[barbegal]

Sadly this book is probably of limited use because it doesn't appear to cover getting BLE (Bluetooth low energy) to work with Android and iOS.

Using BLE according to the standards is relatively simple if you have control over both ends of the communication link. Unfortunately in most cases you have a BLE device that you wish to talk to a smartphone or tablet. In this case you have no control over one end of the link because that is controlled by the smartphone chipset and the OS (Android or iOS). Getting BLE to work well and consistently across a range of smartphones and tablets is tricky because the API has changed between OS versions, with Android becoming more focused on preserving battery life rather than offering developers a way to make BLE work in the precise way they want. In addition chipset differences means even with the same version of the OS you get different behaviours especially when multiple BLE devices are involved.

Lots of the nice stuff in the standards flat out doesn't work with iOS and Android. Out of band pairing (except NFC pairing on Android) doesn't work meaning in most cases you have to revert to insecure pairing methods because your BLE device has no user interface.

[mafaneh]

First, a disclaimer that I'm the author of the e-book listed.

Yes, I agree that getting BLE to work with smartphones is not an easy task. The APIs are ever-changing and evolving and differ across different devices as well. In the end, though, they must adhere to the official specification and provide an interface to the underlying protocol.

There are many embedded developers that are looking to learn the protocol and don't know where to start (myself included, especially when I first starting learning the technology). The specification is quite overwhelming and there is a lack of resources that cover both theory and implementation together.

The book is targeted at embedded developers with the goal to help them learn the basics of the technology by guiding them through various exercises and examples. There are also many new use cases popping up where an embedded platform is used on both ends making the task easier (compared to pairing with a smartphone app).

[SlowRobotAhead]

Yes and maybe.

A lot of the BLE5 spec like 2Mbps transfers is negotiated, and Apple specifically has an interest in always choosing the fastest reliable speed or biggest MTU.

SO YES, you are currently at the mercy of Apple and Android to support BLE5 which iirc only iPhone 8/X do for Apple - and yes, it’s confused that to be a “BLE5” device you don’t even need to use all BLE5 features - but it’ll get there.

I’m shipping a BLE5 device soon, it’ll be 99% BLE 4.2 features, it’ll update as available.