Text Box 1 Limitations of passive sensing data collection with a smartwatch

For a non-depressed mother (19–22 years), it was her first experience of using a smartwatch. She did not have a problem attaching the beacon on the child’s clothing. However, she felt uncomfortable wearing the watch on her wrist. This was largely due to her workload at home – she washed clothes and did dishes multiple times a day, which necessitated her to get her hands and arms wet. She was concerned about possible water damage to the watch. She also had trouble keeping the watch charged because it lost battery quickly. Her husband helped her complete the study, providing reminders and assistance charging the watch. We collected 62.5% and 51.9% audio and proximity data but were unable to collect GPS or activity data due to limited functionality of the smartwatch.