Appendix to Xiaomi MiJia Mini Review: The Case Of An Underwater Case

I got me a protective case for Xiaomi MiJia Mini, and it looks fine. If you decide to buy, you will find it is also incredibly cheap, especially on e-Bay where I got mine.

Sleek and transparent acryllic encasement is simple, since the camera itself only has one button which can do On-Off and Start-Stop. All else is accessible via its touchscreen…

… that can’t be accessed, once the camera is enclosed in the protective case! So do you have to stick to your recording plan that you set up prior to taking your cam under the surface? If you later wanted to change something, do you have to reach some place where you can dry the casing, open it, and use the touchscreen?

Simplicity is a good thing… Generally true, but not always, I thought.

And then I played around in the menu called “In Housing Mode” just to find out that you can yet use that single command button for other things. Namely, in that setting, long-press will open the list of other options, such as Video, Timelapse, Photo, Photo Timelapse, etc., and you can loop through those options using short-press command.  Of course, any special setting within any of the options mentioned should have been set up before (e.g. timelapse intervals, or photo ISO value, etc.) but then the changes, though limited to certain point, are still possible. The last option in “In Housing Mode” is Off, thus replacing the general function of long-press when the cam is not encased.

This is one of the most comprehensible use of one single-button command I have seen yet. Good thinking, Xiaomi!

As you can see in the above photo, the casing’s command button is too small – on a pin that is too long. It rages out of its leading well, which should actually ensure a wobble-free, straight-down linear movement. So, either the button pin is too long – or the well is too shallow! This is risky, as the pressing upon this button in a not exactly vertical move might upset the o-ring in its seat, enough to squirt water over the camera.

Aside from that, my main beef is about the bewilderingly constant wrong technology that the manufacturers use with the main hatch (“door”) sealing in a watertight case. Mainly it is directly related to the sealing principle, since they apply a wedge gasket, versus an infinitely safer o-ring. But the seal on this case that I got for Xiaomi MiJia Mini is the worst version by far, even compared to some other wedge-type sealings.

Links may show you more about underwater case maintenance and various seal systems.

Let me explain. It may be a lengthy read, but it just could spare you some costly frustration.

All underwater Action Camera casings I have seen use plastic latches & locks on the (usually) upper side of the case, and a simple hinge on the other. The plastic latch is supposed to keep the main hatch closed – so as to keep the sealing gasket around the hatch in its place.

The latch, supported by its oval wire spring, shouldn’t do anything else but keep the hatch in its closed position. The sealing gasket wedged between its groove and the inner rim of the case opening should sit safely in there, keeping the water out solely by its presence – and definitely not by depending upon some spring force.

Not with the case at hand, so to say! This wedge does not enter the casing completely; it rather rides between the hatch groove and the casing rim. Consequently, it uses the latch spring force to stay in this precarious position, in such way that spring force must fight the seal elasticity – that fights back!

Now imagine how the latch is stretched apart by all the described forces acting upon its material! Common plastics respond fine to being compressed, but can be as unpredictable as lottery when stretched.

Many outside influences can change the material resiliency. Changes may imperceptibly occur from wrong cleaning media (containing solvents), from heat, or sun-tan lotions, from gasoline or outboard engine oil that floats on water surfaces, and finally – from aging.

Once the material fatigue of the latch advances, the latch might snap – and quite without warning! If your camera case happens to be underwater and the outward-pressing seal forces the hatch open, your camera will suddenly and ingloriously drown, together with records of unique scenes that you have made. Might make you think certain thoughts about certain manufacturer and certain things… like a responsible design!

Even simpler than that; if the excenter-balanced latch snags on anything, it might inadvertently be opened… with pretty same results! And all because of the – ignored but present – forces in the wrongly conceived sealing system.

That, plus one lightning-fast moment of bad luck…

Unfortunately, I have no way to test the case impermeability right now, as the inclement weather conditions do not warrant a safe dive. But I’ll make sure to test the empty casing under pressure, prior to risking the valuable camera in it. Maybe I can replace the original seal with, say, twin o-rings that would properly fit the hatch groove – if I can find adequately dimensioned ones. I’ll also try to acquire the original casing from the Official source or Distributor, just to point out the differences. Will let you know.

In the meantime, remember that any and all damage to your camera – any camera – from water ingress is not covered by Warranty, and is routinely regarded as a User’s Fault!

Neat, eh? But then, that’s just one among many ways the new things get sold and bought.

Good Luck!

Disclaimer: The underwater case featured and reviewed in this article is a third-party product. It is not the casing officially produced by Xiaomi. In the upcoming weeks we hope that we will have a chance to review the original casing for the MiJia Mini, its performance and quality.