US Patent 10053054 Child car seat for lock-in prevention

A smart seat buckle is disclosed. The smart seat buckle includes a number of connector elements configured to fasten a user to a seat when the smart seat buckle is in a fastened position, a sensor switch coupled to the connector elements and configured to detect the fastened position of the smart seat buckle, and switch on battery power to a battery powered transmitter when the smart seat buckle is in the fastened position, and the battery powered transmitter configured to transmit a signal to prevent locking of a vehicle door from outside of the vehicle, when the battery power of the transmitter is switched on, in response to the sensor switch detecting the fastened position of the smart seat buckle.