The app doesn't work on my Android device (it's stuck on the "Welcome to Lumenate" screen after signing in). I'm not sure exactly how this app is supposed to function, but assuming it's just similar to something like a stroboscope, it's a bit ridiculous that I have to sign up for an account to use it, when free and open-source alternatives like https://f-droid.org/packages/co.garmax.materialflashlight/ already exist.