Cochran Computers & Adaptive Algorithms

[Dive Cochran]

Cochran Undersea Technology designs, manufactures, and markets state-of-the-art diving computers for recreational, technical, CCR and commercial divers from our facility located in Richardson, TX. Cochran has been designing dive computers for itself and others for over twenty years. Cochran is the exclusive provider to the U.S. Navy and its dive computers are Approved for Military Use (“AMU”) listed and its dive computers are being used by other international Navies and have NATO part numbers. With that said please click on the link below "Enviromental Compensation"


http://www.divecochran.com/techpubs/Docs/EnvironmentalCompensation.pdf


Cochran Undersea Technology
sales@DiveCochran.com
salesmanager@DiveCochran.com


Come visit Cochran Undersea Technology at the DEMA SHOW 2014 in the Las Vegas Convention Center, Las Vegas, NV November 19-22, Booth 1351.

 

[Dive Cochran]

Cochran Undersea Technology designs, manufactures, and markets state-of-the-art diving computers for recreational, technical, CCR and commercial divers from our facility located in Richardson, TX. Cochran has been designing dive computers for itself and others for over twenty years. Cochran is the exclusive provider to the U.S. Navy and its dive computers are Approved for Military Use (“AMU&#8221 listed and its dive computers are being used by other international Navies and have NATO part numbers. With that said please read the following

Enviromental Compensation


Cochran Dive Computers are a new breed of dive computers that adapts its algorithm to the users diving environment and style as originally pioneered by Cochran. All of Cochran’s current dive computers incorporate this capability


Water Temperature


Diving in cold water can lead to a lower diver core and skin temperature which can affect the gas exchange rate of the body’s tissues. All Cochran dive computers feature two modes of Temperature Compensation, Normal or Reduced. The dive computer progressively makes its algorithms more conservative as the water temperature declines below 75 degrees F. Above this water temperature, there is no temperature compensation. In the Reduced Mode, the temperature compensation is made less conservative by approximately one-half the amount of the Normal Mode. If the diver is wearing an insulated dry suit and is relatively warm even in cold water, this temperature compensation factor may be set to Reduced Mode at the divers discretion using the Analyst® PC software.


Altitude


While many dive computers require the diver to manually set the altitude, Cochran products are fully automatic. Driving or flying to a dive site significantly higher in altitude requires special modifications to the "sea level" algorithm. All Cochran dive computers regularly sample the ambient barometric pressure to determine these changes in altitude whether the unit is On or Off. Accordingly, the algorithm is changed to reflect these barometric pressure changes. Note that temperature and weather systems also affect barometric pressure and hence, apparent altitude. Using the Time-To- Fly digits, the number of hours required to “adapt” to the new altitude is immediately known to the diver. If a significant altitude change occurs, a minimum of one hour should pass before diving to allow both the diver and the unit to adapt to this new altitude.


Microbubbles


There are several theories regarding the exact method by which an inert gas bubble forms from a microbubble which was formed from micronuclei. Currently the predominant theory states that in addition to other factors, more rapid ascents accelerate bubble formation. All Cochran dive computers comprehend and adjust for this phenomenon.


User Added Conservatism


Current dive computers cannot tell if the diver is dehydrated, tired, smokes, overweight, or has some other physical issue that may require additional conservatism in the algorithm. All Cochran dive computers allow the diver to input an added degree of conservatism to the algorithm from 0 to 50 percent in one-percent increments. This can be done via the Touch Contact Programming Mode or with the Analyst® Personal Computer Interface.


Previous Dive Profiles


One theory states that under some circumstances, recent dive activity can have an effect on inert gas loading, particularly if the diver engages in inverted profile diving. This occurs when a deep dive is followed by an even deeper dive. This recent dive history is used to compensate the inert gas loading for the current dive. This can be enabled or disabled with the Analyst® Personal Computer Interface. Current theories indicate that diving Inverted Profiles has no appreciable effect on Nitrogen loading. This compensation is turned off when the dive computer is shipped and must be turned on by the user.


