Description

 

The CAL-Solver is a device that would let the user to open any locked 40-digit combination lock without damaging the lock even when it is still attached to the locker door. CAL-Solver is very portable because it is primarily made of aluminum and plastics. Furthermore, it could also be powered with any 12V power source. With a precise high-speed stepper motor and an Arduino Dueminalove microcontroller, the CAL-Solver could open any lock in about 45 minutes. The correct combination code would then be displayed on a LCD display. It is a product conceived in a senior mechanical engineering project class (ME 102B) under the guidance of Professor Liwei Lin at UC Berkeley.

Motivation 

 

The main target market for the Berkeley LockHacker is places where combination locks are heavily used, such as schools, gyms, and storage facilities. In the UC Berkeley gym for example, the lockers are locked with marked UC Berkeley locks such that only the renter and the staff know its combination code. However, those markings often fade away due to extensive handling. CAL-Solver would help the staff to figure out the correct combination of the locks. 

Design Process of CAL-Solver

 

In order to come up with a winning idea, CAL-Solver underwent numerous design iterations and analysis, particularly stress and fatigue analysis. Engineering analysis and calculations were done on every design iterations of CAL-Solver in order to determine which design would work best. Furthermore, sketches and low fidelity prototypes of these inital designs were also built for visualization purposes.

Essential Components of the CAL-Solver

 

The CAL-Solver relies on the following components in order to effectively find a lock combination:

1. Arduino Duemilanove microcontroller as the main controller that gather sensor inputs, process the appropriate algorithm, and give commands to the stepper motor and the solenoid.

2. Mercury Motors 200-steps stepper motor as the primary driver to dial the combinations.

3. Pontiac Coil L-90 Solenoid as the linear actuator to pull the Masterlock open.

4. MiniPower microswitch as the main power switch that would automatically warn the microcontroller once the lock is open.

5. Detachable waterjetted Delrin plastics as a housing for the lock that is going to be hacked.

6. LCD screen to display the correct lock combination