Yes. Ethica provides participants with a few different ways to stop the data collection any time they want, either permanently or temporarily.
If you want participants to be able to permanently disable a data source, but still be part of the study, you can set that data source to optional. This instructs the Ethica app to give participants this option to opt out from this data source if they choose to.
Participants can also temporarily disable data collection at any time by going to the app and pressing "Pause Participation". This will stop all automatic data collection for one hour. The data collection will resume automatically after one hour. Note that participants will continue to receive surveys during this time, if there are any surveys scheduled.