Salt Water / Fresh Water


There is approximately a three percent difference in depth readings taken in salt water versus fresh water. Some dive computers are calibrated in feet of fresh water and some are calibrated in feet of seawater. Diving in a medium different from what the dive computer is calibrated will cause apparent depth errors. Only Cochran dive computers actually determine the type of diving medium and compensate the depth reading accordingly. This is accomplished by measuring the conductivity and capacitance of the water during a dive. Caution must be taken in interpreting this reading since some apparent fresh water is actually high in minerals or contaminants and is correctly compensated as salt water (High Conductivity, higher density). This commonly occurs in some caves, springs, and lakes.


Workload Compensation


This feature is available only on the Cochran Gemini dive computer which is Air Integrated. When a diver’s work rate or exertion level increases, he consumes more breathing gas and his Breathing Mix Gas Consumption (GC)/Surface Air Consumption (SAC) increases. The diver exchanges and retains higher levels of nitrogen in his tissues at a high work rate as compared to a low work rate. As work load increases, Cochran dive computers compensate by progressively increasing the conservatism of its algorithms. The Workload Compensation starts when the diver’s GC exceeds 35 psi per minute and reaches maximum compensation at 98 psi per minute. For accurate Workload Compensation the cylinder size, in liters, must be set correctly. This can be done via the Touch Contact Programming Mode or with the Analyst® Personal Computer Interface

 

[Dive Cochran]

Cochran Dive Computer Firsts

In a Dive Computer, Cochran is the first company to:

Ø develop and market a wireless (“hoseless&#8221 Air Integrated Dive Computer,
Ø implement the Navy VVAL-18 algorithm in a dive computer,
Ø attend annual NATO exercises,
Ø be listed on the US Navy Approved for Military Use (“AMU&#8221 list,
Ø be listed on the NATO purchase list,
Ø produce a Low Mu Explosive Ordnance Disposal (“EOD&#8221 unit,
Ø produce a RoHS compliant dive computer,
Ø have one-second dive profiling,
Ø have massive dive profiling memory,
Ø use tapping instead of pushbuttons to activate features,
Ø export high resolution profiles in .csv files,
Ø patent Hands-free gas switching,
Ø implement microbubble formation mitigation algorithm,
Ø implement diver’s automatic Workload compensation,
Ø implement diver’s water temperature compensation,
Ø implement diver’s Salt/Fresh Water compensation,
Ø implement user Programmable Conservatism,
Ø implement automatic altitude adaption/acclimatization,
Ø produce and market a user Programmable Nitrox Dive Computer,
Ø implement multiple diving gasses in a Dive Computer,
Ø host DAN Field Research Coordinator training course,
Ø implement a direct link to DAN’s secure FTP site for Logbook,
Ø implement Parametric Cloning of two Dive Computers,
Ø introduce a sophisticated PC Interface,
Ø include a Flight Data Recorder in a Dive Computer,
Ø be used in the US Navy’s first decompression computer dive,
Ø include a Flight Data Recorder in a Dive Computer.

Note: Red text indicates that Cochran is also the ONLY Dive Computer

 

[Dive Cochran]

Batteries: Disposable Vs. Rechargeable

Introduction ​

Mike Cochran has been designing and producing battery powered products for over four decades. His first were at Texas Instruments where he invented TI’s first Scientific Calculators. These early products were powered by rechargeable batteries because the power consumption was too high and hence, battery life too short for disposable batteries. These calculators used a Light Emitting Diode (LED) display which consumed energy and used a relatively high power processor. In the years since, the units were converted to a much lower power Liquid Crystal Display (LCD) and processor power consumption was reduced so the later units were designed with disposable batteries. Today, almost all Scientific Calculators are powered with disposable batteries that last for many years. This avoids all of the disadvantages of rechargeable systems.


In Richardson, Texas, Cochran Consulting designs and manufactures a number of uniquely different battery powered products. Some use rechargeable batteries and some use disposable batteries. Each battery type has its own advantages and disadvantages. This paper will focus on two of Cochran’s products (Thermal Imagers and Dive Computers) and why one uses disposable batteries and the other uses rechargeable batteries.
For this discussion, within the category of Rechargeable Batteries are two basic types, Permanent and Replaceable.
Cochran Thermal Imagers

Cochran Thermal Imagers (Cochran Fire & Security Products Division) are small hand-held or helmet-mounted devices used by individuals for viewing thermal energy in a variety of applications. The microbolometer used in the imager consumes substantial energy as does the 3D LED viewers.
The relatively large total amount of energy consumed makes disposable batteries not a good choice as significant battery weight would need to be added to power the unit for a reasonable period of time. Furthermore, the added batteries size would increase the physical size of the Imager too much.
Therefore, for the Cochran Imager the decision was made to use rechargeable batteries. Instead of standard Lithium-ion batteries, Lithium-ion Polymer batteries (LiPol) were chosen because of their high ratio of power-density to physical size and weight. Also, certain LiPol batteries are not toxic or flammable and do not explode.

