Hello mokap,
Thank you for your question.
I found an excellent article for you on diving computer history:
http://www.mtsinai.org/pulmonary/books/scuba/sectionj.htm
SCUBA DIVING EXPLAINED
Questions and Answers on
Physiology and Medical Aspects of Scuba Diving
Lawrence Martin, M.D. Copyright 1997
Dive Tables and Dive Computers: Their History and Utility
"...WHAT IS THE ORIGIN OF DIVE COMPUTERS?
Until the early 1980s almost all recreational diving was taught by the
standards of U.S. Navy tables. Because the Navy tables are not based
on multi-level diving profiles, scientists developed algorithms that
take into account changes in nitrogen uptake with continuous changes
in depth. These algorithms were mainly theoretical models until the
microchip revolution made them accessible and workable in a hand-held
computer. When the algorithm is programmed into a computer that also
senses depth (a simple depth gauge) and measures time, you have a
"dive computer."
The first commercially available dive computer was the Orca Edge, in
1983. Since then dive computers have become smaller and more
versatile. They are now manufactured by many companies, and
incorporate one of several algorithms for calculating nitrogen uptake
and elimination.
WHAT DO DIVE COMPUTERS DO?
Based on the algorithm used, the dive computer (Figure 5) tracks depth
and time every second or so; with this information it continuously
computes nitrogen uptake and elimination in the various theoretical
compartments assumed by the algorithm. (Among the various computer
models the number of compartments ranges from about 6 to 16). Using
measurements of depth and time at depth, the computer calculates the
nitrogen saturation and de-saturation of each compartment, and rapidly
converts this information into a digital readout for the diver.
Keeping track of multi-level diving is no problem for the computer. At
the same time the computer performs other functions, such as tracking
rate of ascent. Not all dive computers function alike, but most are
able to provide the following information:
during the dive
-depth
-number of the dive (first, second, etc.)
-time elapsed since dive began
-how many minutes may be spent at current depth before a decompression
stop becomes mandatory
speed of ascent, and some type of message flashed if it is too fast
-water temperature
after the dive
-maximum depth reached
-length of time that can be spent at various depths on the next dive
-when it will be safe to fly (time to desaturation)
Dive computers are constantly evolving, and many on the market offer
additional features, such as air integration for registering tank
pressure(replacing the stand alone air gauge), information about how
long air will last at the diver's current rate of breathing, various
log or bookkeeping functions, and algorithms for nitrox and perhaps
other types of mixed gas diving. Regardless of what features a dive
computer has, none can account for individual diver characteristics
such as age, weight, percent of body fat and degree of physical
conditioning. Although a computer could be designed to accept this
type of information, the existing algorithms (like all
commercially-available tables) are population-based; they are not
designed specifically for the person who buys and uses the computer.
(Professional and technical divers sometimes use customized tables, a
practice not yet feasible for recreational divers.)
...HOW ACCURATE ARE DIVE COMPUTERS?
This is a subject of much debate in the dive community. The real
question is, "If I use the computer properly, will it to keep me from
getting the bends?" Obviously, the computer computes accurately; but
is the algorithm on which it is based sufficient to prevent the bends?
The answer is both "yes" and "no."
No, because some divers using computers properly have developed DCS;
documented cases are reported to Divers Alert Network every year. The
reason(s) are unknown, but most likely have to do with individual
susceptibility and diving at or close to the computer's limits. There
is significant variation among computers in the times allowed at
various depths (because the algorithms differ), but too little is
known about this variation to blame any particular algorithm for a DCS
problem. There is surprisingly little published information about the
various computer algorithms in terms of actual testing; however, there
is also no evidence that any particular algorithm is "dangerous" or
"unsafe." (If there is, I am unaware of it).
The answer is also "yes" because the vast majority of divers who
follow their computer do not develop the bends, even though their
profiles may exceed what would be allowed with square-wave-based dive
tables. In one respect, at least, computer algorithms have been more
conservative than tables -- in their allowed rate of ascent. Dive
computers have long allowed for an ascent rate much slower than the
training agencies' old recommendation of 60 ft./minute. (Training
agencies now recommend an ascent rate no faster than 30 feet/minute).
Some computers allow for different rates of ascent, faster at deeper
depths, then slower at shallower depths. A typical allowed rate of
ascent above 60 fsw is 30 to 35 feet/minute; if the diver is rising
faster than this rate the computer will flash SLOW or provide an
audible signal to the diver.
In summary, a modern dive computer, used wisely, is accurate - but not
infallible..."
Although this is an older article and some of the graphics are no
longer linked, I think you will find the entire article informative
and interesting.
SanDiegoDiving.com has a number of links to dive computers:
http://www.sandiegodiving.com/resources/links/diveComputers/
For example, Aeris:
http://www.diveaeris.com/
You will be able to glean a lot of information from browsing the
manufacturer's sites listed here and learning about current production
models.
You also might enjoy this article:
http://www.skin-diver.com/departments/gearingup/accessories/may00_computer.asp?theID=1212
"2000-05 Dive Computer Evolution
By Daryl Carson
When you ask divers about their certification class, no one ever gets
excited and says, “Oh, oh, and learning those dive tables was so much
fun!” Diving itself is quite fun, yes, but calculating dive tables,
tracking repetitive dives, pressure groups and accumulated bottom time
has about the same thrill factor as a conversation with your
father-in-law. The one that sells life insurance. To old people.
This dislike for dive table calculations is one of the great
traditions of diving, much like peeing in your wetsuit to stay warm.
In fact, since the very first days of scuba, divers have been building
machines to do the calculations for them. As early as the 1950s there
were “decompression meters,” “decompression computers,” “deco-meters”
and a slew of other devices that have evolved into the present day
“dive computer.” Following is a look back at these magnificent devices
and the innovations that we often take for granted..."
Search Strategy:
history of diving computers
I trust my research has provided the history of dive computers you
desired as well as a peek into future products. If a link above should
fail to work or anything require further explanation or research,
please do post a Request for Clarification prior to rating the answer
and closing the question and I will be pleased to assist further.
Regards,
-=clouseau=- |
