A tape cartridge for a debossing stamper includes a casing, a tape-containing supply spool and a tape take-up spool in the casing, the supply spool having at least one reflector pad visually accessible from the exterior of the casing by an optical reflective sensor for detecting and indicating an amount of tape remaining on the supply spool. In one embodiment the at least one reflector pad is a series of equally spaced reflector pads on an outer periphery of the supply spool. The sensor provides a feedback on each 1/4 revolution of said supply reel, the feedback being received by firmware to track the number of motor steps to drive the take-up spool and to rotate the supply spool a 1/4 turn, and wherein a computer calculates the amount of tape remaining on the supply spool based on supply spool core diameter, take-up spool core diameter and total tape length.