by Mihai Basa
Downloads periodically from URL(s) and saves to time-stamped filenames on external SD card. Keeps you informed of progress through notifications.
Plays a sound and retries in case of errors, and restarts itself if it stops triggering (it rarely does happen). You'll need Periodic Download Delayed Start to allow restarts while avoiding the 30-running-blocks limit.
Right now it downloads every 1 minute from NASA's JWST webcams -- change it to suit your needs. You'll probably want to change the sounds played on errors too, since these are phone-specific.
VERSION 2: added keepawake block that helps with regularity of triggers (but still not perfect).