Yesterday we talked about water and dust, and today we’re looking at another major area of ruggedness, the drop spec!
A drop spec is a measure of a rugged handheld PDA’s ability to be dropped and is probably the most important aspect for some. In essence a drop spec is measured in height, either meters or feet and we think it’s used best as a relative value when looking at various rugged devices. The higher the value, the more robust the device is, but that’s not the whole story.
The MIL-STD covers many tests but when it comes to drop specs it’s the MIL-STD 810G that matters. This covers a whole host of rugged tests that the manufacturer can choose to undertake for a device it sells and the most commonly seen on the spec sheet are the ones below:
Tests how far a device can be dropped, it is a good measure of ruggedness but always be careful watch out for the testing procedures used. MIL-STD for instance has a procedure is does go some way to give a guarantee but the testing process also has some flaws in it too. Also check to see what floor type is being used in the drop test. So me drop to concrete, some steel, some vinyl covered floor!
This test tumbles the device 1000’s of times in more gentle but prolonged manner. It’s designed to simulate every day usage and gives a very different test to the more sudden impact nature of the drop test.
Some devices are also being tested for vibration resistance. Again this is a very different scenario to the drop and tumble tests and it checks to see just how well the device performs when presented with constant vibration.
Some rugged PDA’s are now being tested for thermal shock too which helps to see the behaviour of the plastics over a quick change in temperature. We’re not too sure just how appropriate this is to rugged PDA’s to be honest but some devices are starting to add this to the spec sheet. We’d think that if you’re working in a cold environment where a quick change in temperature is common, like going into a freezer for instance, then it could be something to look for.
So that just about covers off dropping, tumbling, vibrating and more. Next up we’ll talk about inherent rugged design and how that can be the most important factor of all.
The Rugged and Mobile blog.