Your average rugged mobile device with microSD card comes ready to run but you can also tweak and upgrade it so that it works perfectly for you or your business too.  One of the first things you probably need to look for in a mobile device is upgrading it’s storage capability via the MicroSD card.  Whilst 8GB or 16GB is more than adequate for most businesses using the expanded storage that an SD card brings is a cheap and powerful way to give your rugged smartphone a little extra usefulness.


What is a MicroSD Card

So lets kick off with a brief explanation of what an SD card is!.  Before microSD came simple old “SD” and these cards are to Android devices what a writable CD rom or USB flash stick is to a computer.  In fact you have probably been using SD cards for many years without realising in your camera or even with your PC too.

In a nutshell SD Cards are tiny, small plastic card-like chips that will expand the memory of the device they’re being used in.  They can be used to store anything form files to photos and can also be very useful to move your data from device to device as they’re portable.  MicroSD cards are just the latest name for SD cards.  They’re smaller, store more and are faster every time a new is brought out.


SD card types

Whilst most Android devices use MicroSD, lets talk about SD in general for a moment.  SD cards, like most technology are constantly improving which means new standards of SD cards are being brought out all the time.  Currenlty thpugh there are 2 main types you need to worry about.  SDHC and SDXC.  The only thing you need to remember is that SDXC cards are the newer standard and they bring bigger capacities, better speeds but are more expensive than the slightly older SDHC cards.


Physical Sizes of SD Cards, it’s not all about MicroSD just yet!

Sd cards still come in 3 sizes, although only 2 are largely used these days.  Firstly “Full-SD” are the cards you’ll probably be familiar with if you use digital cameras and they’re also the size that most laptops or PC’s have a slot for.  “Mini-SD” cards are about half the size and were common for a brief moment in certain Rugged PDA’s and Windows mobile smartphones.  Today the most common size is “MicroSD” and these are the cards that most rugged smartphones or tablets use today.

SD Cards come in 3 main sizes

SD Cards come in 3 main sizes

MicroSD cards usually come with an adapter that will allow them to be used in SD card slots so they can be easily used in cameras or PC’s but then also used in a smartphone when needed.  This also makes copying things like files and photo’s to your PC from your phone a doddle.


SD Card capacity

Just like a hard drive, SD cards can have all kinds of capacity.  I’d forget about 2/4 or even 8GB.  Whilst these cards can be bought for a few quid, these days it’s worth stretching a little bit more for 16/32 or even 64GB cards that make up the bulk of sales these days.  The newer cards now go up to 128, 256 and even 512GB but presently you need to spend top dollar to get these sizes and 256 upwards tend to only be on full SD card sizes.  There are 200GB microSD cards at this point in time.  Don’t worry though as in 6 months time this will all change as new, larger sizes hit the market, 128 and 256GB cards will become the norm and be available for £50 or so.

I’d always recommend getting the largest SD card you can.  They’re so versatile and portable that you’ll find them more usefull, the more capacity they have.  However for a business/enterprise rugged device, more than 32 GB is rarely needed and we do still sell our fair share of 8 and 16GB here too and it’s amazing just how much you can store on these cards.  If you’re taking a lot of photos or videos, say as part of an inspection  application then you need to consider larger sizes.  That goes for anyone who’s working with mapping or GIS and also if you want to bring your satnav maps onto your device.

Remember the larger pixels your camera, the larger those photo’s will be!


MicroSD card speeds

Another important factor when buying a microSD Card is the speed it can read/write data at and today there are 3 main standards to watch out for.

  • Class 10 – 10MB/s
  • UHS-1 20-50MB/2
  • UHS-2 150+ MB/s

You’ll probably still see class 6 or 4 cards for sale, but trust me, class 10 is what you need in 2016 as earlier classes are too old now!.

So why is speed important?

Well for a variety of reasons:

  1. Firstly like any hard storage technology, the faster it’ll read and write, the fast your device will be.  So even for general smaller tasks, you’ll probably notice a small difference.
  2. The more data you are storing the more you will see an advantage.  So if you have a 16MP camera and take lots of photo’s, all that time spent storing data will really add up.
  3. If you’re taking large photo’s or HD or even 4K video then the highest speed is a must, otherwise the card will simply not keep up.

One quick word of warning.  UHS-2 cards are very new at the time of writing and they also have a different pin out format so most smartphones currently can’t use them.  I’m sure this will change rapidly but just make sure you check first.

UHS-2 SD cards (on right) have a different pin out format

UHS-2 SD cards (on right) have a different pin out format


Device considerations

Before you go out and buy an SD card for your rugged mobile device, there’s just one other thing you need to be aware of.  Your device will have limitations on the type of card it can use.  This is often due to the OS version more than anything else but just take a quick check on the maximum capacities and speeds it can handle as well as what the spec of the device is or you will be wasting your money.

Most Android devices of the 4.2 to 4.4 era will use a Class 10 32GB card quite happily and to be honest the specs of these devices will mean this is more than adequate.  However a 64GB, UHS-1 card will also work in many device of this era and if you;re running Android v5.0 upwards things get a lot more interesting.  Always check your device specs before you buy or come ask me and i’ll be sure to help you.

About The Author

Dave's one of the founders of Raptor, his rants are memorable, his thoughts are stimulating and his heart is set on helping, entertaining and making things like mobile, Android, ruggedness, 3D printing and IOT simple.

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