 minutes

36. Click on video clip to start & stop
Memory Modes
LOGBOOK
50 hour memory
Four pages for each dive
Profile read out
HISTORY
Max depth ever reached
Total dive time hours
Total dives
PC SET
Reset feature (shop only)
Click on video clip to start & stop

37. EXERCISE #3 Go to MEMORY > HISTORY
On your computer, what is the total dive hours? Number of dives? Maximum depth?

38. Set Modes SET MODEL SET ALARMS SET TIME SET ADJSTMENTS Air/Nitrox.
Dive time alarm
Depth alarm
SET TIME
Time, Date, Alarm Clock
SET ADJSTMENTS
Altitude adjustment
Personal adjustment
Metric/Imperial
Click on video clip to start & stop

39. QUICK QUIZ #1
What are the two main menu modes?
ANSWER: SET and MEMORY

40. Dive Mode Display Current Depth Maximum Depth No Decompression Time
Dive Time
Temperature
Consumed Bottom Time

41. Dive Mode Display
Notice how going deeper decreases the allowable no decompression time.

42. Dive Mode Display
Notice how going deeper decreases the allowable no decompression time.

43. Dive Mode Display Consumed Bottom Time (CBT)
As no-decompression time decreases, more segments on the CBT appear. The graph is color coded green, yellow & red, giving you a quick visual reference of your no-decompression time.

44. Dive Mode Display Consumed Bottom Time (CBT)
RED ZONE: 0 minutes; deco stops required 5
YELLOW ZONE: 10 – 5 minutes 10 20 30 40 50 60 80
100
GREEN ZONE: minutes
200

45. Dive Mode Display

46. Dive Mode Display Maximum Depth Locks In
Notice how the maximum depth reading stays at 100 after ascending to a shallower depth

47. Dive Mode Display Ascent Rate Bar Graph
The diver just ascended from 100 feet to 60 feet in less than a minute. This causes the ascent rate bar graph to fill up…

48. Dive Mode Display Ascent Rate Bar Graph >39 ft/min. 33-39 ft/min.

49. EXERCISE #4
Using dry-erase Gekko display, fill in the display using the following dive information:
Depth = 100 ft
Max depth = 120 ft
No-decompression time = 5 minutes
Dive time = 12 minutes
Ascent rate = 2 segments
Temperature = 65°F
CBT = 10 segments

50. Dive Mode Display Multilevel Diving in Action
No Dec Time counts down as you remain at the same depth
No Dec Time increases as you ascend to a shallower depth

51. Dive Mode Display Multilevel Diving in Action
No Dec Time counts down as you remain at the same depth
No Dec Time increases as you ascend to a shallower depth

52. Dive Mode Display Multilevel Diving in Action
No Dec Time counts down as you remain at the same depth
No Dec Time increases as you ascend to a shallower depth

53. Dive Mode Display Multilevel Diving in Action
No Dec Time counts down as you remain at the same depth
No Dec Time increases as you ascend to a shallower depth

54. Dive Mode Display Multilevel Diving in Action
No Dec Time counts down as you remain at the same depth
No Dec Time increases as you ascend to a shallower depth

55. Dive Mode Display Multilevel Diving in Action
No Dec Time counts down as you remain at the same depth
No Dec Time increases as you ascend to a shallower depth

56. Dive Mode Display Multilevel Diving in Action
No Dec Time counts down as you remain at the same depth
No Dec Time increases as you ascend to a shallower depth

57. Dive Mode Display Multilevel Diving in Action
No Dec Time counts down as you remain at the same depth
No Dec Time increases as you ascend to a shallower depth

58. Dive Mode Display Multilevel Diving in Action
No Dec Time counts down as you remain at the same depth
No Dec Time increases as you ascend to a shallower depth

59. Dive Mode Display Multilevel Diving in Action
No Dec Time counts down as you remain at the same depth
No Dec Time increases as you ascend to a shallower depth

60. Dive Mode Display Multilevel Diving in Action
No Dec Time counts down as you remain at the same depth
No Dec Time increases as you ascend to a shallower depth

61. Dive Mode Display Multilevel Diving in Action
No Dec Time counts down as you remain at the same depth
No Dec Time increases as you ascend to a shallower depth

62. Dive Mode Display Multilevel Diving in Action
No Dec Time counts down as you remain at the same depth
No Dec Time increases as you ascend to a shallower depth

63. Dive Mode Display Multilevel Diving in Action
No Dec Time counts down as you remain at the same depth
No Dec Time increases as you ascend to a shallower depth

64. Dive Mode Display Multilevel Diving in Action
No Dec Time counts down as you remain at the same depth
No Dec Time increases as you ascend to a shallower depth

