Combination lock opener
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Combination Lock Opener. Bill Samore Brian Elies Mike Arthur. Intro, Features, Cracking the MasterLock ®, Stepper Motor & Driver- Bill Photo Sensors, Flywheel, Solenoid, H-Bridge- Brian PIC, Keypad, 7-Segment Display, Gate Detection & Opening the Lock- Mike

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Presentation Transcript
Combination lock opener

Combination Lock Opener

Bill Samore

Brian Elies

Mike Arthur


Talk outline

Intro, Features, Cracking the MasterLock®, Stepper Motor & Driver- Bill

Photo Sensors, Flywheel, Solenoid, H-Bridge- Brian

PIC, Keypad, 7-Segment Display, Gate Detection & Opening the Lock- Mike

Time to Open Lock, Ethics- Bill

Testing and Conclusion- Brian

Questions

Talk Outline


Introduction
Introduction

Many people forget the combination to their lock and then need to buy a new one.

If it took a person 15 seconds to enter a combination it would take 11 days 2 hours and 40 minutes to try all 64,000 possible combination.

Our combination lock opening device narrows the possible combinations down to 80, and then tries each one of those to discover the correct combination.


Features
Features

  • Works with MasterLock® combination locks

  • Many lock picking techniques will either destroy the lock or not reveal the combination

  • Our device displays the combination to the lock once it opens the lock

  • A user friendly device that is completely automated


Cracking the masterlock
Cracking the MasterLock ®

  • Find the internal gates

  • To locate the gates pull up on the latch of the lock while rotating the dial- it will get stuck between two numbers or half numbers. Record the midpoint of where the dial sticks.


Cracking the masterlock1

Repeat this process all the way around the lock.

There will be 12 gates.

5 of the gates will be whole numbers and 7 will be half numbers.

The last digit of one of the whole numbers will be different than the rest: This is the 3rd number of the combination!

Cracking the MasterLock ®

Gates from one of our Locks:

3

6.5

9.5

13

16.5

20

23

26.5

29.5

33

36.5

39.5

3rd number of the combo!


Cracking the masterlock2

Take the 3rd number of your combination and divide it by 4.

Take the remainder and record it- this is the first possibility for the first number in the combination. The other possible first numbers of the combination are found by adding 4 to this number until the highest possible number (39) is reached.

Cracking the MasterLock ®

Our example continued:

3rd number of combination = 20

20 % 4 = 0

Possible 1st numbers of the combination:

0,4,8,12,16,20,24,28,32,36


Cracking the masterlock3

Take the remainder from earlier. If it was a 0 or 1 add two to it. If it was a 3 or 4 subtract two from it.

This is the first possibility for the second number in the combination. The other possible second numbers to the combination are found by adding 4 to this number until the highest possible number (39) is reached.

Cracking the MasterLock ®

Our example continued:

Remainder from before = 0

0 + 2 = 2

Possible 2nd numbers of the combination:

2,6,10,14,18,22,26,30,34,38


Cracking the masterlock4

We now have 10X10 = 100 possible combinations. to it. If it was a 3 or 4 subtract two from it.

However all combinations must be either low-high-low or high-low-high this eliminates 20 possible combinations

There are 100-20= 80 possible combinations

Cracking the MasterLock ®

Our example continued:

0-30-20

is low-high-low so it is possible

20-10-20

Is high low high so it is possible

0-10-20

is neither low-high-low nor high-low-high so it is notpossible and we do not need to try it


Stepper Motor to it. If it was a 3 or 4 subtract two from it.

Keypad

Light Sensors

7-SegDisplay

Transformer

Flywheel

Solenoid Motor

PIC

H-Bridge


The stepper motor
The Stepper Motor to it. If it was a 3 or 4 subtract two from it.

  • Detent Torque 200 g-cm (no current is flowing to the motor)

  • Holding Torque 1000 g-cm (current is flowing to the motor)

  • Draws an average of 6 v and 300 mA

  • Power dissipated = IV = 1.8 watt


The stepper motor1
The Stepper Motor to it. If it was a 3 or 4 subtract two from it.

  • Has step angle 1.8º

  • Motor controller has half stepping mode so we can turn the motor in .9º increments

  • There are 40 numbers on the lock and we need to be able to tell the difference between half-numbers therefore we need 360º/(40*2)= 4.5º

  • 4.5º/.9º = 5 half stepper motor steps to turn 1 half number on the lock


Stepper motor driver
Stepper Motor Driver to it. If it was a 3 or 4 subtract two from it.


Testing the motor driver
Testing the Motor & Driver to it. If it was a 3 or 4 subtract two from it.


Photo sensors
Photo Sensors to it. If it was a 3 or 4 subtract two from it.

  • 3 sensor total

  • Each consist of a photo diode and a photo BJT

  • The sensors use the 5 volt supply

  • Dissipate .13 watts of power each


Concept of reflective photo sensing
Concept of Reflective Photo Sensing to it. If it was a 3 or 4 subtract two from it.

White Surface

Black Surface


Photo sensor placement
Photo Sensor Placement to it. If it was a 3 or 4 subtract two from it.

Flywheel (Top)

Whole Number divisions

20 black and 20 white

Half Number divisions

40 black and 40 white


Photo sensor placement cont
Photo Sensor Placement cont. to it. If it was a 3 or 4 subtract two from it.

Flywheel (Bottom)

The black mark is aligned with zero on the lock


Solenoid
Solenoid to it. If it was a 3 or 4 subtract two from it.

Opens the lock

Assists with Gate detection

Connected to the latch of the lock with a zip tie

The lock is held in place via an indentation in the aluminum cross bar


H bridge function
H-Bridge Function to it. If it was a 3 or 4 subtract two from it.

