The Pebbles use vibrations to guide your breathing exercises. It is normal for these vibration mechanisms to produce some minor noise during their operation. If the noise is excessively loud or disruptive, it could indicate a problem.

Here are some steps to troubleshoot and resolve the issue:

1. Battery Level: A low battery can sometimes cause devices to behave unexpectedly. Charge your Pebbles fully and see if the noise persists.
2. Restart the Session: Let your Pebbles go into sleep mode and then wake them up to reset them. Performing a reset can often fix minor issues and glitches.
3. Ensure Correct Usage: Make sure you're using the Pebbles as intended. Misuse or incorrect handling might cause unusual sounds.
4. Check for Loose Parts: Gently shake the Pebbles and listen for any rattling or movement inside, which could indicate a loose component. If this applies, please seek professional help from the Glimp support team. Please do not attempt to open or disassemble the Pebbles yourself, as this could void the warranty and potentially cause further damage.

If the noise continues, please contact Glimp's customer support for further assistance. We can provide more in-depth troubleshooting or advise on the next steps, possibly including a warranty claim if necessary.