65. Dive Mode Display Multilevel Diving in Action
No Dec Time counts down as you remain at the same depth
No Dec Time increases as you ascend to a shallower depth

66. Dive Mode Display Multilevel Diving in Action
No Dec Time counts down as you remain at the same depth
No Dec Time increases as you ascend to a shallower depth

67. Dive Mode Display Multilevel Diving in Action
No Dec Time counts down as you remain at the same depth
No Dec Time increases as you ascend to a shallower depth

68. Dive Mode Display Multilevel Diving in Action
No Dec Time counts down as you remain at the same depth
No Dec Time increases as you ascend to a shallower depth

69. Dive Mode Display Multilevel Diving in Action
No Dec Time counts down as you remain at the same depth
No Dec Time increases as you ascend to a shallower depth

70. Dive Mode Display Multilevel Diving in Action
No Dec Time counts down as you remain at the same depth
No Dec Time increases as you ascend to a shallower depth

71. Dive Mode Display Multilevel Diving in Action
No Dec Time counts down as you remain at the same depth
No Dec Time increases as you ascend to a shallower depth

72. Dive Mode Display Multilevel Diving in Action
No Dec Time counts down as you remain at the same depth
No Dec Time increases as you ascend to a shallower depth

73. Dive Mode Display Multilevel Diving in Action
No Dec Time counts down as you remain at the same depth
No Dec Time increases as you ascend to a shallower depth

74. Dive Mode Display Recommended Safety Stop
Ascending above 20 feet triggers the safety stop feature. The word “STOP” appears and safety stop timer counts down from 3 minutes to 0 minutes.

75. Dive Mode Display Recommended Safety Stop
Ascending above 20 feet triggers the safety stop feature. The word “STOP” appears and safety stop timer counts down from 3 minutes to 0 minutes.

76. Dive Mode Display Recommended Safety Stop
Ascending above 20 feet triggers the safety stop feature. The word “STOP” appears and safety stop timer counts down from 3 minutes to 0 minutes.

77. Dive Mode Display Recommended Safety Stop
When two dashes appear (- -), it is OK to surface.

78. Dive Mode Display

79. Surface Mode Display – Screen 1
No Fly Icon
When the No Fly icon appears, you should avoid flying in a commercial aircraft until the icon disappears.

80. Surface Mode Display – Screen 1
Diver Attention Symbol
When the Diver Attention Symbol appears, you should extend your surface interval before doing the next dive.

81. Surface Mode Display – Screen 1

82. Surface Mode Display – Screen 2
Surface Time
Surface time is the amount of time you have been out of the water after making a dive

83. Surface Mode Display – Screen 2

84. Surface Mode Display – Screen 3
No Fly Time
No fly time is the amount of time you have to wait before flying on a commercial airliner.

85. Safety Guidelines for Computer Assisted Diving

86. Read the Manual Before Diving
Each dive computer has its own special parameters of operation and usage limitations.
The importance of proper training in the operation of the dive computer cannot be overemphasized.

87. Each Diver Should Always Have Their Own Dive Computer
Sharing computers is dangerous!

88. Dive Conservatively with Respect To the No-Decompression Limits

89. Perform Only No-Deco Dives
Situations requiring direct ascent to the surface while in decompression mode are a potential problem causing decompression sickness. These situations might include:
Insufficient air supply to make any required decompression stops.
Emergencies such as running out of air, rupturing an air hose or having a buddy run out of air.

90. Do Not Exceed the Computer Specified Ascent Rate
All Ascents Should Be Slow!
Always monitor the dive computer during ascent.

91. Make A Safety Decompression Stop On Every Dive
Safety stops are beneficial in the prevention of decompression sickness.
A safety stop should be made on every dive at approximately 5m/15ft for three to five minutes

92. Avoid Reverse Profiles
Multi-level dives should be initiated with the deepest segment of the dive first and subsequent portions of the dive made in progressively shallower depths.

93. Avoid Repetitive Deep Dives
Repetitive dives to depths in excess of 30m/100ft should be avoided.

94. Do Not Reset Computer Until Out-Gassing Is Complete
A dive computer should never be reset or turned off between dives or before it has calculated out gassing.
(Most computers today will not allow you to turn them off until they have completed off gassing.)

95. Dive Computer Failure Procedures
There are two possible failure situations:
The dive computer could fail during a dive, or
it might fail during a surface interval.

96. Procedure For Computer Failure During A Dive
Ascend immediately; do not to exceed computers ascent rate.
Make a safety stop at 5m/15ft for three to five minutes to add a safety margin.
If computer fails while in a decompression mode, proper decompression stops cannot be monitored. Another reason to avoid decompression diving.