Cochran Dive Computers ​

For over twenty years, Cochran has been designing dive computers for itself and others. In addition to recreational and commercial units, Cochran is the exclusive provider to the U.S. Navy and other international Navies including NATO. Cochran designs the products it produces and markets with a continuing effort focused on providing the diver with a reliable, cost-effective, and trouble-free, state-of-the-art product. Intense effort has been placed on reducing power consumption because the dive computers are battery powered and Cochran wants to give the diver very long battery life. Worrying about battery life should not be a factor while diving.
The choice of a display for a dive computer is the most critical factor when considering battery life. Organic Light Emitting Diode (OLED) displays have extremely high power requirements. LED displays that require a continuous backlight also have high power requirements. Typically, the relatively high power required of these displays forces some of those products into using rechargeable batteries regardless of the disadvantages. Transflective Liquid Crystal Displays with on-demand color backlight like those used in Cochran products have a near zero power requirement.

It is important to note that a new, fresh, Disposable Battery contains substantially more energy than a new, fresh rechargeable battery, assuming the same physical size. For the Cochran dive computers, transflective LCD Displays with disposable batteries continue to be the strategy.

Batteries ​

When using disposable batteries it is important to use only name-brand products that are known to be new or fresh. Only use Lithium-ion or Alkaline as the dive computer manufacturer recommends.
There are a number of issues with any rechargeable battery system that require careful and challenging considerations:
Exploding Batteries

As evidenced by a recent (March 2013) dive computer recall, some rechargeable batteries particularly the cylindrical type, can explode. One should take great care when using them.
Sudden Shutdown
Rechargeable batteries have an extremely sharp discharge curve when reaching the end of its charge. This can result in an unexpected and sudden shutdown of your dive computer. There have been numerous reports of this occurring and unfortunately, on live-aboard dive trips it can be very expensive and frustrating. Should this occur, some dive computers require the diver to stay out of the water for 48 hours.
Because of the typically very long life of disposable battery dive systems (like Cochran) multiple low battery warnings are issued long before any shutdown.
Finite Recharge Half-life

From the very first time a rechargeable battery is charged it begins to age a little with every recharge. Typically, the half-life of a rechargeable battery is 300 recharges. For example, if a new battery lasts 5 hours on a recharge, after it has been recharged 300 times it will last only 2.5 hours. (Those of us with cell phones have experienced this problem.) However, continuing research indicates this half-life will continue to be increased.
Disposable batteries like those in Cochran products do not have this issue.
User Replaceable
The Finite Half-life problem implies that rechargeable batteries should be user replaceable. Sending a product back to the factory or service center to have its batteries replaced is simply unacceptable. Cochran solved this problem in its Imagers by supplying an independent battery pack that is easily user replaceable. Cochran Imagers also come with two batteries. This way, the Imager can be continuously used by successively connecting freshly charged batteries.
All of Cochran dive products have user replaceable long-life batteries.
Rechargeable Battery: Unpredictable Remaining Charge
As a rechargeable battery inexorably ages, the time it will last between charges becomes unpredictable. Temperature also plays a role in the unpredictability. Furthermore, some display systems that modulate the brightness based on ambient light also contribute to unpredictability.
Disposable batteries can also have an unpredictable life. However, systems using them are typically extremely low power and battery life is typically very long. All of Cochran dive products have battery life typically over two years.
Self-discharge Rate
As soon as the charger is removed from a system the batteries begin to discharge on their own. This rate of self-discharge depends on the battery and its temperature. While this rate is typically small, it can be significant in low power systems such as a dive computer.
Disposable batteries like those in Cochran dive products do not have this issue.
Zero-charge Life

Permanent damage can occur any time a rechargeable battery is discharged to zero. Sophisticated systems like the Cochran Imagers do not allow the batteries to be discharged below 20%.
Disposable batteries like those in Cochran dive products do not have this issue.
Over-charge Life
In simpler systems, serious, permanent damage can occur any time a rechargeable is allowed to remain on the charger for extended periods of time. Sophisticated systems like the Cochran Imagers monitor the state of charge and cut off the charging system when the batteries are fully charged.
Disposable batteries like those in Cochran dive products do not have this issue.

