Building a Safe Cracking Robot

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Contributors: Nate
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Introduction

My wife is amazing; for Christmas this year, she gave me a fire safe she purchased off of Craigslist. It was super cheap because the seller didn’t have the combination. Best present ever.

Step 1) Get a safe that hasn’t been opened.

Step 2) Deploy robot army.

Cracked combination safe

Combination 24/0/66

We were able to crack our Craigslist safe in 40 minutes and 42 seconds! You can re-watch the live cracking, if you’d like. The magic moment occurs at 45:20, but start around 44:30 to get the full scope of what’s happening.

SparkFun Safe Cracker

Brute force robots for combination safes are not new. They are sometimes called an “Autodialer”. And, the robots that use audio feedback are sometimes called “SoftDrill”. The SparkFun Safe Cracker is a variant of the Autodialer. Instead of attempting every combination in the solution domain (called brute forcing), we use some tricks to reduce the domain and shortcuts to speed up the testing process. In addition, the SparkFun Safe Cracker is cheap (~$200), magnetically adheres to the safe, and is non-destructive; when we’re done you’ll never know we were there.