Swan From Blues Wireless Is the Most Expandable Feather-Compatible Board to Date

Low-power, STM32, 55 GPIOs, castellated edges, and support for cellular connectivity with carrier boards.

James Lewis
3 years agoInternet of Things

Blues Wireless connects devices to cloud applications. Their Notecards contain cellular modems that work with their Notehub service. Their most recent hardware introduction is Swan, a Feather-compatible board with an STM32 microprocessor. Its castellated edges, built-in load switch, and 55 GPIOs set it apart from other Feathers on the market.

"Swan is the most extensible Feather-compatible MCU on the market today." — Blues Wireless

Swan has an STMicroelectronics STM32L4R5 microcontroller running at 120 MHz. The STM32's key highlights are 650 kilobytes of RAM, 2 megabytes of flash, and 55 GPIO pins. As you might expect in an STM32-based board, standard features like SPI, Quad SPI, I2C, UART, USB OTG, and RTC are available.

The Feather-compatible IO pins around the board have castellated edges. There are two advantages to this approach. The first is making all 55 GPIOs available to either a custom PCB or a Notecarrier board. (The "extra" signals are between the Feather-standard pins.) The second is that these edges make it possible to solder the entire board to an end-product. This feature means you can use the same board for prototyping and in production.

Power can come from either the USB port or a battery. There is an onboard regulator that software can switch off, making it easy to power down external peripherals. This regulator outputs up to two amps. Once the STM32 turns off external devices and goes into a low-power mode, Swan only draws eight microamps!


Notecarrier boards are aids for prototyping and developing IoT applications. Blues Wireless plans to offer Notecarrier-AF specifically for Swan. This board accepts both the Swan's Feather footprint and a Notecard. The Notecard contains a system on a module (SoM) with a cellular radio. Together, the Swan and Notecard connect to the Notecarrier, enabling communication on an NB-IoT or LTE-M network.

Once Swan connects with Notecard, it can communicate with third-party cloud applications through Blues Wireless's Notehub. Notehub.io manages the fleet of cards, manages events between the device and cloud, and simplifies over-the-air OTA updates. This video is an excellent high-level overview of Notehub.

Swan and Notehub support the most popular embedded programming environments such as STMicro's STM32CubeIDE. Other programming environments like Visual Studio Code, IAR, and the Arduino IDE also work in the Blues Wireless ecosystem. For those looking for rapid application development, even CircuitPython has a port for the Swan.

For more information

Swan is now available on the Blues Wireless website for $25. Additionally, a pre-order Starter Kit with Swan, a Notecard with NB-IoT and LTE, and the Notecarrier-AF are available for $99, with shipments expected at the end of October. For more details on Swan and Blues Wireless, check out this introduction post.

The Blues Wireless team will hosting a Hackster webinar on October 26th. Register here!

James Lewis
Electronics enthusiast, Bald Engineer, and freelance content creator. AddOhms on YouTube. KN6FGY.
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