Bluetooth issues with the micro:bit can be incredibly frustrating, especially when you just want to test your project and move on.
Usually, when a micro:bit isn't visible to your computer, phone, or tablet, it comes down to either the device not being in the correct pairing mode, or the code currently on the micro:bit not having Bluetooth enabled.
Here is a step-by-step guide to get your micro:bit visible and connected.
The micro:bit does not constantly broadcast its Bluetooth signal; you usually have to tell it to look for a connection.
Hold down Button A and Button B on the front of the micro:bit at the same time.
While holding both buttons, briefly press and release the Reset button on the back.
Keep holding Button A and Button B until you see the Bluetooth logo (a 'B' shape) appear on the LED matrix, followed by a pairing pattern.
Check your device's Bluetooth menu again to see if it appears.
If you have connected this specific micro:bit to your device before, a previous pairing might be confusing the connection.
Go to your phone, tablet, or computer's Bluetooth settings.
Find the micro:bit in the list of paired devices.
Select "Forget this device" or "Unpair".
Try putting the micro:bit back into Pairing Mode (Step 1) and connecting from scratch.
By default, MakeCode disables Bluetooth to save memory and power, prioritizing the "Radio" feature instead. If you are trying to connect to the micro:bit to send data to an app, you need to enable Bluetooth in your code.
Open your project in MakeCode.
Click the Gear icon (Settings) in the top right corner.
Select Project Settings.
Look at the Bluetooth connection options. Change it to "No Pairing Required: Anyone can connect via Bluetooth" (best for testing, though less secure) or "JustWorks pairing".
You will need to download this new code via a USB cable first before the Bluetooth changes take effect.