This post is from Sandeep Mistry, Senior Software Engineer at Arduino. 

Today, we are pleased to announce BLE (Bluetooth Low Energy) central support in v1.1.0 of the ArduinoBLE library. This major feature addition allows your Arduino board to scan for and connect to BLE peripheral devices. With one simple library, you can now use BLE to directly connect your Arduino board to:

• A smartphone, tablet, laptop or PC 
• BLE peripherals (e.g. TI SensorTag) – NEW!
• Another Arduino board – NEW!

The ArduinoBLE library and new BLE central feature are supported on the following Arduino boards:

• MKR WiFi 1010
• Nano 33 BLE
• Nano 33 BLE Sense
• Nano 33 IoT
• Uno WiFi Rev. 2

Prior to this release, Arduino only officially supported BLE peripheral functionality on these boards. A BLE peripheral is typically used to expose some sensor data or actuators to another device BLE central capable device such as a smartphone or PC. With the new BLE central functionality, you’ll be able to wirelessly connect two boards together for communication or connect to a third party BLE peripheral, such as a TI SensorTag.

We think that the ArduinoBLE library is much easier to use than anything else out there and are excited to see what you build with this new capability!

The development journey

Back in 2015, the Arduino 101 was released, based on the Curie module developed by Intel. It was the first official Arduino board with on-board BLE support. The CurieBLE library initially only supported BLE peripheral mode.

After launch, the Arduino and Intel teams worked together to design an Arduino friendly BLE API that supported both BLE Peripheral and Central functionality. This was released later in 2016 in the v2.0 of the Arduino core for Arduino 101.

The BLE features of the 101 were also incorporated into the CTC 101 kit in many classrooms around the world. Students used smartphones or tablets for exercises in the kit to interact with project based lessons running on the board. Unfortunately, Intel decided to stop producing the Curie module in 2017, bringing the Arduino 101 board to end of life.

Last year, at Maker Faire Bay Area 2018, Arduino launched two new boards: the MKR WiFi 1010 and Uno WiFi Rev.2. Both boards use the u-blox NINA-W102 as a 2.4 GHz wireless module. Initially both boards only supported WiFi using the WiFiNINA library. However, the ESP32 chip inside the u-blox NINA-W102 supports Bluetooth classic and BLE as well.

Later in 2018, the Arduino core team was tasked with adding BLE support to the MKR WiFi 1010 board so that it could be used with the upcoming Arduino Science Kit Physics Lab product. The Science Kit Physics Lab product is another educational kit, targeted for students in the classroom. We had several choices to move forward, including:

• Bridging the ESP-IDF’s BLE API’s via RPC to the main MCU that sketches run on
• Basing things on the industry standard Bluetooth HCI protocol and investing in a Bluetooth HCI host stack as an Arduino library

The first option above was expected to take an equal amount of time to the second, but also would make the BLE library exposed to users highly dependent on the underlying firmware running on the ESP32. It was also not as portable to other chip sets in the future. Thus, ArduinoBLE was created. The NINA firmware only needed small change to bridge its virtual Bluetooth HCI controller to the UART pins of the module.

Earlier this year, we released the Arduino Nano 33 IoT and Arduino Nano 33 BLE boards. Since the Arduino Nano 33 IoT uses the same chipset as the MKR WiFi 1010, things worked out of the box. For the Nano 33 BLE, which is based on the Nordic nRF52840 chip, a new Arduino core was developed for this board based on mbed OS (see this blog post for more info). mbed OS includes a radio stack called Cordio, which provides both a Bluetooth HCI link controller and HCI host. Creating a single C++ class that interfaced with Cordio’s Bluetooth HCI link layer allowed us to re-use 95%+ of ArduinoBLE on this board.

After the Nano 33 BLE started shipping, there was even more demand for BLE central support. So, development for feature was scheduled and is now available. It combines the API designed for the Arduino 101 in CurieBLE ported on top of ArduinoBLE’s Bluetooth HCI host stack.

Many thanks to Tom Igoe, one of the co-founders of Arduino, for providing feedback on the official Arduino BLE libraries throughout the years.

We are excited to announce a new partnership with Chirp, a London-based company on a mission to simplify connectivity using sound. Chirp’s machine-to-machine communications software enables any device with a loudspeaker or microphone to exchange data via inaudible sound waves. 

Starting today, our Chirp integration will allow Arduino-powered projects to send and receive data wirelessly over sound waves, using just microphones and loudspeakers. Thanks to some compatible libraries included in the official Arduino Library Manager and in the Arduino Create — as well as further comprehensive documentation, tutorials and technical support — it will be easy for anyone to add data-over-sound capabilities to their Arduino projects.

Our new Nano 33 BLE Sense board, with a DSP-optimised Arm Cortex-M4 processor, will be the first board in the Arduino range with the power to transmit and receive Chirp audio signals leveraging the board’s microphone as a receiver. From now on, the Chirp SDK for Arduino will support the following boards in send-only mode: Arduino MKR Zero, Arduino MKR Vidor 4000, Arduino MKR Fox 1200, Arduino MKR WAN 1300, Arduino MKR WiFi 1010, Arduino MKR GSM 1400, Arduino MKR NB 1500 and the Arduino Nano 33 IoT.

Creative applications of Arduino and Chirp include, but certainly are not limited to:

• Triggering events from YouTube audio
• Securely unlocking a smart lock with sound 
• Sending Wi-Fi credentials to bring offline devices onto a Wi-Fi network
• Having a remote control that only interacts with the gadgets in the same room as you
  

“Connectivity is a fundamental asset for our users, as the demands of IoT uptake require devices to communicate information seamlessly and with minimal impact for the end user. Chirp’s data-over-sound solution equips our boards with robust data transmission, helping us to deliver enhanced user experiences whilst increasing the capabilities of our hardware at scale,” said Massimo Banzi, Arduino co-founder.  

“Sound is prevailing as a highly effective and versatile means of seamless data transmission, presenting developers with a simple to use, software-defined solution which can connect devices. Working with Arduino to extend the integration of data-over-sound across its impressive range of boards will not only increase the reach of Chirp’s technology, but provide many more developers with an accessible and easily integrated connectivity solution to help them drive their projects forward in all purposes and environments. We can’t wait to see what the Arduino community builds,” commented James Nesfield, Chirp CEO. 

To learn how to send data with sound with an Arduino Nano 33 BLE Sense and Chirp, check out this tutorial and visit Chirp website here.