About Bluetooth

Bluetooth is a 2.4GHz wireless protocol that is popular for short range - about 10 meters max. It's very low power and simpler than WiFi. That low power and simplicity has made it the most popular point-to-point wireless transport - you now get a Bluetooth transceiver in every phone, tablet and laptop.

There are, annoyingly, two flavors of Bluetooth: BT Classic and BT Low Energy (introduced as part of the Bluetooth 4.0 standard). And, annoyingly, despite the similar names, they are completely different and not cross-compatible.

Bluetooth classic is used for unstructured serial data transfer (sometimes called SPP), keyboards and mice, and audio such as BT speakers or BT headsets

Bluetooth LE is used for structured data (organized by 'Services', which are made up of individual 'Characteristics'), beacons, keyboards and mice, MIDI, but not audio. It is also the only method exposed to the user in iOS.

Basically the thing to watch for is if you want to communicate with SPP devices or BT audio, you can't use LE. If you want to work with iOS, you can't use Classic. Keyboards/mice can be either.

Feather nRF52840 Express (nRF52840)

Angled shot of a Adafruit Feather nRF52840 Express.
The Adafruit Feather nRF52840 Express is the new Feather family member with Bluetooth Low Energy and native USB support featuring the nRF52840!  It's...
$24.95
In Stock

The Feather nRF52840 builds on the nRF52832, the core and peripherals are very similar. It adds 2x the FLASH and 4x the SRAM and also comes with a native USB client peripheral. Like the nRF52832 Faether, it has only one chip on it - and that chip is both the processor you program and also the Bluetooth Low Energy radio. What's nice about this is you can do more powerful stuff, and faster too, because you don't have to manage two chips. It's also lower price and lower power since there's only one processor, and easier to put into sleep modes.

The native USB means that its great for Arduino or for CircuitPython support - no other BLE chipsets have USB!

Pros:

  • Code runs natively on the nRF52840 MCU, so it's fast, efficient and less expensive than the two MCU based nRF51 boards
  • Powerful ARM Cortex M4F processor with 1MB flash and 256KB SRAM
  • Native USB! Can act like a keyboard, mouse, MIDI or disk drive. Bootloader can be mass-storage based.
  • Supported by CircuitPython
  • Hardware UART pins are available for communicating to other peripherals (unlike the nRF52832 which needed them for the bootloader chip)
  • Better low power potential due to being a single chip solution
  • Because everything runs natively, a lot of complexity can be hidden behind simple helper classes, making things like ANCS possible and manageable compared to the nRF51.
  • Supports both Central and Peripheral mode, Central mode meaning it can behave like a phone and initiate connections to other peripherals, although Central SW support is in the very early stages at this point
  • Much more room to grow due to the MCU capabilities and flash/SRAM size compared to the earlier nRF51 or nRF52, and more advanced on board peripherals.

Cons:

  • A new chipset that is not an ATmega328 or ATmega32u4, so some older low-level Arduino libraries and techniques are not compatible. This doesn't happen a lot but if you're porting a project over, you'll have to watch for it!
  • Can not be used as a 'client' with your favorite MCU at the moment (unlike the nRF51), since code all runs natively (making this both a pro or a con depending on your needs).
  • Examples from the nRF51 and nRF52 are not compatible with each other since they have entirely different programming models.
  • Cannot use Bluetooth Classic

Feather nRF52840 Sense (nRF52840)

Angled shot of blue, rectangular, microcontroller.
The Adafruit Feather Bluefruit Sense takes our popular Feather nRF52840 Express and adds a smorgasbord of sensors...
$39.50
In Stock

Feather nRF52840 Sense takes our popular Feather nRF52840 Express and adds a smorgasbord of sensors to make a great wireless sensor platform. This Feather microcontroller comes with Bluetooth Low Energy and native USB support featuring the nRF52840!  This Feather is an 'all-in-one' Arduino-compatible + Bluetooth Low Energy with built in USB plus battery charging. With native USB it works great with CircuitPython, too.