  • H-Bridge acts as interface between solenoid and PIC

  • 2 PIC inputs

  • PIC does not allow both to be High


H bridge for the solenoid
H-Bridge for the Solenoid to it. If it was a 3 or 4 subtract two from it.


H bridge analysis
H-Bridge Analysis to it. If it was a 3 or 4 subtract two from it.

Ip1=Ip4=5ma

Ip2=Ip3=0ma

Is=4.15A

Vs=11.2V

Ps=46.48Watt


H bridge analysis cont
H-Bridge Analysis cont. to it. If it was a 3 or 4 subtract two from it.

Ip1=Ip4=0ma

Ip2=Ip3=26ua

Is=-.7A

Vs=-1.9V

Ps=1.33Watt


Summary of pic
Summary of PIC to it. If it was a 3 or 4 subtract two from it.

  • PIC is main control unit for the device

  • Receives user input from keypad

  • Outputs to 7-segment display

  • Controls Solenoid and Stepper Motor

  • Receives status data from sensors


Keypad
Keypad to it. If it was a 3 or 4 subtract two from it.

  • Keypad is users interface to the device

  • Allows user to input a combination

  • If user hits enter, device begins to unlock lock

  • Input capability also useful in testing


Seven segment display
Seven Segment Display to it. If it was a 3 or 4 subtract two from it.

  • Provides feedback to user from the device

  • Displays the current input by the user

  • Ultimately displays the correct combination of the lock

  • Feedback useful in testing of device


Gate detection
Gate Detection to it. If it was a 3 or 4 subtract two from it.

  • After enter is pressed, unlocker enters gate detection mode

  • Rotates half steps and reads from the sensors as to whether or not the lock is stuck

  • If lock is stuck, rotates to zero to calibrate, displays where locks got stuck, and then returns

  • Three rotations to obtain data


Gate detection state diagram
Gate Detection State Diagram to it. If it was a 3 or 4 subtract two from it.


Last number calculations

PIC is programmed to decide from the three trials what the most likely gates are -based on the results of the trials and known data of where gates often are

From these gates, the PIC identifies the one that is different from the other gates as the last number

Displays last number after calculated

Last number Calculations


Attempts to open lock

Inputting a number and hitting enter twice will enter lock opening mode

Device tries all 80 possible combinations with that last number – displays combination as it is trying it

If this device were to be marketed, these and all other break points would removed

Attempts to open lock


Testing finding most likely gates

Sample gates can be hard coded and the device is able to engage in a mode where it will determine the most likely gates from the hard coded data

Useful to confirm that correct gate locations are being determined

Testing – Finding Most Likely Gates


Acceleration function
Acceleration Function engage in a mode where it will determine the most likely gates from the hard coded data

  • If the clock speed is too fast, motor gets stuck

  • In order to increase the speed that the lock opens an accelerating clock is outputted to the stepper motor

  • Accelerated from 24 ms per step to 6 ms per step


Time to crack lock
Time to crack lock engage in a mode where it will determine the most likely gates from the hard coded data

1.) Find all of the internal gates. This takes about 6 min

2.) Try all 80 of the possible combinations. It takes an average of 17 seconds to try 1 combination or about 23 min to try all 80. Therefore the expected time for step 2 is 11.5 minutes.

Total Expected Time = 6 + 11.5 = 17.5 min


Reliability
Reliability engage in a mode where it will determine the most likely gates from the hard coded data

  • Error rate for gate detection is 25%

  • We use 3 attempts to find each gate reducing the error drastically

  • Device recalibrates (re-zeros) after every attempt to find a gate and after every combination it inputs also improving reliability


Testing

Sensor readings engage in a mode where it will determine the most likely gates from the hard coded data

Combination entry

Gate Detection

Mass Combination entry

Combination Found

Testing


Ethical considerations

Our device should only be used to find the combination to one’s own lock. Not to break into someone else’s!

It would be very difficult to fit a lock into our device if it was attached to anything such as a locker

Ethical Considerations


Conclusion
Conclusion one’s own lock. Not to break into someone else’s!

Strengths

Saves time and money

Can find combination to any Master Lock®

Weakness

Time consuming to change lock

Gate detection unreliable

Future

New software for other brands of locks.

Reduced time to crack lock

Possible Customers

Stores that sell locks

Gym/High School Locker rooms


Credits
Credits one’s own lock. Not to break into someone else’s!

  • Alex Spektor

  • Professor P. Scott Carney

  • People in the parts shop

  • Scott from the machine shop

  • Instructional video from youtube.com

  • Opening Combination Locks by Carl Black


Questions
Questions one’s own lock. Not to break into someone else’s!


State diagram of machine
State Diagram of Machine one’s own lock. Not to break into someone else’s!


Appendix
Appendix one’s own lock. Not to break into someone else’s!


% Error for gate detection one’s own lock. Not to break into someone else’s!


Solenoid resistor values
Solenoid Resistor Values one’s own lock. Not to break into someone else’s!


Light sensor data
Light Sensor Data one’s own lock. Not to break into someone else’s!


Summary of pic ports
Summary of PIC Ports one’s own lock. Not to break into someone else’s!


Schematic of pic
Schematic of PIC one’s own lock. Not to break into someone else’s!


Solenoid specification

Mode: M-82 manufactured: Pontiac Coil Inc. one’s own lock. Not to break into someone else’s!

Exerts a force of about 75 ounces at a distance of .25 inches.

a latching solenoid

Solenoid Specification


Power supply for the solenoid
Power Supply for the Solenoid one’s own lock. Not to break into someone else’s!

  • The solenoid draws approximately 4.15 amps

  • KRII150M 12V 12A power supply supplies power

  • The voltage of the supply was increased to 13.6V.


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