This robot can crack your combination lock in less than 30 seconds

The 3D-printed "Combo Breaker" is brainy enough to figure out your lock's combination and get the thing open in mere seconds.

Ry Crist Senior Editor / Reviews - Labs
Originally hailing from Troy, Ohio, Ry Crist is a writer, a text-based adventure connoisseur, a lover of terrible movies and an enthusiastic yet mediocre cook. A CNET editor since 2013, Ry's beats include smart home tech, lighting, appliances, broadband and home networking.
Expertise Smart home technology and wireless connectivity Credentials
  • 10 years product testing experience with the CNET Home team
Ry Crist
2 min read

Samy Kamkar

Weeks after introducing a manual method that narrows the number of potential combinations to a specific Master Lock down to just eight, intrepid hacker and engineer Samy Kamkar has developed an open source, 3D-printed robot that applies the technique automatically. Calling his gadget the "Combo Breaker," Kamkar claims it can crack a common combination lock in less than 30 seconds.

Kamkar's device uses a technique that feels for telltale points of resistance along a combination lock's dial. With the right algorithm, one can use these resistance points to figure out the first and third digits of a three-digit combination lock, along with eight possibilities for the second digit. From there, it's just a matter of trying each one out. The Arduino-based Combo Breaker is motorized to do exactly that.

On his blog, Kamkar goes into full detail on how the technique works, along with how he designed and constructed the device. Everything is open source, with 3D-printable models ready for download, so there isn't much stopping someone from putting together a Combo Breaker of their own. Of course, there's even less stopping someone from picking up a decent set of bolt cutters.

Kamkar's hacking experience dates back several years, with a long, detailed list of projects that include hacks and bypasses for everything from email clients to wireless doorbells. In 2011, Kamkar analyzed how Google stores and secures location data from Android devices.

Bypassing a cheap combination lock might seem trivial in comparison. Still, it'll definitely have me thinking twice about using one to secure anything more important than a spare set of clothes at the gym.