Patent ID: 7246450

Claim:
A hand-held electronic device for measuring a size of a conductive fastener, said hand-held electronic device comprising: a portable housing having planar front and side faces, said side face having a linear shape provided with a longitudinal length smaller than a diameter of said front face; top and bottom conductive clamps directly coupled to said side face and spaced from said front face respectively, said bottom clamp being stationary and said top clamp being linearly displaced along said side face such that the fastener is intercalated between said top and bottom clamps during measuring operations, said top and bottom clamps forming a closed electrical circuit when engaged with the fastener; a controller operably coupled to said top clamp in such a manner that said top clamp is linearly displaced downwardly and upwardly when said controller is rotated along first and second directions respectively; and means for measuring a voltage level when said top and bottom clamps contact said fastener, said voltage level being proportionally adjusted based upon the size of said fastener such that said voltage level increases when a linear distance between said top and bottom clamps increases; wherein said voltage level measuring means further comprises a processor; a conversion table electrically coupled to said processor, said conversion table having data stored therein that provides a list of voltage level readings and a corresponding list of fastener sizes associated with said voltage level readings respectively; and a memory electrically coupled directly to said processor and said conversion table, said memory including software instructions that execute a logic algorithm for causing said hand-held electronic device to measure the size of the fastener, wherein said software instructions comprise and execute the steps of a. linearly ramping a first output voltage when a first input voltage is constant; b. applying a reference voltage to an integrator for a fixed time to ramp up an output voltage of said integrator; c. applying an unknown voltage input to said integrator such that said integrator output voltage is caused to ramp back down; d. recording a time period it takes to ramp down said integrator output voltage to zero; and e. calculating said voltage level by multiplying said reference voltage and said fixed ramp-up time divided by said ramp-down time.