Pros:

  • Same pros as the Feather nRF52840 Express
  • Includes LSM6DS33 Accel/Gyro + LIS3MDL magnetometer sensors
  • Includes APDS9960 Proximity, Light, Color, and Gesture Sensor
  • Includes PDM Microphone sound sensor
  • Includes SHT Humidity sensor
  • Includes BMP280 temperature and barometric pressure/altitude sensor

Cons:

  • Same cons as the Feather nRF52840 Express
  • Lacks a dedicated SWD connector, but has pads on the bottom

Feather nRF52 (NRF52832)

Video of an LED ring assembled on a half-size breadboard and microcontroller. A white hand changes the color of the LED ring by tapping colors on an app on a smart phone.
The Adafruit Feather nRF52 Bluefruit is another easy-to-use all-in-one Bluetooth Low Energy board, with a native-Bluetooth chip, the nRF52832!  It's our take...
$24.95
In Stock

The Feather nRF52 is a new direction compared to our 32u4 or M0 Bluefruit boards. This Feather has only one chip on it - and that chip is both the processor you program and also the Bluetooth Low Energy radio. What's nice about this is you can do more powerful stuff, and faster too, because you don't have to manage two chips. It's also lower price and lower power since there's only one processor, and easier to put into sleep modes.

Pros:

  • Code runs natively on the nRF52832 MCU, so it's fast, efficient and less expensive than the two MCU based nRF51 boards
  • Powerful ARM Cortex M4F processor with 512KB flash and 64KB SRAM
  • Better low power potential due to being a single chip solution
  • Because everything runs natively, a lot of complexity can be hidden behind simple helper classes, making things like ANCS possible and manageable compared to the nRF51.
  • Supports both Central and Peripheral mode, Central mode meaning it can behave like a phone and initiate connections to other peripherals, although Central SW support is in the very early stages at this point
  • Much more room to grow due to the MCU capabilities and flash/SRAM size compared to the earlier nRF51832, and more advanced on board peripherals.

Cons:

  • A new chipset that is not an ATmega328 or ATmega32u4, so some older low-level Arduino libraries and techniques are not compatible. This doesn't happen a lot but if you're porting a project over, you'll have to watch for it!
  • Can not be used as a 'client' with your favorite MCU at the moment (unlike the nRF51), since code all runs natively (making this both a pro or a con depending on your needs).
  • Examples from the nRF51 and nRF52 are not compatible with each other since they have entirely different programming models.
  • Cannot use Bluetooth Classic
  • UART pins (RX/TX) are not available for connecting to sensors/wings, as they are used for programming and debug of the native chip.

We also carry a special Feather - unlike the rest of the Feather family, this board is not for use with Arduino IDE. Instead, it is for use with Mynewt only! We have programmed it with the Mynewt bootloader and updated the hardware to add an SWD connector and an additional DFU button. This Feather is for advanced users only, you will be interacting with the Mynewt RTOS rather than Arduino, and you cannot easily go back-and-forth without an SWD programmer.

Faded image of a rectangular microcontroller and text that reads "my newt".
The Adafruit Feather nRF52 Pro is another Bluetooth Low Energy board for advanced projects and users who want to use a fully open-source Bluetooth Low Energy...
$27.50
In Stock

Feather Bluefruit M0 and 32u4

Angled shot of rectangular microcontroller.
Feather is the new development board from Adafruit, and like its namesake it is thin, light, and lets you fly! We designed Feather to be a new standard for portable microcontroller...
$29.95
In Stock
Angled shot of rectangular microcontroller.
Feather is the new development board from Adafruit, and like its namesake, it is thin, light, and lets you fly! We designed Feather to be a new standard for portable microcontroller...
$29.95
In Stock

Our original Bluefruit Feathers are the 32u4 and M0-based. These pairs are very similar looking, and have the same basic idea behind them: there is a main processor which is an ATmega32u4 or ATSAMD21 and a co-processor module which is the red and silver rectangle, containing an nRF51 which can do Bluetooth Low Energy only.