97. Procedure For Computer Failure Between Dives
Three options for handling a computer failure during a surface interval:
Make a single repetitive dive using the adjusted no-decompression limit given by the computer during its surface scrolling mode (Plan Mode).
Repetitive dives could be made to depths less than 6m/20ft.
End the day’s diving activities.

98. Procedure For Computer Failure Between Dives
It is recommended that there should be no diving within 24 hours prior to using a new computer or a computer that has been turned off since a previous full day of diving may have left the body with a significant amount of residual nitrogen.

99. Drinking Alcohol and Computer Diving Do Not Mix
Increased susceptibility to decompression sickness due to dehydration and changes in blood characteristics.

100. Flying After Diving Procedures
Many dive computers feature flying after diving indicators which tell a diver when it is safe to fly.
Most allow a diver to fly within a short period of time following a day’s diving activities.
Many authorities recommend that recreational divers wait 24 hours after diving before flying to add a safety margin.

101. Summary of Dive Computer Guidelines
Read the Operation Manual Thoroughly.
Each Diver Should Have Their Own Dive Computer.
Dive Conservatively With Respect To The No-Decompression Limits.
Perform Only No-Decompression Diving.
Do Not Exceed The Computer Specified Ascent Rate.
Make A Safety Stop at Approximately 5m/15ft For 3-5 Minutes During Ascent.

102. Summary of Dive Computer Guidelines
Make The Deepest Dive First.
Repetitive Dives In Excess Of 30m/100ft Should Be Avoided.
Do Not Turn The Computer Off Before Out Gassing Is Complete.
Know The Computer Failure Procedures.
Know The Flying After Diving Procedure.

103. A Final Note: Dive Wisely
Dive computers have given divers the freedom of multi-level diving.
This freedom allows us to spend more time exploring and enjoying the underwater world.
Remember that neither the dive tables nor a dive computer can absolutely insure that a diver will not get decompression sickness. These devices are based upon mathematical models that have been supported by experimentation and research.
Use them properly, following the manufacturer’s directions and the dive guidelines previously recommended. Using these devices properly and conservatively will greatly prevent the likelihood of injury from decompression sickness.

104. Advanced Topics
Nitrox
Decompression Diving

105. Nitrox Standard air roughly 21% O2 & 79% N2
Enriched Air Nitrox (EAN) has higher O2 and lower N2, e.g. 32%-68%
Lower N2 allows for longer bottom time, but…
Higher O2 limits how deep you can dive
The Gekko can be programmed for O2 up to 50%

106. Set Gekko to Nitrox Mode (SET > MODEL > NITROX)
O2% can be set to 21-50%
PO2 can be set to 1.2 to 1.6
MOD is calculated automatically
Click on video clip to start & stop

107. EXERCISE #5 Set to Nitrox Mode Set O2% to 36 Set PO2 to 1.5
What is the MOD?
ANSWER: 100 feet
Go to Plan Mode
What is the No Dec 100 feet?
ANSWER: 31 Minutes

108. Nitrox Dive Display O2% Display
When in Nitrox Mode, the O2 setting is always displayed.

109. Nitrox Dive Display Oxygen Limit Factor (OLF)
>100%
100%
Displays CNS or OTU, whichever is greater
Bottom segment flashes when controlled by OTU
10%

110. Nitrox Dive Display

111. Nitrox Dive Display: Alternate
Press Time Button for alternate display
Shows CBT and time of day
Stays on for 5 seconds

112. Nitrox Notes 21% is the default O2 setting
If set to 22% or higher and a dive IS NOT made within two hours, defaults back to 21%
If a dive is 22% or higher, Gekko retains setting until “clean”
Once a Nitrox dive is made, cannot switch back to Air Mode; must use 21% instead

113. Decompression Dive Mode
Occurs when No Dec Time becomes 0
Cannot ascend directly to surface
Must stop at “Ceiling” to decompress

114. Decompression Terms
Ceiling: The shallowest depth to which you can ascend
Ceiling Zone: From the ceiling to 6 ft below. Optimum decompression depth
Floor: Deepest depth at which deco time obligation does not increase
Decompression Range: Depth range between ceiling and floor. Decompression is slower near floor

115. Decompression Dive Mode
CBT completely full
Ceiling Depth replaces max depth
Up Arrow = Below the Floor. Start ascending immediately
Ascent Time replaces no-deco time. Ascent time = time to ascend from depth + time to decompress

116. Decompression Dive Mode
Above the floor
The up arrow disappears.
No longer adding to Ascent time
Still too deep for optimum decompression

117. Decompression Dive Mode
At the Ceiling Zone
Up and Down arrows are displayed.
Optimum decompression depth

118. To Learn More Or