Long-term Storage Life
A rechargeable battery half-life can be shortened by leaving it fully charged or discharged for long-term storage. Cochran Imagers are shipped at the optimum 80% of charge. Cochran recommends that prior to storage, to fully charge the battery and then discharge it by around 20%.
Disposable batteries like those in Cochran products do not have this issue.
Degradation
One source states: “Lithium ion batteries start to degrade from the moment they are made, and, in fact, will become inoperable after two to three years even if they aren't used.”

High Initial Parts Cost
Typically, rechargeable systems cost more than systems with disposable batteries. The more comprehensive battery management cost in properly designed systems coupled with the battery cost itself and its charging system cost are the main factors.
Replacement Battery and Related Cost
The battery cost per dive is small whether disposable or rechargeable batteries are used. The most significant battery cost factor is not the cost of the battery, but the cost of replacing a rechargeable battery at the factory.
Bulky Charger and Cable
Rechargeable systems require always having the charger available. They are prone to be lost or damaged which may leave the product unusable. Finding adequate power to recharge a system can be problematic while travelling or on a boat.
Relative Reliability
A poorly designed system is usually less reliable than a properly designed system. However, all things being equal, rechargeable systems can be less reliable than systems with disposable batteries because of the increased complexity and increased number of components including the charging system.
Battery Fuel Gauge, Coulomb Counter, and Warnings
Some products claim to have “Battery Fuel Gauge” while in fact, they do not. Assume:
• that the gas tank in your car got a little smaller with every fill-up,
• the temperature affected the size of the gas tank,
• your gas consumption changed with temperature,
• your gas consumption changed with your driving style.

Then a Gas Gauge that indicates a half full tank will not always give you the same driving time.

To be useful, a true Battery Gas Gauge MUST consider all of these factors. The Gas Gauge in Cochran’s imagers is also called a Coulomb Counter and accurately tells the user how much time in hours and minutes are remaining while considering ALL of the above factors.
In addition to a battery voltage reading, Cochran Dive Computers have an audible and visual warning when the battery is low and changing it is recommended. Furthermore, because of their very long battery life, Cochran units will give the diver adequate warnings to finish a dive and then change the battery. If the battery becomes too low during a dive the backlight cannot be turned on, thereby conserving battery energy. The diver can then use his dive light if necessary to see the display. When the unit is turned on, if inadequate battery life exists for several dives, the unit will turn back off.
Planned Obsolescence
“With today’s technology, when a product is designed with rechargeable batteries, it is a fact that the product will eventually become unusable due to the limited lifetime of the batteries. The only acceptable solution is to allow the user to replace the batteries when the life becomes too short. Permanent, rechargeable batteries are simply unacceptable to us.”

“On a rechargeable system with a user replaceable battery, if the battery life is too short then the diver may need to carry a number of spare batteries to last a full week of diving on a live-aboard. The risk of not being able to conveniently and quickly recharge batteries and losing days diving is simply unacceptable to us.”

 

[Dive Cochran]

Batteries: Caveat Emptor

Prior to purchasing a dive computer it is important to understand the ramifications of its battery power system. Did you know that some products:
Ø require expensive, hard to find batteries?
Ø are being recalled for exploding batteries? (March 2013)
Ø must be returned to the factory every two years to get the batteries replaced?
Ø can suddenly lose power and tell you stay out of the water for 48 hours?
Ø need to be recharged every five hours of diving?
Ø have user replaceable batteries but if you replace them the warranty is voided?
Ø say to stay out of the water for 48 hours when you replace the batteries?
Ø require special tools to replace the batteries?
Ø void the warranty if you do not buy new batteries from them?
Ø lose all nitrogen loading when the batteries are replaced?
Ø require sending to the factory to have rechargeable batteries replaced?

