  Collecting mobile datasets remains challenging for academic researchers due
to limited data access and technical barriers. Commercial organizations often
possess exclusive access to mobile data, leading to a "data monopoly" that
restricts the independence of academic research. Existing open-source mobile
data collection frameworks primarily focus on mobile sensing data rather than
screen content, which is crucial for various research studies. We present
Crepe, a no-code Android app that enables researchers to collect information
displayed on screen through simple demonstrations of target data. Crepe
utilizes a novel Graph Query technique which augments the structures of mobile
UI screens to support flexible identification, location, and collection of
specific data pieces. The tool emphasizes participants' privacy and agency by
providing full transparency over collected data and allowing easy opt-out. We
designed and built Crepe for research purposes only and in scenarios where
researchers obtain explicit consent from participants. Code for Crepe will be
open-sourced to support future academic research data collection.
