Uemis ZURICH SDA (Scuba Diver Assistant); a dive computer and a village — EDITOR’S CHOICE AWARD

How about a dive computer that is nearly bright enough to be a secondary dive light? How about a dive computer that also displays your buddy’s air? How about a dive computer is a real computer and comes with FREE software and updates? Then, for good measure, throw in a worldwide social network of divers and dealers that feed you and your computer dive site details and more. These are only a few tidbits of information that hint at what you get with the uemis ZURICH and why it leads the new category of SDA (Scuba Diver Assistant) devices.

UEMIS: the company’s “acro-name” stands for Underwater Equipment Made in Switzerland. SDA (Scuba Diver Assistant) is used to describe this instrument because as Ernst Voellm, the Uemis CTO says, “it’s not only a dive computer.” The SDA moniker is not just marketing hype, like a PDA (personal digital assistant), this SDA has uses above and below the water.

“… my buddy could easily read my remaining air from 15 feet away.”

In an April 2009 ScubaGadget article WAIT, Don’t Buy a New Dive Computer, we predicted that big bright OLED screens were on the way (OLED – an acronym for organic light emitting diodes = do not require a backlight to function). While companies still continue to churn out DOS era monochrome LCD screens and divers still buy them, OLEDs are here. There is no longer a reason to squint to see your dive stats. The UEMIS color OLED screen is so bright it overcomes my need to use my gauge readers. On my early test dives, I missed some of the undersea life because I was enthralled with watching my SDA. The brilliance of the OLED is also as grand in bright sun as it is in darkness. The point does beg to be bluntly repeated: we cannot understand both why manufacturers would still build antiquated LCD dive computers and, even more, why divers would, when given the choice, still buy them.

OLED displays have two more great characteristics, a deep black background and they only use around 50% the power of a color LCD. UEMIS makes good use of the brilliant colors employing an easy to grasp “traffic light logic” for indicating the urgency of the message. Green means you are fine, orange means caution, and red is a warning.

I was recently diving with a new dive buddy. About half-way through the dive, he flashed me the fives to indicate his approximate remaining air pressure. In reply, I just stuck out my arm. Even in our limited Northwest viz, he could easily read my remaining air from 15 feet away on my UEMIS. Remaining air communication is even easier if your buddies are also wearing a UEMIS. Because the UEMIS is a hose-less computer with receiving and transmitting capabilities, you can tune into and read their remaining air directly on your screen. The tank pressure transmitter has a user-replaceable CR2 lithium battery. If you have multiple mixes, you can use up to three transmitters to monitor each of them.

a bit more about hose-less air integrated (AI) computers

In addition to super-cool features, like being able to check your buddies gas from your UEMIS SDA, AI computers including the UEMIS provide valuable life protecting features. These include the ability to calculate remaining air and bottom time by monitoring air consumption. Even more importantly, they can modify the decompression schedule according to your workload. Your computer can detect if you are breathing heavily at depth, account for the additional nitrogen loading, and adapt by altering your no-decompression limits or adding extra decompression or safety stop time. Getting all of this without a cumbersome hose attached multiplies the convenience factor.

But are they reliable? Triggered by viral stories of transmitter problems with first generation of other (not UEMIS) hose-less air integrated dive computers, some divers are still hesitant about going hose-less. Even though the technology has greatly advanced and failures are now very rare, other “schools” claim the transmitter as just another “point of failure.” Those in the “hose only” camp do not seem to be taking into account that all hoses will also fail at some point. If we are talking disasters, we could include another point here. When the hose connected to your computer fails, it is a true emergency because you are quickly losing tank gas. If a wireless transmitter fails to transmit, it should be only an inconvenience because you will presumably still have gas to breath while you switch to your backup.

I discovered one other fact that leads me to put a bit more trust in UEMIS than other hose-less computers. Designer Ernst Voellm is a well recognized pioneer and expert in this field. He is co-inventor for a patent on the technology that transmits the pressure from your tires to you auto’s computer.

In any case, more and more smart divers are adding an inexpensive SPG (submersible pressure gauge) to their regulator to backup both hose connected and hose-less AI dive computers. To answer a question I had, if you have only one HP port, splitters are available.

Easy to use

Very few people enjoy reading instructions. One of the top indicators of any well designed user interface (UI) is that users can get around without first reading the manual. For the most part, the UEMIS SDA is intuitive and we were able to find and use most features before we read the manual. While there is a room for improvement, this a significant improvement over most other dive computers. With another brand dive computer which we owned for years, we always had to dig for the manual. The old round LCD dive computers mostly need to use confusing abbreviated menus to save space on the screen. The three magnetic slide switches and full-word menus of the UEMIS are a great help.

