How do I protect external roller shutters from crushing when they stop?

You need some form of obstacle detection that cuts power when the shutter stops moving or the motor load rises; the thread says built-in protection in these motors works by monitoring motor power/current, but at 230 V the current change while lowering may be too small to rely on alone [#18243730][#18243840] For a retrofit, people proposed a movement sensor rather than changing the shutter itself: a mechanical pulser/encoder driven by a cord from the shutter, with logic that switches the motor off when pulses stop [#18244951] Another idea was a reed switch in the guide with small neodymium magnets on the slats to generate pulses during movement, again to stop the drive if pulses disappear [#18245615] An IR barrier at the top of the cassette or a microswitch near the cassette was also suggested as a way to detect an abnormal stop, but space in the cassette is limited [#18245182][#18246918] The thread does not converge on a fully proven simple retrofit, so the practical advice is to use a motor with proper obstacle detection if possible or add an external movement/load-detection cut-off [#18246918]