Cochran’s goal is to allow Cochran dive computer owners to maximize their diving experience without undue concern of a battery failure. All Cochran dive computers are designed for extremely low power consumption and therefore, have the longest battery life. All Cochran dive computers have user replaceable batteries that do not require special tools and can be purchased from a number of sources, or available from Cochran.

Cochran EMC-14 ​

The EMC-14 is Cochran’s lowest cost dive computer and is powered by two standard Alkaline “N” cells. Batteries can be easily replaced by the user with no tools. With quality, fresh batteries, battery life is typically over 500 dive hours. For recreational use it is recommended to replace the batteries every 500 dive hours or two years, whichever occurs first. For high use applications more frequent changes may be necessary.

Cochran EMC-16


The EMC-16 is Cochran’s low cost, yet powerful dive computer and is powered by one 3 volt Lithium disposable battery available from a number of sources. Although not recommended, the unit can be powered by two standard alkaline “N” cells but with shortened battery life. The battery can be easily
replaced by the user with no tools. With a quality, fresh Lithium battery, battery life is over 500 dive hours. For recreational use it is recommended to replace the battery every 500 dive hours or two years, whichever occurs first. For high use applications more frequent changes may be necessary.
Product battery life assumes typical use of the Taclite using the default setting.

Cochran EMC-20H ​

The EMC-20H is Cochran’s most powerful wrist-worn dive computer and is powered by one 3 volt Lithium disposable battery available from a number of sources. Although not recommended, the unit can be powered by two standard alkaline “N” cells but with shortened battery life. The battery can be easily replaced by the user with no tools. With a quality, fresh Lithium battery, battery life is over 500 dive hours. For recreational use it is recommended to replace the batteries every 500 dive hours or two years, whichever occurs first. For high use applications more frequent changes may be necessary.
Product battery life assumes typical use of the Taclite using the default setting.

Cochran Gemini Hoseless ​

The Gemini is Cochran’s Hoseless Gas Integrated dive computer. The cylinder mounted computer/transmitter is powered by four standard Alkaline “AA” cells. There are two battery compartments each with two “AA” batteries. The compartments are redundant such that both independently power the unit. The Wrist worn unit is powered by a pair of user replaceable “N” cells. Batteries can be easily replaced by the user with no tools. With quality, fresh batteries, the Cylinder Unit battery life is typically over 500 dive hours or two years, whichever occurs first. With quality, fresh batteries, the Wrist worn battery life is typically over 500 dive hours or two years, whichever occurs first. For high use applications such as commercial, instructors, or military, annual replacement is recommended.
Wrist worn unit battery life assumes typical use of the Taclite using the default setting.

---------- Post added July 9th, 2014 at 02:46 PM ----------




Task Loading

While scuba diving, the diver wants to focus on his Mission whether it be cruising a reef, photographing fish, cave diving, disarming a mine, or just diving with a buddy for the fun of it. The diver doesn’t need or want to be distracted or concerned by equipment tasks that could be easily avoided. Cochran dive computers have the lowest task loading of any unit on the market today. This is one reason why Cochran is the only dive computer used by NATO, the US Navy, and other international militaries. Cochran’s goal is to allow Cochran dive computer owners to maximize their diving experience. Toward this goal, Cochran has addressed the following issues:

No Buttons – no Worries ​

Regardless of how well a product is designed, having pushbuttons is always less reliable than not having pushbuttons. Pushbuttons can be troublesome when wearing gloves. Trying to press a pushbutton or combination of pushbuttons while carrying a camera and taking a picture is at best, challenging. Cochran dive computers are fully automatic and have no pushbuttons. If desired to change any settings in a Cochran dive computer while on the surface, the diver uses the three permanent stainless contacts on the side or bottom of the unit.

Batteries ​

Cochran dive computers have the longest battery life. By checking for battery warnings just before a dive, the diver can be assured that when he starts a dive there is sufficient battery power to complete it. Constantly checking the battery while in a dive is not necessary with a Cochran dive computer.