For entering text directly directly into the SDA (not the only option), you use a full display virtual keyboard that sometimes requires a lot of switch clicking. Bill Stone, another reviewer and UEMIS sales rep, suggests a rolling wheel style entry may be more efficient. This is a dilemma that all non-mouse, non-touch screen interfaces must deal with. Neither options are great, but UEMIS offers two easier alternative methods. You can enter information into the web application and then sync with your SDA. Or, even more simple, you can find your dive site information on the UEMIS online network (uemis DiveWorld (www.uemis.org)) and just download the complete record into your SDA.

The included water resistant manual is complete and fairly easy to follow. Online, searchable PDF versions are also available.

During the dive

While the UEMIS SDA seems to offer as much information during a dive as an airplane instrument panel, it is well placed and we never felt overwhelmed by the data. Again, for the most part, the over 30 bits of data, warnings or cautions are quite easy to find and understand; we have seldom had to check with the manual.

I tended to use the digital display, but the SDA also offers a larger remaining air display with tank pressure shown in both numbers and a graphic of a gauge with green, orange and red sections. Other graphic display extras include current gas consumption, physiological graphs (workload, skin cooling and microbubbles), tissue saturation and more.

Post dive

Post dive information is much richer than other computers. On the main screen, color changed dots and a countdown time give you clear indicators when it is/will be safe-time-to-fly and when you will be totally totally de-saturated of excess nitrogen. But the Zurich’s Swiss heritage truly is revealed by the prominent mountain image with an included altitude counter the reveals you current maximum safe altitude for the drive home over that high altitude pass.

In addition this SDA contains a full and detailed 2000 hour logbook that is searchable by an on screen calendar view (and also viewable with the application on the web on your pc or the web). Just a few of the advanced features available include: auto buddy entry (for other UEMIS divers), your dive profile displayed in color code graphic or numerical form which you can replay in 5 second increments and rich selection of depth and decompression histograms.


If you need an alert or just a pre-set reminder, the UEMIS practically tugs on your arm. The alerts and warning screens are even brighter and bolder and are accompanied by a loud audible signal. Ascend a bit too fast and you will see the screen filling giant arrow and bold warning to SLOW DOWN. We particularly loved the clear deco/safety-stop indication. As you approach a required or pre-set stop, two broad horizontal bars move slowly together and sync up when you reach the target depth.

It comes in colors (and sizes)

Worldwide, divers are becoming more fashion conscious. UEMIS has covered this base also, not only is the SDA well styled, it comes with the option to choose and even change between six different easy to change colored covers. These currently include red, blue, pink, yellow, black, or grey. The SDA also has the one best wristband designs we have seen. With a combination of an elastic section and a quick release, we had no trouble using with bulky dry or wet gloves. If that were not enough, the band is also available three sizes; small (232mm, 9.1 inch), medium (330mm, 12.9 inch), or large (410mm, 16.1 inch).

Beyond fashion, the color covers also hide at least two other convenience features. First is identification. We have a lot of duplicate equipment in our house and are always looking at tags and numbers to tell them apart. With the UEMIS we just grab our personal color and go. Additionally, removing the cover, with a small screwdriver (included, of course) allows you to both clean the computer and makes it much less expensive to replace if you damage the cover. The cover also contains the magnetic slide switches. With replacement covers at prices as low as $34 you can have a few to fit your fashion mood.

As a side note, we found that soaking our SDA’s in fresh water for a day after a dive kept them freely moving and prevented salt crystals jamming the magnetic slide switches.

Solar trickle charger

Another feature that draws the eye of other divers is the solar panel that sits above the display screen. UEMIS is the only scuba computer to integrate a solar panel. It is not designed to be a primary recharger to the Zurich’s lithium-polymer battery but it will keep the battery running a lot longer between charges. With the included standard USB cable charger, it is simple to find a place to recharge. With all of this talk of charging, we also want to add that even without charging (and the units sitting in the dark), the batteries do last a long time (Rated at 10 hours of diving). This is true even with the units at full brightness, which is not at all necessary with these super-bright screens.

The SDA has an inertial switch so it will turn on when you shake it. We did notice that one of our demo units was much more sensitive and would turn on by itself much more frequently. If there was a way to lock the unit off, it could extend this already long battery life.

SDA – much more than just a dive computer

UEMIS is clearly a customer centric company and demonstrates this by providing features and accessories for which others charge extra. Many other dive computes have the “ability” to connect to a proprietary dive log program on your home computer. Many of those charge extra for the software and/or the special cable to make that happen. We paid nearly $100 dollars to SUUNTO for a PC interface cable for our Cobra computers. While PC software updates are included, it is rare that you can update the firmware of the computer itself to add new features.

