In various embodiments, a staple cartridge for use in a surgical stapler is disclosed. The staple cartridge comprises a staple body comprising a proximal end and a distal end. A tissue thickness sensing module is positioned adjacent to the distal end of the staple body. The tissue thickness sensing module comprises a controller and a sensor. A power key is located removably adjacent to the staple body. The controller is configured to detect the power key and to maintain the tissue thickness sensing module in a low-power state while the power key is present. When the power key is removed, the controller transitions the tissue thickness sensing module to an active state.
