The Intercept, an online news publication dedicated to what it describes as adversarial journalism, presents Haven, an app created with the insight of Edward Snowden to protect people from evil maid attacks.
The app, which is open-source and currently in Beta, is a collaboration between Snowden (through the Freedom of the Press Foundation) and The Guardian Project. It can be obtained from the Play Store or F-Droid.
Haven, once installed on a smartphone used specifically for this, records sound, movement and video while sending notifications to another smartphone, even directly as Signal notifications, something that can do, if wanted, through the Tor network. The idea being of leaving the device with Haven installed alongside your personal computer, adding another layer of security against someone trying to access it or tempering it without your knowledge.
Read more about Haven here.