Combo Lock Code Finder by frostryche

Last crawled date: 3 years, 4 months ago

Many of us have combination locks sitting around unused for long periods of time. When we finally need them we realize we can’t remember or find the combination. It’s annoying and frustrating. You can find many ways online to pick these locks but that doesn’t get you the combination if you want to keep using it. This device is for that exact situation. You can put your lock in the device and it will try combinations for you until it gets the correct one and then save/ display the unlock code.
DISCLAIMER: This is for use only on locks that are not attached to anything and that you have have the rights to open. Only the operator of this device is liable for any repercussions of it’s use.
This was inspired by a previous project by Samy Kamkar who made a much more elaborate version. You can find those details on his website here: http://samy.pl/combobreaker/
I tried following his concept with parts that I had around the house and wasn’t able to replicate his success. Instead I made this design that worked much better for me and used components I had already. The major downside is that it is pure brute force. The tricks you find online for measuring pressure of the shackle and doing some math may work on a new lock. Every lock I’ve worked with was stickier, had high friction areas, and was not conducive to these “quick” methods. I recommend watching Samy’s videos to understand how locks work. I was able to narrow down my combinations by picking the locks and looking at the disks inside. I then tested a fraction of the combinations to find the code. Note that there are 64000 possible combinations on a Masterlock combo lock. It will take a few days to test all of those combinations and will likely wear out the lock. In my experience with building this, the locks started to degrade after a few thousand cycles. Narrowing down the possibilities is key to having a functioning lock once you have the combination.
I may continue to revise the design, code, and this post with more detail if I work on this more in the future. For now I have found the codes for all of the locks my friends have sitting around and don’t have any planned work. I’m sure I’m leaving out lots of detail here. Feel free to ask any questions you may have and I can try to fill in any gaps.
Lock Cracker: Automatically try lock combinations until the lock opens. Displays/saves the combination when found.
Written & Designed by Sam Roehler
Revision 3 – 2020/11/28
Refer to images for assembly.
Remember to set the dial to zero before or during the setup loop of the program.
Printed Parts
Assembly Mount pt 1
Assembly Mount pt 2
Backer Plate
Bearing Filler 3to5mm X 2
Spur Gear11
Spur Gear21
Switch Plate
Hardware
Bearing: 5mm ID, 10mm OD, 4mm thick X 2
2.5mm x 14mm Cap Screw X 10
2.5mm x 35mm Cap Screw X 7
2.5mm Nuts X 8 (I used a mix of nylock and regular, use your preference)
2.5mm washers X 13
0.125” ID, 0.75” OD washers X 2 (added frame support for lever arm)
Ziptie, 200mm X 1 (keep the shackle motor on the support)
Super Glue (glue frame together)
Loctite (Optional to hold motor screws in place.
Electronics: You can use whatever you have but the code is setup to work with these parts.
Arduino Mega 2560
SainSmart 1/8" TFT LCD Display (i don't recommend this display but I had one and it worked)
Follow this wiring guide for high speedhttps://www.tweaking4all.com/hardware/arduino/sainsmart-arduino-color-display/
Update pins to use mega SPI instead of uno. Guide herehttps://www.arduino.cc/en/reference/SPI
A4988 Stepper Motor Driver (these are cheap on ebay)
Wiring Guidehttps://www.makerguides.com/a4988-stepper-motor-driver-arduino-tutorial/
Nema 17 Stepper Motor X 2
Bigger the better. A new lock will work with little resistance but will get sticky after hundreds of rotations.
Since I built this without position sensing I needed to guarantee that the dial motor was hitting its position.
I had a geared (1:40) motor on hand which was used for the shackle lifter motor.
I highly recommend having shafts with a face for the screw to set on to prevent it from slipping. Grind in a flat if needed.
capacitor X 2
One for each stepper motor. Most any size will do.
Power Supply, 5V
Used to power the Arduino. Could be a wall supply or a computer if you are watching the serial port
Power Supply, 8-35V X 2
One for each stepper motor. It's technically possible to do this with one supply but life is easier if they are split.
Miscellaneous wires
Bread board