Bluetooth: The Next Generation

Bluetooth has never had a reputation as being easy to work with, however with the arrival of the new Bluetooth 4.0 standard, and specifically Bluetooth Low Energy, it’s not only become a lot easier to work with, but it’s become a lot more useful. Especially to makers, who now have a really low powered, flexible, wireless technology available to them.

There has been support for Bluetooth LE in iOS for some time, and support has increased with the recent announcements around iOS7 at WWDC a couple of weeks ago. However until recently there was limited support on Android, however with the announcement last month at Google I/O that the next generation of the Android operating system will support Bluetooth LE, both of the major mobile platforms now support the standard.

However it’s only been the last few months where support on the other end, the micro-controller side of things, has begun to take off. System-on-a-chip and Bluetooth modules, for instance from Bluegiga, Texas Instruments and Nordic, have been available for a while now. However easy to use boards offering serial interfaces like Kroll’s BLE Shield, or the RedBearLab‘s BLE Shield and BLE mini board, are really only now becoming available in quantity.

Which of course means that we’re probably ready for the next step, which is Bluetooth LE in an Arduino compatible form factor. There are two really interesting projects on Kickstarter right now.

Ember and Torch are Arduino-compatible boards with built-in Bluetooth LE support.

A 16MHz ATmega32u4 based board with Arduino standard form-factor and Nordic nRF8001 Bluetooth LE.

An 8MHz ATmega32u4 based board with Arduino mini form-factor and Nordic nRF8001 Bluetooth LE.

The first is Ember & Torch, two Arduino-compatible boards with built in Bluetooth LE. Torch is a Arduino software and pin compatible board, while Ember comes in an Arduino mini form factor.

However the most interesting thing about Ember & Torch isn’t the hardware, it’s the Bonfire library that will ship with the boards. With support on the Arduino and iOS/Android side it allows you to attach a function to an event. So for instance if you want to send a sensor update from the Arduino to your phone, you’d “emit” an event inside the Arduino main loop, which would be bound to a callback block on the iOS end of things (and vice versa). It looks like a flexible system, and one level of abstraction above the straight serial interfaces that have been available up till now.

The Arduino-mini sized BLEduino is breadboard compatible.

The BLEduino (left) can be made pin-compatible with the standard Arduino layout using the Shield-Shield.

The other interesting project is the BLEduino. Interestingly, while the board also comes in an Arduino mini form factor this project have invented something they’re calling the Shield-Shield which slips underneath the BLEduino board to give it a standard Arduino form factor and pin out. It’s a rather ingenious idea actually, and while I’m sure it’s not a new one, it’s not something I’d come across before.

http://www.kickstarter.com/projects/kytelabs/bleduino-bluetooth-40-ble-made-easy-arduino-compat

Unlike the Ember & Torch there isn’t as much detail on how data is sent across Bluetooth LE between the board and the phone. However for those of you that aren’t iOS or and Android developers the BLEduino is also going to ship with an iOS application that will let you take control of the board without any programming on the mobile platform end.

Both projects look interesting, and I’m hoping that both pass their Kickstarter goals and get funded because they’re different enough that I’d like to play with both.

Going forward I’d eventually like to see a board that allows you to define its GATT profiles programmatically. It’s theoretically it is possible, I think that while not particularly well documented the Nordic chipset will let you do this at run time, and it would let you turn your Arduino into an “arbitrary” Bluetooth device. Which would be pretty cool, because that means that any iOS or Android application designed to work with that sort of Bluetooth device would talk to your Arduino board without doing anything programmatic on the mobile side of things.