We’ve built a $200 open source robot that cracks combination safes using a mixture of measuring techniques and set testing to reduce crack times to under an hour. By using a motor with a high count encoder we can take measurements of the internal bits of a combination safe while it remains closed. These measurements expose one of the digits of the combination needed to open a standard fire safe. Additionally, ‘set testing’ is a new method we created to decrease the time between combination attempts. With some 3D printing, Arduino, and some strong magnets we can crack almost any fire safe.