Hands-free Gas Switching ​

Cochran invented and patented (US 5,794,616) automatic gas switching and refers to it as “Hands-free Gas Switching”. For air integrated units like the Cochran Gemini switches are based on gas flow and depth and time. For other Cochran units, switches are based of depth and time. Sophisticated firmware within the Cochran dive computers manages the gas switching so the diver doesn’t need to.

Missed Deco Stops ​

With Cochran dive computers the diver does not need to be concerned about it shutting off or stopping to compute decompression. The diver no longer must focus exclusively on the depth to prevent straying into a zone that causes the unit to stop.

During decompression dives while ascending it is important to precisely follow the ceiling recommendations of the dive computer. Realistically, this is extraordinarily difficult. If the diver is at or deeper than the recommended ceiling, Cochran dive computers continue to properly compute gas residuals based on the diver’s current depth. If the diver is shallower than the recommended ceiling, Cochran dive computers continue to properly compute gas residuals based on the diver’s current depth. However, as long as the diver is too shallow, the dive computer will issue a unique audible alarm every second. If the diver stays too shallow, eventually that ceiling will be satisfied. Cochran dive computers never shut down or leave the diver hanging.

Audible Warnings

Cochran dive computers are the only ones that have different audible warnings to indicate to the diver a warning condition exists. With experience the diver can identify a specific warning based on this sound without looking at the display. The seven different warning tones can be seen below. All tones are issued once per second. The ascent rate warning is issued every second the diver is ascending too fast. The Ceiling-depth warning is issued every second the diver is shallower than the Ceiling. Other warnings are issued once per second for five seconds and then repeated for as long as the warning condition exists.

Ø General Purpose Alarm Long Beep 1000hz tone for 300ms
Ø Altitude/Firmware/RAM/ Error Short Beep 1000hz tone for 100ms
Ø Depth is less than ceiling Up Sweep rising tone for 300ms
Ø Ascent Rate too fast Down Sweep falling tone for 300ms
Ø CNS, OTU, High/Low PO2 Double Chirp 1000hz & ,500hz for 300ms
Ø Sensor Failure Two Tone Beep 1000hz,1000hz for 300ms
Ø Low/Bad Battery Low Tone 333hz for 300ms

---------- Post added July 9th, 2014 at 02:55 PM ----------


Stealthy Diving

Diving stealthy is a broad subject and this Tech Pub will focus only on Stealthy Dive Computers. Cochran is the exclusive provider of dive computers to the U.S. Navy and other international militaries. A number of different models are available for a range of applications from covert SEAL missions to Explosive Ordnance Disposal (EOD) units. Discussed here are some of the dive computer attributes seen in those units.

Magnetic Signature ​

For EOD applications it is critical that the equipment used by the diver have an extremely low magnetic signature to prevent setting off a magnetic mine. After a very challenging design and careful monitoring of production, Cochran supplies the required product to world-wide militaries. Its magnetic signature is extraordinarily low, far below the Military requirement.

EMF Emissions

Typically, dive computers that consume a relatively high power may also emit significant EMF energy that can be detected by sensitive instruments. Furthermore, pixilated displays that have high power and fast scan rates can also have relatively higher EMF emissions. Cochran displays are not pixilated and use very low power with very low scan rates.

Audible Emissions ​

During underwater covert missions it is critical to avoid any sounds that could be picked up by hydrophones. These sounds could be caused by the dive computers audible warnings or mechanical noise caused by the dive computers attachment to the diver. The Cochran dive computers audible warning can be disabled via the Military Master version of the Analyst^® PC software. Products are also designed to eliminate any noise created by the mounting hardware.

Visible Light Emissions

On a covert underwater mission, using a dive computer that has an illuminated display that can be seen from the surface or by another diver can be deadly. This can be a significant issue if using a dive computer with an OLED display or LED display that emits light over a wide spectrum typical of color displays. Red light does not propagate well underwater. All Cochran dive computers use a transflective segmented LCD display that reflects most of the ambient light such that it usually can be seen without any artificial or emitted light. Cochran units have an on-demand Red backlight for use in
very dark ambient light conditions. The backlight is turned on by thediver by tapping on the dive computer.The Red backlight stays on for ten seconds then automatically turns off.This ten second period can be changed via the Analyst^®PC software.

---------- Post added July 9th, 2014 at 03:00 PM ----------

“Not just another pretty face * Cochran * designed for use, not fashion”