UEMIS has left this old “nickle and dime – limited features” model as far in the dust as the it technological distance between mono-LCD and OLED screens. UEMIS doesn’t just provide the cable, that cable is a standard USB cable. The snap on connector is included and makes a reliable connection simple. The software that connects the SDA to the web application on both PC and MAC is not only provided, UEMIS has built it into the SDA. I found I can grab any computer, plug the SDA into the USB port and interface; all while also charging the SDA to boot (more about that later). Every time I connect to a computer, I can also check for and download the latest firmware updates, FOR FREE!

But UEMIS is just getting started when they allow you to connect to a computer. When you interface, you are also connected to the UEMIS social network. Here you can look up dive sites, dive shops and charters, dive related businesses, and connect with other UEMIS members. Dive sites, often include, full descriptions and cautions, and include GPS coordinates mapped on the sites integrated map. If another diver has loaded a dive site that you are going to dive or have already dived, you can just download it into your SDA. This is especially great for dive vacations. You can download all of the dives sites into the SDA’s site database and have them ready for the picking into your logbook with a few clicks. We have not even yet discovered all of the advantages of the UEMIS network connection.

The Zurich uses a specially adapted version of the Buhlmann ZH-L8 algorithm which takes into account micro bubble formation, water temperature, repetitive dives, and workload, through gas-consumption information. It can be set for 5 safety levels and one or two minute deep stops. Nitrox range is adjustable between 21 and 100% O2. We often found on a very slow ascent that we only had a minute left on our safety stop by the time we hit our pre-assigned depth.

Even the strap is remarkable

The strap has multiple design features that make it secure and easy to use, even with bulky dry gloves. UEMIS designers have given the strap elasticity without compromising security. Rather than attaching a separate elastic section inline and risk failure, they pleated a section of the wide nylon webbing added elastic as over that, without a break in the webbing. For tightening there is an easy flow cinch clip the can be locked or unlocked with bulky gloves. Add just for good measure, you can even detach the strap at one end all together with a little flick of a hinged retainer. I am in awe of creative thought that went into this.

There is always a room for improvement

As with all computers, after the Kool-Aid wears off, you can always find room for improvement. Luckily, one of the great aspects of the UEMIS Zurich PDA ecosystem is most of desired updates are feasible. Better yet, so far, all updates have been free. One of the most called for updates, TriMix and CCR integration are already on the way. UEMIS is being very cautious, not releasing these important life saving features before they are fully confirmed as safe.

Our only real complaint, is not about the SDA, but centers around UEMIS DiveWorld online network interface. But before ranting a bit, I must add the caveat that, just having the DiveWorld online is so far advanced beyond any other dive computer that it hard to be anything less than thrilled, just to have this convenient feature. Being web applications designers we have seen and evaluated a lot of different interfaces. Without searching, reading the manual and and lots of practice, the web application interface is very confusing. Difficult to grasp and remember how to navigate through process of entering a new dive site online, downloading it and and syncing it with your SDA. It is not terrible, but could be a lot easier. There may be no way to say this without sounding provincial. But we found that the unique and wonderful design esthetic found in the SDA has become a detriment to the web application interface. The Flash based web interface designer has chosen the form over function. Not an uncommon issue with flash based sites. They are great for brochure sites, especially in the arts. But this web application it is not at all intuitive and really needs to be rebuilt with much less emphasis on looking good and all the focus on ease of use. Additionally, with Steve Jobs refusal to include Flash support on iPhones and iPads, this design essentially blocks out that whole segment of users.

The design of the SDA, that fact that you wear it on your arm, and the toughness of the crystal glass screen all make easy to keep it in good shape. However, we did find a few screen scratches on our demo, which are only noticeable on the surface and do not effect visibility of the unit out of the water. However, we had the idea, that with a smart phone screen protector and keep it perfect. The rectangular screen and removable cover would make it simple fit one of the cut-to-fit versions easy to install. We contacted Skinomi, makers of, in our opinion, the best and toughest screen protector, and they agreed to send us a few samples cut to fit the UEMIS. We will let you know how it works.


When we choose a product as editors choice it means a great deal. This award means that we liked this product so much, that if offered any dive computer available regardless of price we would choose the UEMIS Zurich SDA without hesitation. In fact, after the first few dives with demo units, we immediately made the decision to buy a pair of them for our personal use. For ScubaGadget, “editor’s choice” awards are only given to products which raise the bar and set a high standard for quality and innovation. We rate them as these products as the best choice in there category at any price.

We thank the amazing videographer and underwater explorer Laura James for introducing us to this product. Also, we greatly appreciate Aaron “Wally” Cummings and Joshua Hill of Tacoma Scuba for their invaluable help with background information.

As always, to comment on this and any other ScuabGadget articles, visit our FaceBook page at http://www.facebook.com/ScubaGadget