In order to use the Bluefruit Playground app, you'll need to load special uf2 firmware file on your Circuit Playground Bluefruit (aka – CPB) or CLUE. The firmware is simply an Arduino program supplied as a UF2.

Alternatively, you can use a CircuitPython program that is equivalent to the firmware. There are versions of the  CircuitPython program for the CPB, CLUE, and Feather Sense nRF52480, and it's easy to adapt the code to your custom setup with a board that supports CircuitPython with BLE and the sensors you've connected.

If you're just starting out, we recommend this standalone firmware page. More advanced folks who want to see the internals could use the CircuitPython version

Download uf2 file

Circuit Playground Bluefruit users should click the button below to download the Bluefruit Playground uf2 firmware file and save it to your computer:

CLUE users should click the link below to download firmware for their device:

(For developers interested in the source code for the firmware and other details, see the BLE Services page in this guide. But you don't need to read or understand that page to use the app.)

Upload firmware to device

Connect your board to your computer via a known good USB data cable (not a "charge-only" cable!).

Double-click the Reset button near the center of the board. You should see your board's LEDs turn red, then green.

A new drive will appear on your computer with the following name:

  • Circuit Playground Bluefruit users will see a drive named CPLAYBTBOOT
  • CLUE users will see a drive named FTHR840BOOT (or similar)

Drag the Bluefruit Playground uf2 file onto the drive to copy it to your device.


Once the uf2 file is finished copying, your device will reboot – its NeoPixel LEDs will turn off, and its drive will disappear from your computer.

You're now ready to connect to your device using the Bluefruit Playground app.

This guide was first published on Dec 16, 2019. It was last updated on Dec 16, 2019.

This page (Standalone Firmware) was last updated on Dec 11, 2019.

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