The nRF51 is programmed with our Bluefruit firmware, and can be controlled with AT commands over SPI connection. When the main processor (32u4 or M0) wants to send or receive BLE data, it sends commands to the co-processor module. We decided to go this way because the nRF51 did not have as-good a programming setup as the nRF52, and we thought people would have a better experience if the main chip was not also doing the radio work.

That said, if you already have code for the 32u4 or M0 chips, this is an easy upgrade, you get all the peripherals you know and love. This may be easier for beginners who are not quite ready to work with the native nRF52

Pros:

  • Familiar 32u4 and M0 chipsets
  • No need to worry about the Nordic 'softdevice' radio thread interrupting timing-specific code since the radio is completely separate.
  • Lots of existing code and projects

Cons:

  • Can only act as Peripheral, not Central
  • More expensive as it is a 2-chip solution
  • Higher power draw
  • Can't take advantage of new nRF52 capabilites as the firmware is updated and released by Nordic
  • Cannot use Bluetooth Classic

ESP32 Feather

Angled shot of rectangular microcontroller.
Aww yeah, it's the Feather you have been waiting for! The HUZZAH32 is our ESP32-based Feather, made with the official WROOM32 module. We packed everything you love...
$19.95
In Stock

Even though this is primarily considered a WiFi Feather, the ESP32 does contain a BT LE and BT Classic radio! That's right this is the only Feather that can do BT classic. It's also the only one that can do WiFi and BT (altho, as of this writing, it cannot do both at once)

Sounds great, right? Well, there's some caveats. As of this writing, May 2017, the ESP32 Bluetooth core is still under development and there's only one basic beacon example for use with the Arduino IDE core. So we put this one at the bottom of the list. You can check the ESP32 Arduino core and what has been added here, if there's an example for what you want to do, then you're in luck!

Once there's more working examples, we can fill out the pros and cons more. Right now we think it should only be used by bleeding-edge developers who are cool with running weekly regression tests on their project.

Pros:

  • All-in-one Feather can do anything and everything (except make you a sandwich)
  • Fast dual-core processor
  • Low cost

Cons:

  • Still waiting on integration and support for BT and BTLE radio

ESP32 V2 Feather

Top view of black rectangle-shaped microcontroller.
One of our star Feathers is the Adafruit HUZZAH32 ESP32 Feather - with the fabulous ESP32 WROOM module on there, it makes quick work...
$19.95
In Stock
Angled shot of rectangular microcontroller.
One of our star Feathers is the Adafruit HUZZAH32 ESP32 Feather - with the fabulous ESP32 WROOM module on there, it makes quick work...
$19.95
In Stock

Like the ESP32 Feather, the V2 also has Bluetooth Support.

Pros:

  • Same advantages as the original ESP32
  • Compared to the original Feather with 4 MB Flash and no PSRAM, the V2 has 8 MB Flash and 2 MB PSRAM
  • On-board STEMMA-QT connector

Cons:

  • Some pins have moved from the original ESP32, so some examples may not work without modification

ESP32-S3 Feather

Angled shot of rectangular microcontroller.
The ESP32-S3 has arrived in Feather format - and what a great way to get started with this powerful new chip from Espressif! With dual 240 MHz cores, WiFi and BLE support, and native...
$17.50
In Stock

The ESP32-S3 has dual cores just like the ESP32 but adds native USB so it can run CircuitPython. It also has support for Bluetooth Low Energy.

Pros:

  • Native USB so it can run CircuitPython
  • 240MHz Tensilica processor with dual cores
  • Comes with 8 MByte of Flash
  • Supports BLE
  • Low-power friendly

Cons

  • No Bluetooth Classic Support
  • No PSRAM

This guide was first published on May 14, 2017. It was last updated on Mar 08, 2024.

This page (Bluetooth Feathers) was last updated on Mar 08, 2024.

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