Help & Support

If you are struggling to connect your micro:bit to the machine learning tool, try these steps.

Throughout this article, the micro:bit worn by the user is referred to as the 'remote micro:bit'.

Which connection approach are you using? 

The Machine Learning tool offers 2 ways to connect to your micro:bit:

• Radio - using 2 micro:bits: for the BBC micro:bit the next gen playground survey, the default approach is to use 2 micro:bits. One is connected to the computer and the other is worn on the user's wrist. With this approach, the micro:bits communicate with each other using bespoke radio communication.
• Bluetooth - using 1 micro:bit: if you are using one micro:bit worn on the user's wrist then the micro:bit communicates directly with the web browser using Web Bluetooth.

If you are using the machine learning tool as part of the BBC micro:bit the next gen playground survey, you will use the radio approach by default. To switch to the Bluetooth approach choose, Alternative method if you only have 1 micro:bit (link at the bottom left of the What you will need to get started window). This alternative approach uses Bluetooth. 

To troubleshoot your issue it is worth noting which connection approach you are using. 

Check your web browser and device

Please use a Chrome or Edge web browser with the machine learning tool (other browsers, such as Safari or Firefox, often do not allow WebUSB which is essential for this tool).

Unfortunately, the machine learning tool does not work with mobile devices (e.g. iPads or Android devices). Please use a computer instead. 

Proximity

Whether you are using radio or Bluetooth to connect, there is a limit to how far apart the micro:bit and computer can be. If you are experiencing connection issues, bringing the remote micro:bit close to the computer is a good first step. 

Batteries and power

When battery power is low, Bluetooth and radio can fail even when the micro:bit appears to have power. 

1. Try replacing the batteries on the remote micro:bit with brand new ones and check the remote micro:bit has power (the red light on the back is on). 
2. If you are using the radio connection approach, check that on the back of the micro:bit connected to the computer, the red light (power) is on and the orange light is either on or blinking. The orange light indicates that the USB is connected to the computer. Also ensure you are using the USB cable that came with your micro:bit (or if you are using a different cable it must send both power and data, some USB cables only send power).

Start the connection process again

If problems occur, try starting the connection process from the beginning, going through the steps to put the hex files onto each micro:bit (or just the one if using Bluetooth) and enable WebUSB and, if necessary, Web Bluetooth on the computer. 

You will see windows like the one below during the process. Be sure to select the micro:bit (in this case 'BBC micro:bit CMSIS-DAP - Paired' but it might have a different name for you) then choose the Connect button for each of these windows. 

Try the alternative connection approach

If you have tried to connect using the 2 micro:bit radio method, try the 1 micro:bit Bluetooth method instead or vice versa. This can be particularly helpful if there is interference from other devices in the area you are in (which may particularly affect the radio connection approach). 

Note that the Bluetooth method will require you to have Bluetooth enabled on your computer and Web Bluetooth enabled on your Chrome or Edge web browser. 

To choose the Bluetooth approach, select 'Alternative method if you only have 1 micro:bit' in the first connection window titled 'What you will need to get started'. 

Enable Bluetooth, WebUSB and Web Bluetooth

Note the Bluetooth settings below are only required for the Bluetooth connection approach. Only WebUSB is required for the radio connection approach.

Some computers do not have Bluetooth and so must use the radio approach instead. Please check your computer does have Bluetooth and that it is turned on before trying the Bluetooth approach. 

Turn on Bluetooth (if using Bluetooth approach)

In Windows:

1. Go to Start  > Settings > Bluetooth & other devices.

2. Switch Bluetooth on.

In MacOS:

1. Click the Bluetooth status icon in the menu bar.

2. Choose Turn Bluetooth On.

Enable WebUSB and Web Bluetooth (if using Bluetooth approach)

Please use Chrome or Edge web browsers with the machine learning tool. Please ensure these are set up to allow the user to grant access to WebUSB or Web Bluetooth devices. (For school or enterprise systems, browsers can be set up in a way that will automatically deny requests to access Web Bluetooth or WebUSB - please speak to your IT specialist if you think this might be the case). 

If you have control over your Chrome or Edge settings yourself then check your WebUSB device setting. 

For example, if you have control of Chrome settings, to enable you to connect to WebUSB devices: 

• Go to 'Chrome settings' using the 3 vertical dots menu on the top right of the browser
• Select 'Privacy & security', then site settings
• Under 'Permissions' choose, 'Additional permissions'
• Then choose 'USB devices' and ensure 'Sites can ask to connect to USB devices' is selected

There is no equivalent setting for Web Bluetooth for individual users in Chrome, it is typically enabled by default. However, on school or enterprise systems, both WebUSB and Web Bluetooth are controlled centrally by an IT specialist. IT specialists using enterprise additions of Chrome or Edge should look up browser policies relating to the control of Web Bluetooth API  and WebUSB API (e.g. DefaultWebBluetoothGuardSetting and DefaultWebUsbGuardSetting) to ensure users can connected to USB and Bluetooth devices.

What are the LEDs telling you? 

The LEDs on the front of the micro:bit may help you to understand the status of your connection:

Radio connection (2 micro:bits)

Shown on LEDs	When?
	The remote micro:bit will show a dot very briefly on the display on startup until it starts to broadcast radio data. This may be too quick to notice.
happy face on remote micro:bit	The remote micro:bit will show a smiley face when it is broadcasting data.
dot (not flashing) on micro:bit connected to the computer	The micro:bit connected to the computer will show a dot very briefly on the display on startup until it starts to stream data to the web browser. This may be too quick to notice.
	The micro:bit connected to the computer will show a diamond while it is streaming the data it is receiving from the remote micro:bit to the computer's web browser.
	The micro:bit connected to the computer will show a flashing dot if it stops receiving data from the remote micro:bit.

Bluetooth connection (1 micro:bit)

Shown on LEDs	When?
happy face on the micro:bit	The  micro:bit will show a happy face briefly on the display on startup.
pattern to identify the micro:bit (exact pattern is specific to your micro:bit)	The  micro:bit will show a pattern until the Bluetooth is connected. This pattern will be specific to your micro:bit and will probably look different to the pattern in this example image.
happy face on the micro:bit	While Bluetooth is connected, your micro:bit will show a smiley face.
	If the Bluetooth connection is lost, the micro:bit will show a sad face for about 2 seconds.
pattern to identify the micro:bit (exact pattern is specific to your micro:bit)	If the Bluetooth connection is lost, after 2 seconds, the micro:bit will show the pairing pattern again. This pattern will be specific to your micro:bit and will probably look different to the pattern in this example image.