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Unsafe Lockbox

This instructable was created in fulfillment of the project requirement of the Makecourse at the University of South Florida (
Hello! Do you have not-so-valuable valuables that you want to secure but not so securely?Do you have items that you want to keep secure only by the mere security of appearing secure?Perhaps you simply have an affinity for oddities and a desire to create?Or worse still a course requirement to document your term project?It matters not, keep reading, I will teach you how to construct your very own prostitute safe!The term prostitute safe means, a “secure” containter that opens for anyone with money.
In my application, it is a lockbox, that can unlock with a combination of a 4 digit keypad code and a puzzle using an ultrasonic range-sensor or one American quarter.
The keypad and ultrasonic range-sensor are very secure, it would take a long time to figure out the keypad combination by trial-and-error, but one quarter and the machine unlocks itself, defeating it’s own security.”

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