electronut/ElectronutLabs-bluey

What is Bluey?

Bluey is an Open Source BLE (Bluetooth Low Energy) development board with Temperature, Humidity, Ambient Light and Accelerometer sensors.

Bluey uses the Nordic nRF52832 BLE SoC (System on a Chip) which has an ARM Cortex-M4F CPU and a 2.4 GHz radio that supports BLE and other proprietary wireless protocols. It also supports NFC, and in fact the board comes with a built-in NFC PCB antenna.

Specifications

Nordic nRF52832 QFAA BLE SoC (512k Flash/ 64k RAM)
TI HDC1010 Temperature/Humidity sensor
APDS-9300-020 ambient light sensor
ST Micro LSM6DS3 accelerometer
CREE RGB LED
CP2104 USB interface
2 push buttons
Coin cell holder
Micro SD slot
2.4 GHz PCB antenna
NFC PCB antenna

Getting Started with Bluey

Bluey is shipped with either Arduino bootloader or Nordic DFU-OTA bootloader as per the selection at the time of purchase. While Arduino bootloader facilitates programming Bluey using Arduino IDE via serial USB cable, Nordic's DFU-OTA bootloader allows the user to update device firmware using Nordic's software development kit (SDK) and nRF Connect mobile application over bluetooth.

We have created an Arduino library with example projects to help you get started quickly.

Guide: Using Arduino

Guide: Using Nordic SDK

Guide: Using Arduino

Installation

Uploading without programmer requires bootloader programmed on the board. The repo electronut/bluey_serial_dfu_bootloader contains the source and precompiled hex file of the bootloader as hex/s132_nrf52_2.0.0_softdevice.hex.

The bootloader has the softdevice s132 in it, so no other action is needed to use the BLE Peripheral library.

Bootloader mode is triggered by pressing and holding both prss buttons on bluey and releasing the reset button. The blue LED will start blinkng at an accelerating rate repeatedly to indicate that the bootloader mode is active.

Board Manager

Download and install the Arduino IDE (At least v1.6.12)
Start the Arduino IDE
Go into Preferences
Add https://raw.githubusercontent.com/electronut/arduino-boards/master/package_electronutlabs_boards_index.json as an "Additional Board Manager URL"
Open the Boards Manager from the Tools -> Board menu and install "Electronut labs nRF5 Boards"
Select 'Electronut labs bluey' from the Tools -> Board menu

NOTE: During installation it takes the Arduino IDE a few minutes to extract the tools after they have been downloaded, please be patient.

Uploading Bootloader

Although Bluey is shipped with the bootloader that enables programming the device using Arduino IDE, in case you erase the bootloader from Bluey, it is possible to flash it again using a Bumpy.

Steps

Download bootloader
Open command prompt and access the directory containing bootloader hex file.
Follow steps as mentioned in the Bumpy github repository to connect and attach to Bluey target.
Issue: load s132_nrf52_2.0.0_softdevice.hex command. Wait for the command to execute and load the file completely.
Issue: detach command to free the target.
Issue: Quit command to close arm-gdb debugger.
Unplug Bumpy.
Connect Bluey to your PC via USB cable. You should notice the familiar blue LED blinkking at an accelerating rate, indicating Bluey is in bootloader mode.

Usage

After tools installation, you can now select "Electronut labs bluey" from the tools menu, and other related options.
Bluey comes preprogrammed with serial DFU bootloader, which Nordic's nrfjprog utility can program using serial connection. To trigger bootloader, press and hold button1, press the Reset button and then release button1.
Bluey's blue LED will start blinking in a 'timebomb' pattern, indicating that it is in DFU bootloader mode. Now you can press upload button in arduino IDE to program your code.
Bluey library for arduino is available at ElectronutLabs_Bluey_Arduino_Library repository. Download the zip file from github repository and extract the files to Documents/Arduino/libraries directory for Windows OS.

Steps

Set the device in bootloader mode. To trigger bootloader, press and hold button1 (SW3) , press the Reset button (RST) and then release button1.
Go to: Tools > Boards. Select Electronut labs Bluey.
Go to: Tools > Softdevice. Select S132.
Ensure Low Frequency Clock is set to Crystal Oscillator under Tools menu.
Select appropriate COM Port assigned to Bluey.
Click on Upload under Sketch menu or use Ctrl + U combination to upload code to Bluey.
Once code is upload, perform a manual reset by pressing RST button once.

