One or more embodiments describe a magnetic actuator including at least two magnets. One magnet is a semi hard magnet and the other magnet is a hard magnet. The hard magnet is configured to open or close the magnetic actuator. The semi hard magnet and the hard magnet are placed adjacent to each other. A change in magnetization polarization of the semi hard magnet is configured to push or pull the hard magnet) to open or close a digital lock realised with the magnetic actuator. The magnetic actuator can also be used to realise a valve.

Some embodiments include a lock cylinder comprising: a plug assembly having a front portion and a back portion; a housing shell within which the plug assembly is rotatably disposed, wherein the housing shell includes a notch; wherein the back portion of the plug assembly comprises: a locking pin that is movably disposed, and wherein the locking pin is configured to prevent a rotation of the plug assembly when the locking pin is engaged in the notch and prevented from retracting by a multi-stable mechanism; and the multi-stable mechanism having at least two stable configurations corresponding to respectively to a locked state and an unlocked state, wherein the multi-stable mechanism can maintain the stable configurations without consuming energy; wherein, at a first stable configuration, the multi-stable mechanism prevents the locking pin from retracting, and, at a second stable configuration, the multi-stable mechanism enables the locking pin to retract.

Some embodiments include a lock cylinder comprising: a plug assembly having a front portion and a back portion; a housing shell within which the plug assembly is rotatably disposed, wherein the housing shell includes a notch; wherein the back portion of the plug assembly comprises: a locking pin that is movably disposed, and wherein the locking pin is configured to prevent a rotation of the plug assembly when the locking pin is engaged in the notch and prevented from retracting by a multi-stable mechanism; and the multi-stable mechanism having at least two stable configurations corresponding to respectively to a locked state and an unlocked state, wherein the multi-stable mechanism can maintain the stable configurations without consuming energy; wherein, at a first stable configuration, the multi-stable mechanism prevents the locking pin from retracting, and, at a second stable configuration, the multi-stable mechanism enables the locking pin to retract.

An exemplary access control device includes a locking member having a locked position and an unlocked position; an electronic actuator operably connected with the locking member; a switch connected between the electronic actuator and a power supply, the switch having a closed state in which the electronic actuator is connected to the power supply and is operable to maintain the locking member in the unlocked position, the switch having an open state in which the electronic actuator is disconnected from the power supply; and a manual actuator operable to transition the switch between the open state and the closed state.

An exemplary access control device includes a locking member having a locked position and an unlocked position; an electronic actuator operably connected with the locking member; a switch connected between the electronic actuator and a power supply, the switch having a closed state in which the electronic actuator is connected to the power supply and is operable to maintain the locking member in the unlocked position, the switch having an open state in which the electronic actuator is disconnected from the power supply; and a manual actuator operable to transition the switch between the open state and the closed state.