Teardown Tuesday: Keyless Entry Door Lock from buzai232's blog

Smart locks are a popular addition to many modern homes. Some locks can be controlled with Bluetooth connectivity, some with keypads, some with remote controls, and some with all three.
Although this electronic touchpad keyless entry door lock from MiLocks arrived in a plain shipping box, it includes everything needed—except for the installation tools—for adding this lock to your door.electromagnetic lock manufacturers

MiLocks apparently saves money by not adding glamour to their plain shipping boxes, which is perfectly acceptable if you ask me.

The electronics contained inside the external door lock are rather simple; all that's included is a keypad with some LEDs and a cable. The door lock, itself, the metal plate, and the metal enclosures are all impressively sturdy, but one should expect no less given their purpose in life.

Removing the keypad from the door lock was quite simple. Only a few strips of double-sided tape secures the keypad in place.Separating the membrane keypad from the PCB (and its pushbuttons) was a matter of merely unpeeling the keypad from the PCB. The figure below shows the thirteen pushbuttons. The eight LEDs have also been called out.

The pushbuttons, by the way, are not soldered to the PCB but are simply held in place by the membrane keypad, itself.This is the normal design approach when using such snap doom tactile switches, like these (PDF).

The remaining electronics—including the "brains" of this smart door lock—reside inside the in-the-house portion of this door lock assembly. The four AA batteries are easily accessible by sliding the battery cover out of the way. Also located underneath the battery cover are the controls (pushbuttons and switches) for programming the door lock.

With the metal plate removed, we can see the gears, the DC motor, wires, switches, and of course the PCBs. And with all the electronics removed from the door lock enclosure, we can see how simple of a design this electronic touchpad entry system really is.

The smarts of this electronic touchpad keyless entry system consists of only two PCBs, one of which includes the Bluetooth circuitry that uses an apparent OTS (off the shelf) module. The other PCB provides a home for the brains (the microcontroller), the FETs (which are used for dictating the direction of the current flow and, thus, the direction of the motor), and the buzzer.