Pin mapping

                    Connector P3 on bluey

     A0       P0.02/AIN0   | 1   2 | P0.26        D0
     A1       P0.03/AIN1   | 3   4 | P0.27        D1
     A2       P0.04/AIN2   | 5   6 | P0.24/AIN4   A3
     D2            P0.22   | 7   8 | P0.29/AIN5   A4
     D3            P0.23   | 9  10 | P0.30/AIN6   A5
     D4            P0.24   | 11 12 | P0.31/AIN7   A6
     D5            P0.25   | 13 14 | Ex_vin
                     GND   | 15 16 | 3v3
                     GND   | 17 18 | GND

          button D6  - P0.16
              R  D7  - P0.19
              G  D8  - P0.18
              B  D9  - P0.17

      D10     SCL - P0.11    DRDYn - P0.12   D11
      D12     SDA - P0.13      INT - P0.14   D13
      D14    INT1 - P0.15     INT2 - P0.20   D15

              RXD - P0.08    TXD - P0.06
              RTS - P0.05    CTS - P0.07

              SS - P0.22    SCK - P0.25
            MISO - P0.24   MOSI - P0.23

LED and button pins can be referenced by PIN_LEDR, PIN_LEDG, PIN_LEDB ,LED_BUILTIN (red one), PIN_BUTTON in arduino code.

Low Frequency Clock Source (LFCLKSRC)

Bluey has an external 32 kHz crystal connected, thus, it will be used as the source for the low frequency clock. The internal 32 kHz RC oscillator can be used by removing the external crystal. The low frequency clock is used by the delay(ms) and millis() Arduino API's.

Bluey has an additional menu item under Tools -> Low Frequency Clock that allows you to select the low frequency clock source.

BLEPeriphial Arduino Library

arduino-BLEPeripheral library can be used creating BLE applications with bluey. Follow installation steps on it's README. See the library's API for more details on usage.
Ensure that Softdevice:"S132" is selected under tools menu. This is essential to compile BLE examples.
NOTE: Although the description says "nRF8001 or nRF51822", but nRF52832 is also supported because despite changes in CPU and peripherals, the radio interface is identical in both (API is same, but there might be changes in power/sensitivity etc.)
Once installed, you can see examples for this in examples menu. You can run most examples without modifications, unless some specify LED or button pins different from bluey's, in which case, just replace pin numbers with LED_BUILTIN, or PIN_BUTTON etc.
Use nRF connect (and other apps from nordic on play store) to scan, connect, interact with BLE peripherals created with these examples.

Guide: Using Nordic SDK

To get a project up and running with bluey, you need to first build the code to generate a .hex file and then upload it to the board.

Building code for Bluey

If you are just getting started with the nRF52832, we recommend that you set up and use the Nordic nRF5 SDK for programming bluey. Click here to read our Getting Started with nRF5 SDK guide.

Uploading code to Bluey

There are two main ways of uploading code into bluey:

Use the built-in OTA (over the air) bootloader which lets you upload code using a phone. Click here to read about this option.
A much more powerful option is to use an external programmer that can both upload and debug your code. Here are a few ways of doing this:
1. Use our inexpensive Black Magic Probe compatible Bumpy SWD programmer which was designed exactly for this purpose.
2. Using a cheap programmer loaded with Black Magic Probe firmware. Click here to learn about this option.
3. Using the Nordic nRF52-DK. Click here to explore this option.

Powering Bluey

You can power bluey in several ways:

Using the 5V micro USB connector (which also gives you the option to print debug messages via UART).
The + / - power supply pins which can take regular 2.54 mm header pins, a JST connector for a 3.7 V LiPo battery, or a 3.5 mm terminal block.
A CR2032 coin cell for low power applications.

The sensors on bluey require a minimum of 2.7 Volts to function properly. Please note that the maximum power supply to bluey is 6 Volts. Do not exceed it! We also have reverse polarity protection on all power supplies, but better not to tempt fate. :-)

What can you do with Bluey?

You can use bluey for a wide range of projects. The BLE part is ideal for IoT projects, or if you want to control something with your phone. The nRF52832 SoC has a powerful ARM Cortex-M4F CPU, so you can use this board for general purpose microcontroller projects as well.

With BLE and useful built-in sensors, bluey is a great platform for learning IoT, BLE programming, ARM, and microcontrollers in general. In fact, it's being currently used in Embedded Systems training courses.

The code folder in this repository has a bunch of interesting demo projects that we have built using bluey - so do take a look!