From our everyday project life: Problems with the Bluetooth stack, e.g. in app development

Many manufacturers of locking systems or device controls use Bluetooth technology.

With its many advantages, this has rightly become established; Bluetooth is the first choice in many areas of application with its many protocol variants and many options.

However, problems with the Bluetooth stack from various manufacturers are regularly reported. Even the top dogs are affected by it - but they don't like to talk about it. We continue to help.

At first glance, the fact that such problems occur seems very surprising. Because don't we expect a technology manufacturer to have all the components of the system under control? And then validated accordingly, just as we check our results using a variety of methods and ensure quality. The problems that have become known are all the more astonishing...

But if we look a little behind the scenes, it quickly becomes clear why the errors that have become known are actually to be expected:
The errors almost always affect the software that is supplied as an accessory to the hardware. These are the communication classes that the manufacturer of the Bluetooth module supplies so that the customer can easily use the modules.
However, this software is delivered WITHOUT warranty. This is called, for example, “The assumption is that this software delivery is not being taken seriously. Because why else should one refuse to guarantee this?

And that’s exactly what we experience again and again in our projects:

The Bluetooth module meets the specifications, the software supplied has massive errors. Some of these are in the lowest protocol layers, so we can only correct the causes with special tools and our extensive experience or force the module manufacturer to correct their errors.

Example: App development for Apple and Android

In the module used by one of the largest manufacturers, there were repeated inexplicable dropouts when transferring large amounts of data. These appeared to occur sporadically. And only in the Android version of the app, the Apple app worked perfectly. The transfer of “normal” amounts of data was also error-free.
The first assumption was of course that there was a mistake with Android. Because Android is known for many flaws in the operating system.
After a long series of tests, it turned out that it was actually not Android but the manufacturer of the Bluetooth module that was to blame: There was an error in the management of the individual data packets at the lowest communication level, so that packets were repeatedly swallowed. We found this out through various traces and tests with special tools. The manufacturer then carried out a “silent update” of its software.

What are our recommendations to you as device control experts:

– Demand a full warranty from the manufacturer of the Bluetooth module, including for the software and sample classes supplied
– Subscribe to the manufacturers' special newsletters, in which fixes of the modules and software are communicated
– commission real specialists to select the manufacturer and module